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WILSON'S    ANATOMY. 


Digitized  by  the  Internet  Archive 

in  2010  with -funding  from 

Open  Knowledge  Commons 


http://www.archive.org/details/systemofhumananaOOwils 


a^^^^^ 


A    SYSTEM 


HUMAN    ANATOMY, 

GENERAL    AND    SPECIAL. 


BY  EEASMUS  WILSON,  M.D., 

LECTURER  ON  ANATOMY,  LONDON. 


SECOND  AMERICAN  EDITION, 

KDITED  BY 

PAUL    B.    G  O  D  D  A  R  D,    A.  M.,    M.  D., 

LECTURER  ON  ANATOMY  AND  DEMONSTRATOR  IN  THE  UNIVERSITY  OF  PENNSYLVANIA  ; 

MEMBER  OF  THE  AMERICAN  PHILOSOPHICAL  SOCIETY  ;    ACADEMY  OF  NATURAL 

SCIENCES  ;    PHILADELPHIA  MEDICAL  SOCIETY,  ETC.  ETC. 


'"'•BEfv  r  5r,. 

WITH   OVER  TWO  HUNDP.ED  ILLUSTP.ATIONS  BY  GILBERT. 

FROM  THE  SEC0>;D  LONUOJV  EDITION. 


*"y'  PHILADELPHIA: 

LEA    AND   B  L  A  N  C  H  A  R  D. 

* 

1844. 

i 


»'*»  v/  ^       ^      g 


Entered,  according  to  the  Act  of  Congress,  in  the  year  1842,  by 

LEA  AND  BLANCHAK.D, 

in  the  Office  of  the  Clerk  of  the  District  Court  of  llie  United  States  in  and  for 

the  Eastern  District  of  Pennsylvania. 


C.  Shermnn,  Prinler, 

19  St.  James  Street, 


TO 


SIR  ASTLEY  PASTON  COOPER,  Bart.,  F.  R.  S., 


MEMBER  or  THE  INSTITUTE  OF  FRANCE, 


®l)l3  Ulork 


IS  RESPECTFULLY  INSCRIBED, 


IN  ADMIRATION  OF  HIS  GREAT  AND  ACKNOWLEDGED  GENIUS  ; 


AND  OF  HIS  SPLENDID  AND  UNWEARYING  LABOURS 


m  THE  CAUSE  OF  MEDICAL  SCIENCE, 


THE  AUTHOR. 


PREFACE 

TO  THE  FIRST  ENGLISH  EDITION. 


The  favourable  reception  which  my  recent  Work  on  Practical 
and  Surgical  Anatomy  has  received,  both  from  the  Profession 
and  the  Press,  commands  my  first  attention  and  grateful  remem- 
brance on  again  presenting  myself  to  public  notice  as  an  aspirant 
for  honours  in  the  field  of  Medical  Science.  On  the  present 
occasion,  I  submit  the  Anatomist's  Vade  Mecum  to  the  Members 
of  the  Profession,  with  the  fullest  assurance  that  they  will  find  it 
to  be  a  complete  system  of  descriptive  Anatomy,  recording  in  its 
pages,  in  a  clear,  precise,  and  perspicuous  style  of  expression, 
every  important  detail  of  human  structure,  and  the  most  modern 
and  valuable  discoveries  and  researches  in  the  Science  of  Ana- 
tomy. 

To  the  established  practitioner  it  is  a  matter  of  great  impor- 
tance that  he  should  be  possessed  of  the  means,  during  the  few 
spare  hours  which  he  can  abstract  from  his  anxious  and  respon- 
sible duties,  of  easily  and  agreeably  refreshing  his  acquaintance 
wfth  that  science  which  is  the  acknowledged  basis  of  all  safe 
and  skilful  medical  practice.  Of  this  application  of  my  present 
labours  I  have  not  been  unmindful,  in  composing  the  Anatomist's 
Vade  Mecum  ;  and  I  sincerely  trust  that  the  work  will  prove  to 
be  the  instructive  and  interesting  companion  of  his  important 
practical  avocations. 

The  Student  of  Medicine,  from  the  first  moment  of  commen- 
cing his  labours  in  the  study  of  Anatomy,  must  be  made  aware 
of  the  absolute  necessity  that  exists  for  clearness  of  thought,  ex- 
actness of  language,  and  a  rigorous  arrangement  of  ideas.  He 
must  feel  confidence  in  the  knowledge  which  he  possesses,  and 
he  will  then  exhibit  that  confidence  in  the  decision  by  which  all 

B 


PREFACE. 


his  actions  will  be  characterized.  As  a  text-book  for  illustrating 
in  a  precise  method  the  materials  of  instruction,  this  work  is 
especially  designed ;  and  the  severity  and  inflexibility  of  order 
have  not  been  departed  from  in  treating  of  a  single  branch  of  the 
subject." 

Among  the  modern  investigations  of  great  interest  of  which  I 
have  availed  myself,  I  may  particularly  enumerate  those  of  Sir 
Astley  Cooper,  Kiernan,  Henle,  Goodsir,  and  Searle,  in  addition 
to  the  important  observations  of  other  excellent  anatomists. 

My  thanks  are  especially  due  to  Sir  Astley  Cooper,  who,  with 
his  usual  urbanity,  has  furnished  me  with  much  useful  informa- 
tion, and  has  permitted  me  to  emblazon  my  pages  with  the  flatter- 
ing patronage  of  his  name.  I  have  regarded  this  condescension 
of  so  distinguished  a  surgeon  and  physiologist  as  a  sacred  trust 
reposed  in  my  hands,  and  I  have  exerted  myself  to  render  my 
labours  not  unworthy,  of  such  gratifying  confidence. 

I  hope  I  may  be  permitted  to  say  that  the  Engravings  are 
beautiful  examples  of  a  most  instructive  and  valuable  art.  The 
advantages  of  such  illustrations  in  a  demonstrative  science  cannot 
be  too  highly  appreciated.  The  mode  in  which  the  Engravings 
have  been  printed, — a  distinct  branch  of  art  in  itself, — will  not 
pass  unnoticed  by  those  who  are  acquainted  with  the  compli- 
cated process  and  extreme  care  which  are  necessary  to  the 
production  of  the  delicacy  and  force  of  effect  of  such  graphic 
illustrations. 

In  conclusion,  it  gives  me  much  pleasure  to  express  the  obli- 
gations which  are  due  from  me  to  my  friend  and  late  pupil  Mr. 
Oliver  Thomas  Miller,  of  Her  Majesty's  Navy,  for  the  patient 
and  industrious  perseverance  with  which  he  devoted  his  time 
and  ability  during  the  summer  months  to  assist  me  in  the  prose- 
cution of  my  labours. 

55  Upper  Charlotte  Street,  Fitzroy  Square, 
March,  1840. 


PREFACE 

TO  THE  SECOND  ENGLISH  EDITION, 


Two  years  have  not  yet  elapsed  since  the  First  Edition  of  the 
Anatomist's  Vade  Meciim  was  presented  to  the  pubhc  ;  but  that 
short  period,  brief  though  it  is,  has  been  most  eventful  as  regards 
the  history  of  this  work. 

The  most  prominent  of  the  events  to  which  I  allude  is  the  de- 
parture from  this  earthly  sphere  of  the  distinguished  patron  of 
my  undertaking.  When  he  was  pleased  to  crown  my  labours 
with  his  sanction,  and  lend  to  them  the  brightness  of  his  name, 
he  was  in  the  enjoyment  of  perfect  health ;  he  was  still  labouring 
in  the  field  of  Medical  Science,  an  untiring  labourer ;  he  was 
still  looking  forward  to  a  long  vista  of  usefulness  and  benevolent 
action.  Now,  Sir  Astley  Cooper  is  no  more.  It  is  not  my  in- 
tention,— and,  indeed,  if  I  were  so  inclined,  I  should  lack  the 
ability, — to  write  the  eulogium  of  that  universally  esteemed  and 
noble-hearted  man.  I  shall  content  myself  with  remarking,  that 
in  him  I  have  lost  a  kind  and  a  warm  friend,  the  Medical  Pro- 
fession a  distinguished  ornament,  and  society  a  consolation  and  a 
resource  under  the  torments  of  disease.  Sir  Astley  Cooper  was 
doubly  emineiit ;  he  was  great  as  a  scientific  surgeon,  but  he  was 
greater  as  a  man ;  and  though  in  his  former  capacity  his  name 
will  be  remembered  as  long  as  letters  endure,  his  memory  will 
survive  until  the  human  heart  shall  cease  to  vibrate  to  the  note 
of  sympathy  and  benevolence. 

But  while  I  am  thus  humbly  endeavouring  to  do  justice  to  my 
own  feelings  in  recording  a  feeble  tribute  towards  a  great  debt  of 
gratitude  which  I  owe  to  the  memory  of  Sir  Astley  Cooper,  I 
do  not  forget  that  my  warmest  thanks  are  also  due  to  my  other 
patrons,  the  Medical  Practitioners  and  Students  of  Great  Britain, 
and  to  the  conductors  of  the  Medical  Press.     From  the  former  I 


take  this  opportunity  of  acknowledging  the  receipt  of  numerous 
letters  containing  the  most  cheering  and  gratifying  expressions  ; 
and  to  the  latter  I  am  indebted  for  the  independence  of  opinion, 
and  liberality  of  sentiment,  with  which  they  have  regarded  my 
labours. 

It  has  been  no  slight  source  of  gratification  to  me,  that  the 
work  should  have  received  so  much  attention  from  the  profession 
in  distant  countries.  The  Anatomist's  Vade  Mecuni  is  to  be 
reprinted  in  the  United  States  of  America ;  it  is  at  this  moment 
undergoing  translation  at  Berlin  ;  while  repeated  overtures  have 
been  made  to  Mr.  Churchill  for  its  publication  in  France. 

I  have  endeavoured  to  render  the  present  Edition  more  perfect 
than  the  preceding,  by  entering  more  fully  into  the  description 
of  such  parts  as  were  only  scantily  treated  in  the  first.  I  regret 
that  these  additions  have  increased  the  size  of  the  volume, — an 
effect  that  it  has  always  been  my  foremost  desire  to  avoid  ;  for  if 
a  large  and  a  verbose  book  be  at  any  time  a  great  evil,  it  is  so 
to  its  fullest  extent  in  a  volume  which  is  intended  to  record  only 
facts,  as  is  the  case  with  a  work  on  Anatomy. 

In  the  present  Edition,  as  in  the  former,  I  have  availed  myself 
of  the  labours  of  those  who  have  been  pursuing  successfully 
separate  branches  of  our  science.  Of  them,  I  have  recorded  the 
investigations  of  Mr.  Bowman,  of  King's  College,  on  the  minute 
anatomy  of  muscular  fibre;  of  Mr.  Nasmyth,  on  the  developement 
of  the  epithelium ;  and  of  Mr.  Curling,  of  the  London  Hospital, 
on  the  descent  of  the  testis  in  the  foetus.  I  have  also  contributed 
in  this  department  some  original  researches,  which  I  have  myself 
made,  on  the  minute  structure  of  bone. 

The  principal  additions  to  the  present  Edition  will  be  found  in 
the  chapters  on  the  ligaments,  muscles,  nervous  system,  organs 
of  sense,  and  viscera.  I  have  appended  to  each  muscle  a  sepa- 
rate paragraph,  indicating  its  relations  to  surrounding  parts; 
and  have  augmented  the  number  of  wood-cut  illustrations. 

January,  1842. 


PREFACE 


TO  THE  FIRST  AMERICAN  EDITION. 


In  republishing  the  present  work,  it  was  thought  that  its  ori- 
ginal title  "  Wilson's  Anatomist's  Vade  Mecum,"  would  lead  to 
an  incorrect  appreciation  of  the  nature  and  extent  of  the  work ; 
the  term  "  Vade  Mecum"  being  in  this  country  usually  applied 
to  small  and  concise  manuals.  The  present  work  is,  as  its  Anie- 
rican  title  implies,  a  complete  System  of  Human  Anatomy, 
brought  up  to  the  present  day,  and  although  it  is  written  in  a 
curt  and  concise  style,  nothing  is  omitted  which  can  be  deemed 
important  by  the  student  or  the  general  practitioner. 

In  some  points  its  author  had  not  described  parts  and  struc- 
tures with  sufficient  accuracy,  and  had  evidently  neglected  the 
contributions  to  the  science  from  this  side  of  the  water ;  these 
deficiencies  I  have  endeavoured  to  supply  by  notes  and  addi- 
tional illustrations.  Some  few  alterations  of  names  have  been 
made  in  the  Irody  of  the  work,  where  the  author's  names  were 
too  English,  and  not  in  common  use  in  the  United  States. 

The  illustrations  are  by  far  the  most  beautiful  which  have  ever 
appeared  in  any  anatomical  work,  and  much  praise  is  due  Mr. 
R.  S.  Gilbert  of  this  city,  for  the  masterly  and  spirited  manner  in 
which  he  has  copied  them.  The  originals  were  designed  and 
executed  expressly  for  this  work,  by  Bagg,  of  London,  whose 
reputation  in  this  branch  of  art  is  deservedly  high. 

I  have  long  been  convinced  that  the  day  would  come  in  which 
it  would  be  useless  to  present  to  the  public  a  work  on  science, 

c 


Xiv  PEEFACE. 

unless  it  was  accompanied  with  numerous  and  exact  illustrations, 
as  the  road  to  the  mind  is  so  much  shorter  and  easier  through 
the  eye,  than  any  other  avenue.  This  fact  has  been  appreciated 
by  the  student  of  anatomy  for  some  time,  and  although  numerous 
splendid  works  have  appeared,  there  has  been  none  which  gave 
so  many  and  exact  views  at  so  low  a  cost,  as  the  present. 

Paul  B.  Goddakd. 

Philadelphia,  October,  1842. 


PREFACE 
TO  THE  SECOND  AMERICAN  EDITION. 


The  very  rapid  sale  of  the  first  edition  of  this  work,  is  evidence 
of  its  appreciation  by  the  profession,  and  is  most  gratifying  to  the 
author  and  American  editor.  In  preparing  the  present  edition, 
no  pains  have  been  spared  to  render  it  as  complete  a  Manual  of 
Anatomy  for  the  medical  student  as  possible.  A  chapter  on  Histo- 
logy has  therefore  been  prefixed,  and  a  considerable  number  of 
new^  cuts  added.  Among  the  latter  are  included  some  very  fine 
ones  of  the  nerves,  w^hich  were  almost  wholly  omitted  from  the 
original  work.  Great  care  has  also  been  taken  to  have  this 
edition  correct,  and  the  cuts  carefully  and  beautifully  worked, 
and  it  is  confidently  believed  that  it  will  give  satisfaction,  offering 
a  further  inducement  to  its  general  use  as  a  Text  Book  in  the 
various  colleges. 

Philadelphia,  July,  1844. 


CONTENTS 


CHAPTER  T. 


Definition — Ciiemical  composition 
of  bone  —  Division  into 
classes  .... 
Structure  of  bone 
Deveiopement  of  bone 
The  skeleton  .... 
Vertebral  column  ... 

Cervical  vertebrce       .         .         - 

Atlris — Axis 

Vertebra  piominens  ... 

Dorsal  vertebrae  ... 

Lumbar  vertebrse       ... 

General  considerations 

Deveiopement 

Attachment  of  muscles 

Sacrum 

Coccyx     ..... 
Bones  of  the  cranium    .         -        - 

Occipital  bone  ... 

Parietal  bone    .... 

Frontal  bone     .... 

Temporal  bone  .         .         . 

Sphenoid  bone 

Ethmoid  bone  ... 

Bones  of  the  face  .         .         . 

Nasal 

Superior  maxillary 

Lachrymal  bone         .         .         . 

Malar  bone — Palate  bone 

Infurior  turbinated  bone     - 

Inferior  maxillary     ... 
Table  of  developements,  articula- 
tions, &.C.            .          .          . 
Sutures 


OSTEOLOGY. 

Regions  of  the  skull 

-      75 

Base  of  the  skull 

. 

. 

.      79 

37 

Face 

. 

,. 

-      80 

38 

Orbits 

. 

. 

-      81 

41 

Nasal  foss£E 

. 

. 

-      82 

42 

Teeth  . 

. 

. 

.      83 

43 

Structure 

. 

. 

-      85 

44 

Deveiopement  - 

. 

- 

.      86 

44.45 

Growth     - 

. 

. 

-      89 

46 

Eruption  . 

. 

. 

-      90 

46 

Succession 

. 

. 

-      91 

47 

Os  hyoides  - 

. 

. 

-      91 

47 

Thorax  and  upper  extremity 

-      92 

48 

Sternum — Ribs 

. 

. 

.      92 

48 

Costal  cartilages 

. 

. 

.      94 

49 

Clavicle— Scapula 

. 

. 

.  94.95 

50 

Humerus 

. 

. 

-      96 

50 

Ulna 

. 

. 

.      98 

50 

Radius 

. 

. 

-      99 

53 

Carpal  bones     . 

. 

. 

-    100 

54 

Metacarpal  bones 

. 

. 

-    104 

56 

Phalanges 

. 

. 

-     105 

60 

Pelvis  and  lower  extremity 

. 

-    106 

64 

Os  innominatum 

. 

. 

-     106 

65 

Ilium — Ischium 

. 

. 

-     106 

65 

Os  pubis  - 

. 

. 

.    108 

65 

Pelvis  —  Its  Divisions  — 

Axes 

68 

— Diameters 

. 

. 

-     109 

68 

Femur 

. 

. 

.    110 

71 

Patella— Tibia 

. 

. 

-     113 

71 

Fibula 

. 

. 

-    114 

Tarsal  bones     . 

. 

. 

-     115 

73 

Metatarsal  bones 

. 

. 

-    118 

74 

Phalanges 

. 

. 

-     120 

Sesamoid  bones    . 

. 

. 

-     120 

CHAPTER  II. 


THE  LIGAMENTS. 


Forms  of  articulation    -         -         -     122 
Synarthrosis  —  Amphi-arthrosis 

— Diarthrosis  -         -     122.123 
Movements  of  joints      -         -         -     124 

'       c2 


Gliding- — Angular  movement 
Circumduction — Rotation 
General    an.tomy    of    articular 
structures 


124 
124 


124 


CONTENTS. 


Cartilage — Fibro-cartilage          -  124 
Ligament — Synovial  membrane  125 
Ligaments   of   the   truxk  —  Ar- 
rangement        ...  126 
Articulation   of  the   vertebral   co- 

lumn          -         -         -         -  126 
Of  the  atlas  with  the  occipital 

bone           ....  129 
Of  the  axis   with   the   occipital 

bone           -         -         -         -  130 

Of  the  atlas  with  the  axis           -  130 

Of  the  lower  jaw        ...  132 

Of  the  ribs  with  the  vertubrte     -  134 
Of  the  ribs  with  the  sternum, 

and  with  each  other  -         -  135 
Of  the  vertebral  column,  with 

the  pelvis            ...  136 

t)f  the  pelvis      -         -         -         -  136 
Ligaments  of  the  upper   extre- 

MITV            ....  139 

Sterno-clavi  nlar  articulat  on         -  140 

Scapulo-clavicular  articulation       -  141 


Ligaments  of  the  scapula      -        -  142 

Shoulder-joint       -         -         -         -  142 

Elbow-joint  ....  143 

Radioulnar  articulation         .         -  145 

Wrist-joint  .....  146 

Articulations  of  the  carpal  bones  147 

Carpo-metacarpal  articulation        -  148 
Metacarpo-phalangeal    arlicula. 

tion  -         -         -         -  149 

Articulation  of  the  phalanges         -  149 
Ligaments  of  the  lower  extre- 

MITV  ....  150 

Hip-joint 150 

Knee-joint    .....  151 
Articulation   between   the  tibia 

and  fibula  -         -         -  156 

Ankle-joint 157 

Articulation  of  the  tarsal  bones      -  158 
Tarso-metatarsal  articulation         -  160 
Metatarso- phalangeal    articula- 
tion    161 

Articulation  of  the  phalanges         .  161 


CHAPTER  III. 


THE  MUSCLES, 


General  anatomy  of  muscle  - 

Nomenclature — Structure 
Muscles  of  the  head  and  face     - 
Arrangement  into  groups 
Epicranial  region — Dissection 

Occipito-frontalis 
Orbital  group — Dissection     . 
Orbicularis  palpebrarum    - 
Corrugator  supercilii 
Tensor  tarsi      .         .         .         - 

Actions 

Ocular  group — Dissection 

Levator  palpebrae — Rectus  supe- 
rior        .... 
Rectus  inferior  ... 

Rectus  internus         ... 
Rectus   externus — Obliquus    su- 
perior    .         -         .         - 
Obliquus  inferior — Actions 
Nasal  group  .... 

Pyramidaiis  nasi 
Compressor  nasi — Actions 
Superior  labial  group    ... 
Orbicularis   oris — Levator   labii 
superioris  alaeque  nasi     - 
Levator     labii    superioris     pro- 
prius      .         .         .         . 
Levator   anguli  oris  —  Zygoma, 
tici         .         .         .         . 
Depressor  labii   superioris   alte- 
que  nasi 

Actions 

Inferior  labial  group 

Dissection         .         .         .         . 


162 
163 
166 
167 
167 
168 
169 
169 
169 
170 
170 
170 

171 
171 
172 

172 
173 
173 
173 
173 
174 

174 

174 

175 

175 
175 
176 
176 


Inferior  labial  group — continued. 
Depressor  labii  inferioris   . 
Depressor   anguli  oris — Levator 
labii  inferioris    - 

Actions 

Maxillary  group    .         -         -         - 
Masseter — Temporal  muscle     176.177 
Buccinator — External  ptery- 
goid muscle 
Internal  pterygoid  muscle 
Actions     .         .         .         - 
Auricular  group  - 

Dissection  -         -         - 

Attollens   aurem  —  Attrahens 

aurem        -         -         - 
Retrahcns  aurem — Actions    - 
Muscles  of  the  nkck    - 
Arrangement  into  groups 
Superficial  group — Dissection 
Platysma  myoides 
Sterno  -  cleido  .  mastoideus  — 
Actions 
Depressors    of  the    os    iiyoides 
and  larynx 
Dissection  ... 

Sterno-hyoideus  —  Stcrno-thy- 

roidcus       .  .  - 

Thyro-hyoidcus  —  Omo-hyoi- 

dcus 
Actions  ... 

Elevators  of  the  OS  hyoidcs    - 
Dissection 

Digaslricus       ... 
Siylo-hyoideus — mylo-hyoideus 


176 

176 
176 
176 


177.178 

-  178 

-  179 
.  179 
.     179 

-  179 
179 

.  180 

.  180 

-  180 

-  181 

-  181 

-  183 
.     183 

.     183 

183.184 

-  184 

.  184 
.     185 

-  185 

185 


CONTENTS. 


Genio-hyoideus — Genio-hyoglos- 
sus    -         -         -         -  ■      . 
Actions     .... 
Muscles  of  the  tongue  ... 
Hyo-glossus — Lingualis     - 
Stylo-glossus     .         .         -         - 
Palato-glossus — Actions    - 
Muscles  of  the  pharynx 

Dissection  .... 

Constrictor  inferior    ... 

Constrictor  medius — Constrictor 

superior  ... 

Stylo-pliaryng-eus  —  Palato-pha- 

ryngeus — Actions 

Muscles  of  the  soft  pulate 

Dissection  .         -         .         . 

Levator  palati — Tensoi'  palati    . 
Azygos  uviilse — Palato-glossus 
Palato-phiiryngeus — Actions 
Prsevertebral  muscles    ... 
Dissection  .... 

Rectus  anticus  major  —  Rectus 

anticus  minor 
Scalenus  anticus — Scalenus  pos- 
ticus     -         .         .         - 
Longus  colli      .... 
Actions     ..... 
Muscles  of  the  trunk 
Muscles    of   the    back — Arrange, 
ment      .... 
First  layer — Dissection 

Trapezius      .... 
Latissimus  dorsi    ... 
Second  layer — Dissection 
Levator  anguli  scapulte 
Rhomboideus    minor    et    ma- 

.  j"r 

Third  layer — Dissection    - 
Serratus  posticus  superior  et 
inferior       .... 
Splenius  capitis  et  colli 
Fourth  layer — Dissection 

Sacro-lumbalis — Longissimus 
dorsi  .... 

Spinalis  dorsi 
Cervicalis  ascendens — Trans- 

versalis  colli 
Trachelo-mastoideus  —  Com- 
plexus        .... 
Fifth  layer — Dis=iection 
Semispinalis  dorsi  et  colli 
Rectus  posticus,  major  et  mi- 
nor     

Rectus  lateralis — Obliquus  in. 
ferior  .... 

Obliquus  superior 
Sixth  layer — Dissection 

Mnltifidiis  spina2  —  Levatores 

costarum         ... 
Supra -spinales  —  Inter  -  spi- 
nalcs  .... 

Intertransversales 
Actions  .... 

Table  of  origins  and  insertions  of 
the  muscles  of  the  back 


186 

18P 
186 
187 
188 
188 
188 
188 
18i) 

189 

190 
191 
191 
191 
192 
192 
193 
193 

193 


Muscles  of  the  thorax   .         .         .  208 

IntcrcQstales  cxterni  et  interni  208 

Triangularis  sterni    ...  210 

Actions 210 

Muscles  of  the  Abdomen       -         -  210 

Dissection          .         .         -         -  210 

Obliquus  externus  ...  210 
Obliquus  internus — Cremaster  211.212 

Transversalis — Rectus  -  -  213 
Pyramidalis — Quadratus  lura. 

borum — Psoas  parvus        214.215 

Diaphragm        ....  215 

Actions 217 

Muscles  of  the  perineum        .         -  218 

Dissection         ....  218 

Acceleratores  urinae  -  .  219 
Erector   penis  —  Transversus 

perinei        ....  219 

Compressor  urethras  .  .  220 
Sphincter  ani  externus  et  in- 

ternus  ....  221 
Levator  ani — Coccygeus  -  221.222 
Muscles    of  the    female    peri. 

neum         ....  222 


193 

Muscles  of  the  upper  extre- 

194 

mity 

-    223 

195 

Anterior  thoracic  region 

.    224 

195 

Dissection    .... 

-    224 

Pectoralis  major 

-    225 

195 

Pectoralis  minor — Subclavius 

195 

— Actions 

225.226 

196 

Lateral  thoracic  region 

.    226 

196 

Serratus  magnus — Actions 

-    226 

197 

Anterior  scnpular  region 

.    226 

197 

Scapularis          ... 

.    226 

Actions     .... 

.    227 

197 

Posterior  scapular  region 

.    227 

199 

Supra-spinatus  —  Infra-spina- 

tus     .... 

.    227 

199 

Teres  minor — Teres  major 

227.228 

199 

Actions     - 

.    228 

200 

Acromial  region 

.    228 

Deltoid — Actions 

.    228 

200 

Anterior  humeral  region 

-    229 

200 

Dissection 

.     229 

Coraco-biachialis — Biceps 

.    229 

201 

Brachialis  anticus — Actions 

-    230 

Posterior  humeral  region 

-     230 

202 

1  nceps     .... 

.     230 

202 

Anterior  brachial  region 

.    232 

202 

Superficial  layer — Dissection 

.    232 

Pronator  radii  teres 

-    232 

203 

Fle.vor  carpi  radialis 

.    232 

Palmaris  longus    . 

.    232 

203 

Flexor  sublimis  digitorum 

-    233 

203 

Flexor  carpi  ulnaris 

.    234 

203 

Deep  layer — Dissection     . 

.    234 

Flexor  profundus  digitorum 

234 

203 

Flexor  longus  pollicis     - 
Pronator   quadratus  —  Ac 

.    235 

204 

tions 

-    235 

204 

Posterior  brachial  region 

.    235 

204 

Superficial  layer  —  Dissec- 

tion .... 

-    236 

206    ■ 

Supinator  longus  - 

-    236 

XX 


COKTENTS. 


Posterior  brachial  region — continued. 
Extensor    carpi    radialis   lon- 

gior            ....  236 
Extensor    carpi   radialis    bre- 

vior 236 

JExtensor    communis    digito- 

rum.  ....  236 
Extensor  minimi  digiti  -  238 
Extensor  carpi  ulnaris — An- 
coneus ....  238 
Deep  layer — Dissection  .  .  238 
Supinator  brevis  ...  238 
Extensor  ossis  raetacarpi  pol- 

licis  -         -         .         .239 

Extensor  primi  internodii  pol- 

licis  -         -         -         .239 

Extensor    secundi    internodii 

pollicis       -         -         .         .239 

Extensor  indicis    ...  239 

Actions          .         -         -         -  240 

Muscles  of  the  hand      -         -         -  240 

Radial  region — Dissection          -  240 

Ulnar  region — Dissection            .  241 

Palmar  region            ...  242 

Actions 244 

Muscles  of  the  lower  extremity  244 
Gluteal  region — Dissection    .         .246 

Gluteus  maximus      ...  246 

Gluteus  medius  et  minimus        -  247 

Pyriformis         ....  247 
Gemellus   superior  —  Obturator 

internus     ....  248 
Gemellus  inferior  —  Obturator 

externus    ....  248 

Quadratus  femoris    -         -         .  249 

Actions 249 

Anterior  femoral   region — Dissec 

tion 249 

Tensor   vaginae  femoris  —  Sar. 

torius         ....  250 

Rectus— Vastus  externus  .         .  251 

Vastus  internus — Crureus           -  251 

Actions  -        -         -         .252 


Internal  femoral  region — Dissec- 
tion       -         .         -         .252 

Iliacus  internus     ...  252 
Psoas  magnus  —  Pectineus — 

Abductor  longus     -         .  253 
Abductor    brevis  —  Abductor 

magnus — Gracilis  -         •  254 

Actions          ....  254 
Posterior  femoral   region — Dis- 

section             ...  255 

Biceps  flexor  cruris        -         -  255 
Semi-tendinosus — Semi-mem- 

branosus  ...  255 
Actions  ....  256 
Anterior  tibial  region — Dissec- 
tion -  -  -  -  256 
Tibialis  aniicus  ...  257 
Extensor  longus  digitorum  -  257 
Peroneus    tertius  —  Extensor 

proprius  pollicis      -        -  257 

Actions          ....  258 

Posterior  tibial  region        -         -  258 

Superficial  layer — Dissection  258 

Gastrocnemius            -         -  258 

Plantaris  —  Soleus  —  Ac 

tions       .         -        .       259.260 

Deep  layer — Dissection          -  260 

Popliteus  —  Flexor  longus 

pollicis            -         -         -  260 

Flexor  lonjius  digitorum     -  261 

Tibialis  posticus          -         -  261 

Actions      ....  262 

Fibular  region           -  ■      -         -  262 
Peroneus  longus — Peroneus 

brevis     .         -         -       262.263 

Actions      ....  263 

Foot — Dorsal  region          .        -  263 

Plantar  region       -         -         -  264 

First  layer — Dissection      -  264 

Second  layer — Dissection   -  266 

Third  layer — Dissection     -  266 

Fourth  layer      -         -         -  267 

Actions      -         .         -         .  268 


CHAPTER  IV. 


THE  FASCIA. 


General  anatomy           -        -         -  270 

Fahci/f.  of  the  head  and  neck       -  271 

Temporal  fascia         -         -         .271 

Cervical  fascia            ...  271 

Fasciac  of  the  trunk   ...  272 

'I'horacic  fiscia          -         -         -  27<J 

Fascia  transversalia  -         .         -  273 

Oblique  inguinal  hernia         -         -  274 

Congenital  hernia          -         -         -  275 

Encysted  hernia  ....  275 

Direct  inguinal  hernia           .        .  275 


Fascia  iliaca  ....  275 
Fascia  pelvica  ....  276 
Obturator  fascia  .  -  -  .  277 
Superficial  perineal  fascia  -  -  277 
Deep  perineal  fascia  ...  278 
Fascia  of  the  upper  extremity  -  279 
Fascia  or  the  lower  extre- 
mity         ....  280 

Fascia  lata 280 

Femoral  hernia  .         -•       -  282 

Plantar  fascia       .        -         -         .  283 


CONTENTS. 


XXI 


CHAPTER   V. 


THE  ARTERIES. 


General  anatomy  of  arteries  - 

Inosculations — Structure 

Aorta 

Table  of  branches      .         .         . 
Coronary  arteries .         .         .         . 
Arteria  innominata       .         .         . 
Comtnon  carotid  arteries 
External  carotid  artery 

Table  of  branches      .         .         . 

Superior  thyroid  artery 

Ling^ual  artery - 

Facial  artery     .         -         -         - 

Mastoid  artery  .... 

Occipital  artery         ... 

Posterior  auricular  artery  - 

Parotidean  arteries    -         .         . 

Ascending  pharyngeal  artery     - 

Transverse  facial  artery    . 

Temporal  artery 

Internal  maxillary  artery  - 
Internal  carotid  artery ... 

Ophthalmic  artery     ... 

Anterior  cerebral  artery     . 

Middle  cerebral  artery 
Subclavian  artery  .         .         - 

Table  of  branches      ... 

Vertebral  artery         ... 

Basilar  artery    -         .         ... 

Thyroid   axis — Inferior  thyroid 
artery         .... 

Supra-scapular   artery  —  Poste- 
rior scapula        ... 

Circle  of  Willis 


285 

Subclavian  artery — continued. 

286 

Superficialis  cervicis — Profunda 

287 

cervicis      .         -         -         . 

311 

289 

Superior  intercostal  artery — In- 

291 

ternal  mammary 

311 

291 

Axillary  artery     .... 

313 

292 

Table  of  branches 

314 

293 

Brachial  artery     .... 

316 

294 

Radial  artery         .... 

317 

294 

Ulnar  artery          .... 

320 

295 

Thoracic  aorta ;  branches 

322 

296 

Abdominal  aorta;  branches  . 

323 

297 

Phrenic  arteries 

323 

297 

Cceliac  axis — Gastric  artery 

323 

298 

Hepatic  artery .         .         .         - 

324 

298 

Splenic  artery   -         .         -         . 

325 

298 

Superior  mesenteric  artery 

326 

298 

Spermatic  arteries     - 

328 

299 

Inferior  mesenteric  artery 

329 

299 

Renal  arteries  -         -         .         . 

330 

3U2 

Common  iliac  arteries  ... 

331 

304 

Interna]  iliac  artery      ... 

331 

305 

Ischiatic 

333 

306 

Internal  pudic  artery 

334 

306 

External  iliac  artery     - 

337 

307 

Femoral  artery      -         .         .         - 

338 

308 

Popliteal  artery    .... 

342 

308 

Anterior  tibial  artery    ... 

343 

Dorsalis  pedis  artery     ... 

345 

310 

Posterior  tibial  artery   . 

347 

Peroneal  artery 

347 

310 

Plantar  arteries    .... 

348 

310 

Pulmonary  artery 

350 

CHAPTER   VI. 


General  anatomy  - 
Veins  of  the  head  and  neck  . 
Veins  of  the  diploe 
Cerebral  and  cerebellar  veins 
Sinuses  of  the  dura  mater 
Veins  of  the  neck 
Veins  of  the  upper  extremity 
Veins  of  the  lower  extremity 
Veins  of  the  trunk 
Venae  innominatBe     . 


THE  VEINS. 

352 

Veins  of  the  trunk — continued. 

354 

Superior  vena  cava    - 

-     364 

355 

Iliac  veins         -         .         . 

-     365 

355 

Inferior  vena  cava     . 

-     366 

356 

Azyg-os  veins    ... 

.    367 

359 

Vertebral  and  spinal  veins 

-     368 

361 

Cardiac  veins    - 

-    368 

363 

Portal  vein 

-    369 

364 

Pulmonary  veins  - 

.     370 

364 

CONTENTS. 


CHAPTER   VII. 


THE  LYMPHATICS. 


General  anatomy ....  372 

Lymphatics  of  the  head  and  neck  -  373 

Lymphatics  of  the  upper  extremity  374 

Lymphatics  of  the  lower  extremity  375 

Lymphatics  of  the  trunk        •         -  376 


Lymphatics  of  the  viscera      -         -  377 

Lacteals   .....  937 

Thoracic  duct       -         -         -         -  379 

Ductus  lymphaticus  dexter   -         .  381 


CHAPTER   VIII. 


THE  NERVOUS  SYSTEM. 


General  anatomy .  .  .  - 
The  brain  ..... 
Membranes  of  the  encephalon 

Dura  mater       .... 

Arachnoid  membrane 

Pia  mater  .... 

Cerebrum     ..... 

Lateral  ventricle        ... 

Fifth  ventricle  .... 

Third  ventricle .... 

Fourth  ventricle        ... 

Lining  membrane  of  the  ventri- 
cles   

Cerebellum  .  .  -  -  - 
Base  of  the  brain  .... 
Medulla  oblongata  ... 
Diverging  fibres  .... 
Converging  fibres ;  commissures  . 


382 

Spinal  cord  .         .         .         - 

-    407 

387 

Cranial  nerves 

-     411 

387 

Nerves  of  special  sense 

-     412 

387 

Nerves  of  motion 

.    414 

390 

Respiratory  nerves    - 

-    417 

391 

Trifacial  nerve .         -         . 

.    424 

391 

Spinal  nerves        .         .         . 

-    429 

392 

Cervical  plexus 

-    431 

39  (i 

Brachial  plexus 

.    433 

393 

Dorsal  nerves    .         -         - 

-    440 

399 

Lumbar  nerves . 

-    442 

Sacral  nerves     .         .         . 

.     446 

400 

Sympalhefic  system 

-    453 

400 

Cranial  ganglia 

-    454 

401 

Cervical  ganglia 

.     458 

4U3 

Thoracic  ganglia 

.    461 

406 

Lumbar  ganglia 

-    463 

406 

Sacral  ganglia  - 

.    463 

CHAPTER   IX. 


ORGANS  OF  SENSE. 


Nose 

Nasal  fossse  ..... 
Eyeball 

Sclerotic  coat  and  cornea  . 

Choroid  coat;  ciliary  ligament; 
iris 

Retina;  zonula  ciliaris 

Humours .         .         -         .         - 

Physiological  observations 
Appenda!;cs  of  the  eye - 
Lachrymal  apparatus    ... 
Organ  of  hearing. 

External  ear ;  pinna ;  meatus    - 


464 

Organ  of  hearing — continued. 

466 

Tympanum 

.     480 

467 

O.ssicula  auditds 

-     481 

467 

Muscles  of  the  tympanum  . 

.    482 

Internal  car — Vestibule 

.    435 

469 

Semicircular  canals  . 

.     486 

471 

Cochlea    .... 

.     487 

473 

Membranous  Libyrinth 

.    488 

474 

Organ  of  taste — Tongue 

.     491 

475 

Organ  of  touch — Skin 

-    492 

477 

Appendages  to  the  skin — Nails 

-     495 

478 

Hairs — Sebaceous  glands  - 

-     496 

478 

Perspiratory  duels — Pores 

-     496 

CONTENTS. 


CHAPTER  X. 


THE  VISCERA. 

Thorax 

497 

Abdomen — continued. 

Heart  - 

. 

. 

497 

Anus         ... 

. 

532 

Pericardium 

. 

. 

497 

Liver        ... 

. 

539 

Adult  circulation  - 

. 

. 

498 

Kiernan's  researches 

. 

543 

Structure    of    the    heart- 

-Searle's 

Gall  bladder      - 

. 

550 

researches 

. 

. 

504 

Pancreas  ... 

- 

551 

Org-ans  of  respiration 

and 

voice     - 

507 

Spleen       ... 

. 

552 

Larynx — Cartilajres  - 

. 

508 

Supra-renal  capsules- 

- 

553 

Ligaments — Muscles 

. 

509 

Kidneys    ... 

. 

554 

Trachea  and  Bronchi 

. 

513 

Pelvis          ... 

. 

557 

Thyroid  gland  - 

. 

. 

513 

Bladder    - 

. 

557 

Lungs 

. 

. 

514 

Prostate  gland  - 

- 

560 

Pleurae 

. 

. 

517 

Vesiculae  seminales   - 

. 

561 

Mediastinum     - 

. 

. 

517 

Male  organs  of  generation 

562 

Abdomen — Regions 

. 

. 

518 

Penis        ... 

. 

562 

Peritoneum 

. 

. 

518 

Urethra    - 

- 

564 

Alimentary  canal 

. 

523 

Testes       - 

- 

567 

Lips — Cheeks  — 

Gums  —  Pa- 

Female  pelvis 

- 

571 

late    - 

. 

_ 

524 

Bladder — Urethra     - 

. 

572 

Tonsils — Fauces 

. 

. 

525 

Vagina     ... 

. 

572 

Salivary  glands 

, 

. 

525 

Uterus 

. 

573 

Pharynx  - 

. 

. 

527 

Fallopian  tubes 

- 

576 

Stomach  - 

. 

. 

528 

Ovaries     -         .         • 

. 

577 

Small  intestine. 

. 

. 

528 

External  organs  of  generation    . 

577 

Large  intestine  - 

. 

. 

530 

Mammary  glands 

. 

579 

Structure  of  the  intestinal  canal 

532 

CHAPTER  XI, 


ANATOMY  OF  THE  FCETUS. 


Osseous  and  ligamentous  system  . 
Muscular  system  .  .  .  - 
Vascular  system  .... 
Fcetal  circulation  .... 
Nervous  system  ...  - 
Organs  of  sense — Eye — Ear — Nose 
Thyroid  gland  .... 
Thymus  gland  .  -  .  - 
Fcetal  lungs 


581 

Fcetal  heart 

587 

581 

Viscera  of  the  abdomen 

588 

581 

Oniphalo-mesenteric  vessels 

588 

581 

Liver         

588 

584 

Kidneys   and    supra-renal    cap- 

584 

sules     

589 

584 

Viscera  of  the  pelvis      .         .         - 

589 

585 

Testes — Descent        ... 

590 

587 

TABLE  OF  ILLUSTRATIONS. 


1.  Minute  structure  of  bone       -  39 

2.  Id.  id.  id.  -  40 

3.  Cervical  vertebra  ...  44 

4.  Atlas 45 

5.  Axis 45 

6.  Dorsal  vertebra     ...  46 

7.  Lumbar  vertebra  -         -         -  47 

8.  Sacrum         ...         -  49 

9.  Occipital  bone — External  sur- 

face    50 

10.  Occipital  bone — Internal  sur- 

face -----  52 

11.  Parietal  bone — External  sur- 

face -----  53 

12.  Parietal  bone — Internal  sur- 

face 54 

13.  Frontal  bone — External  sur- 

face    55 

14.  Frontal  bone — Internal  sur- 

face    56 

15.  Temporal     bone  —  External 

surface      .         -         .         -  57 

16.  Temporal  bone — Internal  sur- 

face .         -         .         -         -  58 

17.  Sphenoid  bone — Superior  sur- 

face -----  61 

18.  Sphenoid    bone — antero-infe- 

rior  surface         -         .         .  62 

19.  Ethmoid  bone        .         .         -  64 

20.  Superior  maxillary  bone         -  66 

21.  Palate  bone — Internal  surface  69 

22.  Palate   bone  —  External  sur- 

face    70 

23.  Inferior  maxillary  bone  -  72 

24.  Skull — anterior  view     .         .  76 

25.  Base   of  the   skull ;   internal 

view 76 

26.  Base  of  the  skull;   external 

view 79 

27.  Permanent  teeth  -         -         -  83 

28.  Temporary  teeth  .         -         -  84 

29.  Structure  of  tooth  -         -         -  85 

30.  Rudimentary  teeth        -         -  89 

31.  Gubernaculum  dentis    -         -  90 

32.  Os  hyoides   -         -         -         -  91 

33.  Thorax         ...         -  93 

34.  Scapula        ....  95 

35.  Humerus      ....  97 


36.  Ulna  and  Radius  -         .         . 

37.  Bones  of  the  carpus  ;  posterior 

view  ----- 

38.  Hand  ;  anterior  view     - 

39.  Os  innominatum  -         .         - 

40.  I'emur;  anterior  view  - 

41.  Femur;  posterior  view - 

42.  Tibia  and  fibula    - 

43.  Foot;  dorsal  surface 

44.  Foot;  plantar  surface    - 

45.  Ligaments  of  the  vertebrae  and 

ribs;  anterior  view 

46.  Posterior  common  ligament  - 

47.  Ligamenta  subflava 

48.  Ligaments  of  the  atlas,  axis, 

and  occipital  bone;  anterior 
view 

49.  Id. ;  posterior  view 

50.  Id.;  internal  view 

51.  Id.;  internal  view 

52.  Ligaments  of  the  lower  jaw ; 

external  view      ... 

53.  Id. ;  internal  view 

54.  Id. ;  section  -    ,     - 

55.  Ligaments    of   the    vertebral 

column  and  ribs;  posterior 
view  -         .         -         -         - 

56.  Ligaments  of  the  pelvis  and 

hip-joint     -         -         -         - 

57.  Id.  id.         -         -         - 

58.  Ligaments  of  the  sternal  end 

of  the    clavicle    and   costal 
cartilages  .         -         -         - 

59.  Ligaments  of  the  scapula  and 

shoulder-joint     -         .         - 

60.  Ligaments  of  the  elbow ;  in- 

ternal  view         -         -         . 

61.  Id.  external  view 

62.  Coronary  ligament  of  radius  - 

63.  Ligaments  of  the  wrist  and 

hand  .         .         -         - 

64.  Synovial   membranes   of  the 

wrist  -         -         .         . 

65.  Knee-joint;  anterior  view 

66.  Id. ;  posterior  view 

67.  Id.;  internal  view 

68.  Id.;  reflections  of  the  synovial 

membrane 


99 

101 
104 
106 
111 
112 
113 
115 
119 

127 

128 
128 


129 
129 
130 
131 

132 
134 
134 


135 

137 
138 


141 
142 

144 

144 
145 


146 

148 
152 
153 
154 

154 


TABLE  OF  ILLUSTRATIONS. 


69. 

Ankle-joint;  internal  view     - 

157 

109. 

70. 

Id.         external  view     - 

157 

71. 

Id.         posterior  view    - 

159 

110. 

,72. 

Ligaments  of  tlie  sole  of  the 

111. 

foot 

160 

112. 

7.3. 

Minute  structure  of  muscle    - 

163 

74. 

Id.     ,           id.                id. 

104 

75. 

Id.                id.                id. 

165 

113. 

76. 

Id.                id.                id. 

166 

77. 

Muscles  of  the  face 

168 

78. 

Tensor  tarsi  muscle 

170 

114. 

79. 

Muscles  of  the  orbit 

171 

115. 

80. 

Pterygoid  muscles 

178 

81. 

Muscles  of  the  neck ;  super- 

116. 

ficial  and  deep    - 

182 

82. 

Muscles  of  the  tong-ue    - 

187 

117. 

83. 

Muscles  of  the  pharynx 

190 

118. 

84. 

Muscles  of  the  soft  palate 

191 

85. 

Muscles   of  the  prEevertcbral 

119. 

region    .... 

193 

120. 

86. 

Muscles  of  the  back;  1st,  2d, 

and  3d  layer  - 

198 

121. 

87. 

Muscles    of  the    back;    deep 

122. 

layer       .... 

201 

123. 

88. 

Muscular  of  the  anterior  as- 

pect of  the  trunk 

209 

124. 

89. 

Muj^clcs  of  the  lateral  aspect 

of  the  trunk 

214 

125. 

90. 

Diaphragm 

216 

126. 

91. 

Muscles  of  the  perineum 

220 

92. 

Muscles  of  the  anterior  hume. 

127. 

ral  region 

229 

93. 

Triceps  extensor  cubiti 

231 

128. 

94. 

Superficial   layer  of  muscles 

of  the  anterior  aspect  of  the 

129. 

fore-arm     .... 

233 

130. 

95. 

Deep  layer  of  muscles  of  the 

anterior  aspect  of  the  fore- 

131. 

arm            .... 

233 

132. 

96. 

Superficial  layer  of  muscles  ; 

posterior  aspect  of  the  fore- 

133. 

arm             .... 

237 

134. 

97. 

Deep  layer;  posterior  aspect 

13.5. 

of  the  fore-arm  . 

237 

136. 

98. 

Muscles  of  the  hand,  anterior 

aspect        .         .         .         - 

241 

137. 

99. 

Palmar  intcrossei  muscles 

243 

138. 

100. 

Dorsal  interossei  muscles 

243 

139. 

101. 

Muscles  of  the  gluteal  region, 

140. 

deep  layer 

247 

102. 

Muscles  of  the   anterior  and 

141. 

internal  femoral  region 

250 

103. 

Muscles    of  tlie    ghite;il    and 

142. 

posterior  femoral  region 

256 

143. 

104 

Muscles  of  the  anterior  tibial 

region        .... 

259 

U4. 

105 

Muscles  of  the  posterior  tibial 

14.5. 

region,  superficial  layer 

259 

146. 

106 

Muscles  of  the  posterior  tibial 

147. 

region,  fi(;cp  layer 

261 

148. 

107 

Muscles  of  the  sole  of  the  foot, 

14!». 

1st  layer 

265 

150. 

108 

2d  layer    -   i     - 

265 

Muscles  of  the  sole  of  the  foot, 
deep  layer  ... 

Dorsal  interossei  muscles 
Plantar  interossei  muscles 
Section  of  the  neck,  showing 
tlie  distribution  of  the  deep 
cervical  fascia    .         .         - 
Transverse  section  of  the  pel- 
vis, showing  the  distribution 
of  the  fascire 
Deep  perineal  fascia 
Distribution  of  the  deep  peri. 

neal  fascia,  side  view 
Distribution  of  the  fasciae  ;  at 

the  lemoral  arch 
The  great  vessels  of  the  chest 
Branches  of  the  external  caro- 
tid artery  ... 
Internal  maxillary  artery 
Branches    of  the    subclavian 
artery         .... 
The  circle  of  Willis 
Axillary  and  brachial  arteries 
Arteries  of  the  fore-arm — Ra. 
dial  and  ulnar    ... 
Branches    of  the    abdominal 
aorta           .... 
Cosliac  axis  with  its  branches 
The   superior  mesenteric   ar- 
tery 
The   inferior   mesenteric  ar. 
tery            .... 
The  internal  iliac  artery  with 

its  branches 
The  arteries  of  the  perineum 
The   femoral   artery  with  its 
branches    .... 
The  anterior  tibial  artery 
Posterior  tibial  and  peroneal 
artery         .... 
Arteries  of  the  sole  of  the  foot 
Sinuses  of  the  dura  mater 
Sinuses  of  the  base  of  the  skull 
Veins  and  nerves  of  the  bend 

of  the  elbow 
Veins  of  the  trunk  and  neck 
The  portal  vein     ... 
The  thoracic  duct 
The  lateral  ventricles  of  the 
cerebrum   .... 
Longitudinal   section   of  the 

brain      .... 
Base  of  the  brain 
,   Distribution   of  the  fibres   of 
the  brain    .... 
Sections  of  the  spinal  marrow 
,  Olfiictory  nerve,  view  of 
Of)tic  nerves,  view  of     . 
,  Auditory  nerve,  view  of 
,  3d,  4th,  and  6tli  nerves,  view  of 
,  Ncrvesof  the  tongue  and  neck 
,  Faciiil   nerve   and   superficial 
cervical  nerves   . 


266 

268 
268 


272 


276 
277 

278 

281 
288 

295 
300 

308 
311 
315 

319 

324 
326 

327 

329 

332 
333 

338 
346 

346 

349 
357 
358 

362 
365 
370 
380 

393 

397 
404 

405 
410 
412 
413 
"413 
414 
415 

41!) 


TABLE  OF  ILLUSTRATIONS. 


XXVll 


151.  Orig'in  and  distribution  of  the 

eighth  pair  of  nerves 

152.  Branches  of  the  trifacial  nerve 

153.  Axillary  plexus  and  nerves  of 

the  upper  extremity    - 

154.  Nerves  of  front  of  the  fore- 

arm .... 

155.  Nerves  of  back  of  the  fore-arm 

156.  Lumbar    and    sacral    plexus, 

with  the  nerves  of  the  lower 
extremity  .... 

157.  Anterior  crural  nerve    - 

158.  Branches  of  ischiatic  plexus 

159.  Branches  of  popliteal  nerve    - 

160.  Posterior  tibial  nerve     - 

161.  Nerves  of  the  sole  of  the  foot 

162.  Anterior  tibial  nerve 

163.  The   cranial   ganglia   of  the 

sympathetic  nerve 

164.  Great  sympathetic  nerve 

165.  Fibro-cartilages  of  the  nose   . 

166.  Loni^itudinal    section   of  the 

globe  of  the  eye 

167.  A  transverse   section  of  the 

globe  of  the  eye 

168.  Another  transverse  section  of 

the  globe  of  the  eye    . 

169.  A  diagram  of  the  ear     - 

170.  Anatomy  of  the  cochlea 

171.  Osseous  and  membranous  la. 

byrinth  of  the  ear 

172.  The  anatomy  of  the  skin 

173.  Id.  id, 

]  74.  The  heart     .... 

175.  Muscles  of  the  larynx    . 

176.  Id.  id.       - 

177.  Anatomy   of  the   lungs   and 

heart  .... 

178.  The  peritoneum    ... 

179.  The  pharynx 


180. 


423 

425 

181. 

434 

182. 

183. 

437 

184. 

438 

185. 

186. 

187. 

442 

444 

188. 

447 

450 

189. 

450 

190. 

451 

452 

191. 

192. 

454 

459 

193. 

465 

194. 

468 

195. 

471 

196. 

197. 

472 

482 

198. 

487 

199. 

489 

200 

493 

494 

201. 

498 

202. 

510 

203. 

510 

204. 

515 

205. 

519 

527 

Anatomy  of  the  stomach  and 

duodenum  .         -         -     529 

Columns  and  pouches  of  the 

rectum  ....  534 
Peyer's  glands  ...  536 
Muscular  coat  of  the  rectum  538 
The  liver;  its  upper  surface  539 
The  liver;  its  under  surface  541 
Lobules  of  the  liver  .  -  544 
Horizontal    section    of   three 

superficial  lobules       -         -     545 
Horizontal  section  of  two  su- 
perficial lobules  -         .     545 
Section  of  the  kidney    -         -     555 
A  side  view  of  the  viscera  of 

the  male  pelvis  -         -     556 

Neck  of  the  bladder  -  .  559 
A  posterior  view  of  the  blad- 
der and  vesiculae  seminales  561 
Anatomy  of  the  urethra  -  565 
Transverse  section  of  the  tes- 
ticle ....  568 
Human   testis   injected  with 

mercury  -         -         -     569 

Anatomy  of  the  testis  -     570 

A  side  view  of  the  viscera  of 

the  female  pelvis  -  -  573 
Uterus  -         .         .        .     575 

Section  of  the  uterus  (trans. 

verse)  ....  575 
Female  organs  of  generation 

—External  .  .  -  578 
Foetal  circulation  .         .     582 

Section  of  the  thymus  gland       585 
Ducts  of  the  tl:ymus  gland    .     586 
Descent  of  the  testis  in  the 
foetus  .         .         .         .590 

Id.  id.  590 

Vignette. 
Time  and  Death,  Face  title. 


PRELIMINARY  CHAPTER  ON  HISTOLOGY. 

BY  THE  EDITOR. 
A  N  A  T  O  M  y. 

When  we  examine  the  structure  of  an  animal  body  we  find  that 
it  is  composed  of  a  variety  of  textures,  some  of  which  are  univer- 
sally and  others  partially  difiused  through  it.  These  textures,  or 
more  properly  tissues,  when  studied  in  detail,  constitute  what  is 
called  General  Anatomy. 

When  we  take  another  view  of  the  subject,  we  discover  that  the 
body  is  composed  of  a  variety  of  organs — as  the  heart,  brain, 
lungs,  &c.,  which  are  constituted  by  these  tissues,  and  which  are 
possessed  of  a  definite  form,  colour  and  consistency,  the  descrip- 
tion of  which  constitutes  Special  Anatomy. 

In  teaching  Special  Anatomy  we  describe  an  organ  or  viscus  as 
isolated  from  every  other  organ,  or  as  if  it  had  a  separate  existence. 
When  we  begin  to  describe  the  relations  of  neighbouring  organs  to 
each  other  we  approach  Topographical  or  Surgical  Anatomy, 
which  consists  in  a  topographical  division  of  the  body,  or  a  map- 
ping it  out  into  regions,  and  describing  every  tissue  contained  in  a 
region  with  their  relations  to  each  other.  This  to  the  surgeon  is 
by  far  the  most  important  division  of  the  subject,  and. from  its 
subservience  to  this  branch  of  medical  science  it  has  received  the 
name  of  Surgical  Anatomy. 

DIVISION    INTO    TISSUES. 

The  body  of  every  animal  consists  of  various  tissues,  which 
may  be  distinctly  separated  from  each  other  and  recognised  by 
characteristic  properties.  Some  of  these  tissues  present  varieties, 
and  might  even  be  subdivided,  but  as  this  process  would  unnecessa- 
rily complicate  their  study,  it  has  not  been  thought  proper  to 
adopt  it. 

The  solids  alone  can  be  reckoned  as  tissues,  although  the  so-called 
fluids  contain  solid  organized  corpuscles,  and  consequently  may  be 
treated  of  with  the  tissues  proper. 

These  textures  may  therefore  be  enumerated  as  follows: 

1.  Corpuscular  tissue,  found  in  the  blood,  lymph  and  chyle. 

2.  Epidermoid  tissue;  example — epithelium,  cuticle,  hair,  nails. 

3.  Pigmentary  tissue,  found  in  choroid  coat  of  eye,  lung. 

4.  Adipose  tissue,  as  fat. 

5.  Cellular  tissue. 

6.  Fibrous  tissue. 

d2 


XXX  PHYSICAL  PROPERTIES  OF  THE  TISSUES. 

7.  Elastic  tissue,  ligamenta  flava,  middle  coat  of  the  arteries. 

8.  Cartilaginous  tissue,  including  fibro-cartilage. 

9.  Osseous  tissue. 

10.  Muscular  tissue. 

11.  Nervous  tissue. 

12.  Vascular  tissue,  arteries,  veins  and  lynnphatics. 

13.  Serous  tissue,  including  synovial. 

14.  Mucous  tissue. 

15.  Dermoid  tissue. 

16.  Glandular  tissue. 

17.  Refracting  tissue,  lens  of  eye,  cornea. 

18.  Petrous  tissue,  enamel  of  teeth. 

The  whole  of  these  tissues,  how^ever,  may  be  resolved  into — 
1,  simple  fibre;  2,  homogeneous  membrane;  3,  cells  or  granules; 
and  4,  amorphous  matter. 

PHYSICAL    PROPERTIES  OF    THE   TISSUES. 

The  tissues,  like  other  forms  of  matter,  possess  certain  physical 
properties,  such  as  colour,  consistency,  and  density,  which  it  is 
necessary  to  describe  under  their  respective  heads.  One  property, 
however,  is  enjoyed  b)'  every  tissue,  and  this  seems  to  play  a 
most  important  part  in  the  maintenance  of  the  functions  of  life. 
I  allude  to  the  transudation  of  the  solids  by  the  fluids,  which 
is  known  by  the  title  of  endosmosis  and  exosmosis,  names  by 
which  the  process  was  designated  by  Dutrochet,  its  discoverer. 
All  the  tissues  contain  a  certain  quantity  of  water,  and  in  some 
cases  this  amounts  to  four-fifths  of  their  weight,  as  may  be  proved 
by  drying  them ;  and  this  water  is  essential,  not  only  to  their 
vitality,  but  confers  upon  them  their  organic  properties — pliability 
and  elasticity.  As  the  tissues  imbibe  water  in  certain  quantify,  it 
becomes  a  subject  of  study  to  discover  the  manner  by  which  the 
quantity  may  be  increased.  It  is  well  understood  how  pressure 
from  without  would  produce  this  eflfect,  but  even  this  would  be 
aided  by  the  natural  tendency  to  imbibe  and  retain  an  additional 
quantity  of  water  under  favourable  circumstances,  which  is  strongly 
exhibited  by  the  softer  tissues.  Such  a  tissue  saturated  with  water 
placed  in  contact  with  another  tissue  or  a  fluid  having  a  higher 
affinity  for  water,  will  part  with  its  superabundance,  and  if  not 
supplied  from  behind  will  even  part  with  a  portion  of  that  which 
is  essential  to  its  normal  condition.  If,  however,  it  is  supplied 
from  the  other  side,  it  will  continue  to  feed  the  greedy  fluid  on  one 
side  and  freely  drink  from  the  supply  on  the  other.  Thus  a  current 
will  be  established  from  the  water  on  one  side  of  the  tissue  to  the 
fluid  having  a  high  affinity  for  it  on  the  other;  but  this  is  not  all: 
for  tlie  fluid  aHuded  to,  not  content  with  absorbing  all  the  water 
which  the  animal  tissue  supplies  it  with,  in  its  turn  transudes  the 
tissue  to  get  at  and  mix  with  the  water  on  the  other  side,  and  thus 
a  counter-current  is  set  up  in  an  opposite  direction,  which  is  slower, 
however,  than  the  former  one.     These  are  the  currents  which  are 


CHEMICAL  PROritRTIES  OF  THE  TISSUES.  XXXI 

termed  endosmotic  and  exosmotic,  and  which  continue  until  the 
relative  disagreement  of  the  two  liquids  ceases,  and  they  are  equally 
saturated  by  each  other. 

A  curious  circumstance  may  be  mentioned  as  illustrative  of  the 
various  affinities  of  different  substances  for  water.  The  following 
substances,  when  of  the  same  density,  attract  water  from  the  tissues 
in  the  ratio  of  the  numbers  following  them,  viz:  albumen,  12; 
sugar,  11  ;  gum,  5.17  ;  gelatine,  3.  This  peculiar  action  of  liquids 
upon  animal  tissues  is  not  confined  to  liquids,  but  is  also  exerted  upon, 
aeriform  fluids,  and  with  exalted  intensity  and  rapidity.  It  is,  how- 
ever, believed  by  many,  that  the  gases  do  not  pass  as  gases,  but  that 
they  are  absorbed  by  the  water  of  the  tissue  on  one  side,  and  after 
transuding  it  in  solution  are  given  off  on  the  other. 

CHEMICAL    PROPERTIES   OF    THE    TISSUES. 

These  may  be  arranged  under  two  heads. 

1st.  The  properties  of  the  elements  into  which  the  body  of  an 
animal  may  be  resolved  by  decomposition ;  and, 

2d.  The  properties  of  the  definite  organic  compounds  which 
form  the  tissues. 

The  following  chemical  elements  have  been  obtained  from  the 
human  body ;  the  four  first  constituting  the  chief  bulk  of  it,  and 
those  at  the  end  of  the  list  existing  only  in  very  minute  proportion, 
and  perhaps  not  essential  to  it. 

1.  Oxygen. 

2.  Hydrogen. 

3.  Carbon. 

4.  Nitrogen. 

5.  Phosphorus. 
G.  Sulphur. 

7.  Chlorine. 

8.  Fluorine. 

9.  Potassium. 

10.  Sodium. 

11.  Calcium. 

12.  Magnesium. 

13.  Iron. 

14.  Silicon. 

15.  Manganese. 

16.  Aluminum. 

17.  Copper. 

The  definite  organic  compounds  of  which  the  body  is  composed, 
possess  the  following  leading  properties.  1.  They  all  contain  car- 
bon, oxygen  and  hydrogen,  and  the  larger  number  nitrogen.  2. 
They  are  all  decomposed  by  a  red  heat;  and  3d.  They  are  prone 
to  putrefaction  or  spontaneous  decomposition.  They  may  be  thus 
enumerated : 


XXXU  VITAL  PROPERTIES. 

1st.  Azotized  substances,  or  those  which  contain  nitrogen. 

Albumen, 

Fibrin, 

Casein, 

Gelatin, 

Chondrin, 

Alcoholic  extractive. 

Watery  extractive, 

Salivin, 

Ivreatin, 

Pepsin, 

Globulin, 

Mucus, 

Keratin, 

Pigment, 

Hematin, 

Pyin, 

Urea, 

Uric  acid, 

and  some  of  the  biliary  compounds. 

2d.  Non-azotized  substances,  or  those  which  are  destitute  of  ni- 
trogen. 

Fat, 

Sugar  of  milk. 
Lactic  acid, 
and  some  of  the  biliary  compounds. 

VITAL    PROPERTIES. 

The  most  prominent  vital  property  possessed  by  the  tissues  is 
the  power  of  assimilation,  or  of  appropriating  to  themselves  such  of 
the  organizable  substances  presented  to  them  as  may  suit  their  pur- 
poses. This  power  is  supposed  to  be  partly  due  to  chemical  af- 
finity, and  partly  to  vital  affinity.  It  is  most  probable,  however, 
that  future  researches  will  prove  that  the  power  of  assimilating  is 
subject  to  the  ordinary  chemical  laws,  but  under  modifying  cir- 
cumstances, which  can  only  exist  in  a  living  body  or  tissue. 

Another  property  which  is  essentially  vital  is  contractility — a 
phenomenon  which  is  made  manifest  by  the  visible  shrinking  or 
contraction  of  a  living  tissue  when  irritated,  either  by  mechanical 
or  chemical  stimuli.  The  muscular  tissue  exhibits  this  property  in 
the  highest  degree.  This  contractility  must  be  distinguished  from 
the  permanent  contraction  or  crispation  which  a  part  sufiers  when 
exposed  lo  a  high  temperature. 

A  third  vital  property  is  sensibility,  which,  however,  requires  that 
the  tissues  shall  be  united  so  as  to  form  a  continuous  line  from  the 
part  manifesting  it  to  the  brain.  This  property  is  enjoyed  in  very 
diiferenl  degrees  by  the  different  tissues,  and  constitutes  an  impor- 
tant distinction  between  them. 


DEVELOPEMENT  OF  THE  TISSUES. 


DEVELOPEMENT    OF    THE    TISSUES. 

It  cannot  fail  to  excite  surprise  in  the  mind  of  the  tyro,  when  he 
is  told  that  all  the  tissues,  however  diversified,  however  unlike,  ori- 
ginate from  a  similar  form  of  matter,  and  in  the  same  manner. 

This  fact,  which  recent  researches  have  placed  beyond  a  doubt 
as  regards  vegetable  structure,  is  scarcely  cavilled  at  even  with 
regard  to  the  complex  parts  of  an  animal  body.  The  study  of  this 
subject  is,  however,  still  in  progress,  and  it  requires  more  researches 
to  make  us  masters  of  it.  In  the  mean  time  we  will  endeavour  to 
explain  the  mode  of  formation  of  the  tissues  as  far  as  is  known,  and 
for  this  purpose  must  commence  with  the  history  of  the  vegetable, 
as  an  introduction  to  the  more  complicated  but  similarly  formed 
animal. 

All  vegetable  structure  has  its  origin  from  a  minute  vesicle  or 
cell:  an  organized  corpuscle  of  a  rounded  or  oval  shape  in  the 
commencement  of  its  existence,  but  capable  of  assuming  any  shape 
on  coming  in  contact  with  a  fellow  cell,  and  taking  its  place  as  a 
part  of  a  higher  organization. 

This  cell  consists  of  a  thin  transparent  flexible  wall  or  bag  of 
homogeneous  texture,  which  contains  a  fluid  as  well  as  a  more 
solid  body,  which  is  generally  attached  to  one  side  of  the  cell-wall, 
and  is  called  its  nucleus.  As  in  the  progress  of  developement  this 
nucleus  occasionally  disappears,  some  cells  when  examined  are 
found  to  be  destitute  of  it,  and  this  causes  us  to  apply  the  name 
nucleated  cell  to  those  in  which  it  still  exists,  and  simply  cell  to 
those  from  which  it  has  disappeared.  There  is,  however,  no  essen- 
tial difl^erence  between  these  varieties,  except  in  age,  for  it  cannot 
be  questioned  that  every  cell  is  nucleated  in  the  earlier  portions  of 
its  existence. 

The  accompanying  cut  exhibits  a 
group  of  nucleated  vegetable  cells. 

There  is  also  a  little  body  which  is 
sometimes  found  in  the  nucleus,  and 
which  appears  to  differ  in  its  organi- 
zation from  the  rest  of  this  substance, 
and  is  called  nucleolus.     (See  cut.) 

These  cells,  by  aggregation,  form 
every  part  of  the  texture  of  a  vegeta- 
ble, but  whilst  many  of  them  retain  the 

cellular  form,  a  still  greater  number  undergo  such  transformations 
that  their  origin  could  hardly  be  suspected,  had  not  the  series  of 
changes  which  led  to  the  transformation  been  so  faithfully  studied 
and  carefully  verified.  It  may  be  useful  to  detail  some  of  the 
changes  which  the  cells  undergo  in  being  transformed  into  the  more 
complex  structures. 

1.  The  cells  may  simply  enlarge,  retaining  their  form,  or  they 
may  enlarge  at  the  same  time  that  they  alter  their  form. 

1.  Nucleus  attached  to  the  cell-wall.    2.  Nucleoli. 


AMIMAL  CELLS. 


2.  They  alter  their  shape:  thus  if  many  rounded  cells  press  upon 
each  other  a  polyhedral  form  will  be  produced;  or  they  may  elon- 
gate like  a  sausage,  or  they  may  flatten,  or  acquire  a  prismatic  or 
conical  or  tubular  shape. 

3.  Cells  may  coalesce  with  adjoining  cells,  and  thus  form  tubes 
or  ducts,  as  is  seen  in  the  adjoining  cut,  taken 
from  the  cellular  tissue  of  the  common  bulrush, 
where  they  are  of  a  hexagonal  shape. 

4.  Changes  occur  in  the  fluid  contents  of  the 
cell.     Thus    the   contained   fluid   may    be    con- 
verted into  gum,  sugar,  jelly,  colouring  matter, 
essential  oil,  &c.,  or  it  may  solidify  on  the  in- 
ternal face  of  the  cell-wall  and  thus  thicken  it, 
and,  by  a  continuation  of  this  process,  may  deposit    layer  after 
layer  until  the  cavity  of  the  cell  is  nearly  or  quite 
obliterated,  and  it  becomes  a  solid.     These  internal 
layers   are   called  "  secondary   deposits,"    and    are 
well  represented  by  the  accompanying  cut. 

5.  Cells  produce  or  generate  new  cells,  and  this 
may  take  place  in  several  modes. 
We  may  now  apply  these  facts  to  the  developement  of  animal 
tissues,  which,  more  complicated  and  containing   more  elements, 
requires  a  more  complex  process. 

The  animal  commences  from  a  congeries  of  cells,  in  some  of 
which  changes  take  place  precisely  analogous  to  those  of  the  vege- 
table kingdom  ;  in  fact  it  may  be  said,  that  man,  placed  at  the  sum- 
mit of  complex  organization,  originates  from  a  single  cell,  for  in 
what  other  light  can  we  view  that  portion  of  the  ovum  in  which 
the  embryo  is  developed  1 

As  an  instance  of  the  analogy  between  animal  and  vegetable 
origin,  we  may  examine  the  developement  of  cartilage. 

in  the  formation  of  this  tissue  the  cells  first  coalesce,  and  then 
are  thickened  by  a  deposit  on  the  internal  paries  of  the  cell-wall  of 
chondrin,  which  finally  fills  up  the  cell  so  completely,  that  a  scarcely 
perceptible  cavity  is  seen  in  the  centre.  These  changes  are  here 
exhibited. 


We  may  now  examine  the  mode  of  origin  of  the  cell  itself,  before 
proceeding  to  the  study  of  the  more  composite  changes,  which  are 
to  be  found  solely  in  tlie  bodies  of  animals. 

A  cell  originates  in  a  mass  of  soft  or  liquid  matter,  which  is  or- 
ganizable  or  capable  of  being  organized.     In  other  words,  a  liquid 


I.  Cell  vvitli  a  secondary  deposit.     9.  Cell  witli  a  lliird  deposit.     3.  Cell  filled  with 
deposits. 


THANSFOKMATION  OF  ANI3IAL  CELLS. 


formed  of  a  combination  of  elements  fitted  to  produce  an  organized 
structure.  This  substance  is  called  ''blastema"  and  has  the  same 
relation  to  a  cell  as  a  womb  to  an  embryon.  As  an  example,  we 
may  take  the  liquor  sanguinis  or  the  blood,  excluding  its  globules, 
which  in  a  fully  formed  animal  is  a  universally  diffused  blastema. 

The  original  cells  must  be  formed 
in  this  blastema,  but  they  may  in- 
crease in  number,  both  by  new  ones 
forming  in  it,  or  by  the  first  formed 
cells  generating  others  in  their  in- 
terior. 

It  is  probable  that  the  nucleus  is  a 
congeries  of  cell-germs,  and  that 
when  one  is  developed  we  have 
what  we  call  a  nucleated  cell,  but  as 
they  are  all  capable  of  developement, 

they  may  form  a  congeries  of  cells,  which  Vv'ill  consequently  be  desti- 
tute of  nuclei. 


MULTIPLICATION    OF    CELLS. 


Cells  are  multiplied  in  several  diflferent  ways. 

1st.  They  may  be  formed  upon  a  nucleus.  The  mode  in  which 
cells  are  thus  formed,  is  well  shown  by  the  following  cut  from 
Schleiden. 


2d.  The  nucleus  may  be  resolved  into  new  cells  within  the  pri- 
mitive cell,  as  is  shown  by  the  following  cut. 

3d.  Matter  may  collect  around  a  cell,  and  a  new  wall 
be  thus  formed  for  it,  which  may  be  considered  the  cell, 
and  the  primitive  cell  take  the  place  of  its  nucleus.  Such 
cells  are  called  com-plex  cells.  The  best  example  of  this 
is  found  in  the  developement  of  the  ovum  after  impreg- 
nation. 

4th.  A  cell  may  arise  from  the  wall  of  a  previously  formed  cell. 
This  occurs  in  diseased  or  abnormal  deposits. 


TRANSFORMATION    OF   ANIMAL    CELLS. 

1.  Cells  increase  in  size  and  change  their  shape.  The  cut  on 
the  next  page  gives  a  good  idea  of  the  bizarre  and  erratic  forms 
which  cells  occasionally  assume. 


XXXVl 


TRANSFORMATION  OF  THE  BLASTEMA. 


2.  Cells  undergo  an  alteration  of  their  substance  and  contents. 
Thus  the  cell-walls  may  acquire  thickness,  or  the  whole  cell  may 
flatten  and  its  parietes  coalesce,  and  thus  a  simple  flat  disk  be  the 
result.  A  cell  may  also  change  its  chemical  character,  an  instance 
of  which  is  afforded  by  the  cells  of  the  cuticle,  which,  once  soluble 
in  acetic  acid,  become  insoluble  in  the  same  after  acquiring  their 
corneous  character. 


New  deposits  rtiay  also,  as  has  before  been  stated,  occur  within 
the  cell,  so  as  almost  to  obliterate  its  cavity. 

3.  Division  into  fibrils.     This  occurs  in  the  formation  of  feathers 

in  birds.     A  cell  elongates  and  becomes  filled 

'  with  fibres,  which  on  the  sloughing  away  of 

the  cell-wall  remain  and  form  the  structure  of 

the  feathers. 

4.  They  change  their  relations  to  each  other. 
There  is  an  exception  to  this,  however,  in  the 
cells  of  the  blood  or  blood-globules,  which 
always  remain  isolated. 

a.  They  may  be  united  by  an  intervening 
substance,  the  remains  of  the  blastema,  which 
may  thus  form  a  lamina,  as  cuticle. 

h.  They  may  blend  their  parietes,  as  in  the 
case  of  cartilage. 
c.  They  may  coalesce  at  certain  points,  and  their  parietes  dis- 
appearing at  the  place  of  contact,  a  tubular  canal  may  be  formed. 
In  this  way  new  vessels  are  organized.  This  tubular  canal  becom- 
ing the  seat  of  a  new  and  peculiar  deposit,  a  solid  fibre  results,  thus 
muscles  and  nerves  are  formed. 


TRANSFORMATION    OP    THE    BLASTEMA. 

It  is  supposed,  in  addition  to  the  formation  of  tissues  by  cells, 
that  the  blastema  may  organize  itself  into  fibres,  &c.,  but  it  has 
been  observed,  that  when  such  an  occurrence  takes  place,  that 
nuclei  are  always  present.  Homogeneous  films  and  fibres  are  thus 
formed. 

This  can  be  readily  understood  when  we  reflect  that  a  fluid  is  a 
collection  of  homogeneous  particles  which  move  freely  on  each 
other,  and  there  is  no  difficulty  in  supposing  these  particles  to 
approach  each  other  and  coalesce  so  as  to  form  a  film  or  a  fibre. 


SYSTEM   OF   HUMAN  ANATOMY. 


CHAPTER    I. 

OSTEOLOGY. 


The  bones  are  the  organs  of  support  to  the  anuTial  frame ;  they 
give  firmness  and  strength  to  the  entire  fabric,  afford  points  of  con- 
nexion to  the  numerous  muscles,  and  bestow  individual  character 
upon  the  body.  In  the  limbs  they  are  hollow  cylinders,  admirably 
calculated  by  their  conformation  and  structure  to  resist  violence  and 
support  weight.  In  the  trunk  and  head,  they  are  flattened  and  arched, 
to  protect  cavities  and  provide  an  extensive  surface  for  attachment. 
In  some  situations  they  present  projections  of  variable  length,  which 
serve  as  levers  ;  and  in  others  are  grooved  into  smooth  surfaces, 
which  act  as  trochlece  or  pulleys  for  the  passage  of  tendons.  More- 
over, besides  supplying  strength  and  solidity, they  are  equally  adapted, 
by  their  numerous  divisions  and  mutual  apposition,  to  fulfil  every 
movement  which  may  tend  to  the  preservation  of  the  creature,  or 
be  conducive  to  his  welfare. 

According  to  the  latest  analysis  by  Berzelius,  bone  is  composed 
of  about  one-third  of  animal  substance,  which  is  almost  completely 
reducible  to  gelatine  by  boiling,  and  of  earthy  matters  ;  in  the  fol- 
lowing proportions : 

Cartilage         .         .         .  .         .         .     32'17  parts. 

Blood-vessels       .         .  .         .         .            1-13 

Phosphate  of  lime  .....     51-04 

Carbonate  of  lime        .  .         .         .         11*30 

Fluate  of  lime         .         .  .         .         .       2- 

Phosphate  of  magnesia  .         .         .           1*16 

Soda,  chloride  of  sodium  .         .         .1-20 


100-00 


Bones  are  divisible  into  four  classes:  Long,  short, Jiat,  and  irregular. 

The  long  bones  are  found  principally  in  the  limbs,  and  they  con- 
sist of  a  shaft  and  two  extremities.  The  shaft  is  cylindrical  or 
prismoid  in  form,  dense  and  hard  in  texture,  and  hollowed  in  the 
interior  into  a  medullary  canal.  The  extremities  are  broad  and  ex- 
panded, to  articulate  with  adjoining  bones ;  and  cellular  or  cancel- 
lous in  their  internal  structure.     Upon  the  exterior  of  the  bone  are 

4 


33  STRUCTURE  OF  BONE. 

processes  and  rough  surfaces  for  the  attachment  of  muscles,  and 
foramina  for  the  transmission  of  vessels  and  nerves,  and  the  attach- 
ment of  ligaments.  The  character  of  long  bones  is,  therefore,  their 
general  type  of  structure  and  their  divisibility  into  a  central  portion 
and  extremities,  and  not  so  much  their  length  ;  for  there  are  some 
long  bones — as  the  second  phalanges  of  the  toes— which  are  less 
than  a  quarter  of  an  inch  in  length,  and  are  almost  equal,  and  in 
some  instances,  exceed  in  breadth  their  longitudinal  axis.  The  long 
bones  are,  the  clavicle,  humerus,  radius  and  ulna,  femur,  tibia,  and 
fibula,  metacarpal  bones,  metatarsal,  phalanges  and  ribs. 

S/io7't  bones*  are  such  as  have  no  predominance  of  length  or 
breadth,  but  are  irregularly  cuboid  in  form  :  they  are  spongy  in  in- 
ternal texture,  and  invested  by  a  thin  crust  of  condensed  osseous 
tissue.  The  short  bones  are,  the  vertebrce,  coccyx,  carpal  and  tarsal 
bones,  patella,  and  sesamoid  bones. 

F/at  bones  are  composed  of  two  layers  of  dense  bone  with  an  inter- 
mediate cellular  structure,  and  are  divisible  into  surfaces,  borders, 
angles,  and  processes.  They  are  adapted  to  enclose  cavities;  have 
processes  upon  their  surface  for  the  attachment  of  muscles ;  and  are 
perforated  by  foramina,  for  the  passage  of  nutrient  vessels  to  their 
cells,  and  for  the  transmission  of  vessels  and  nerves.  They  articulate 
with  long  bones  by  means  of  smooth  surfaces  plated  with  cartilage, 
and  with  each  other  either  by  cartilaginous  substance,  as  at  the 
symphysis  pubis ;  or  by  suture,  as  in  the  bones  of  the  skull.  The 
two  condensed  layers  of  the  bones  of  the  skull  are  named  tables ; 
and  the  intermediate  cellular  structure  diploe.  The  flat  bones  are 
the  occipital,  parietal,  frontal,  nasal,  lachrymal,  vomer,  sternum, 
scapulae,  and  ossa  innominata. 

Irregular  bones  are  those  which  are  not  distinctly  referrible  to 
either  of  the  above  heads ;  but  present  a  mixed  character,  being 
partly  short  and  partly  flat  in  their  conformation.  The  bones  of  this 
class  are,  the  temporal,  sphenoid,  ethmoid,  superior  maxillary,  in- 
ferior maxillary,  palate,  inferior  turbinated  bones,  os  hyoides,  and 
sacrum. 

Structure. — Tn  structure,  bone  is  composed  of  lamellse,  which  are 
concentric  in  long,  and  parallel  in  flat  bones.  Between  the  lamellse 
are  situated  numerous  small  longitudinal  canals  and  minute  oval 
corpuscules.  The  longitudinal  canals  (canals  of  Havers)  contain  me- 
dullary substance  and  vessels,  and  communicate  with  each  other, 
and  with  the  medullary  canal  or  cells.  Each  longitudinal  canal  is 
surrounded  by  a  series  of  concentric  lamellte,  and  between  these 
lamellse,  as  well  as  between  the  lamellaj  which  constitute  the  great 
medullary  canal  of  the  bone,  the  oval  corpuscules  are  situated.  In 
the  extremities  of  long,  in  short,  and  in  flat  bones,  the  cells  repre- 
sent the  Haversian  canals,  and  are  each  surrounded  by  concentric 
lamelloB ;  indeed,  the  medullary  canal  of  long  bones  may  be  con- 
sidered as  a  single  Haversian  canal  exceedingly  dilated.     The  oval 

*  Wilson's  cliisses  of  short  and  irregular  bones  are  usually  included  in  the  title  ossa 
crassa  or  thick  bones. — G. 


STRUCTURE  OF  BONE.  39 

corpuscules*  are  minute  cells,  from  which  are  given  off  a  number 
of  radiating  and  branching  tubuli,f  which  anastomose  with  the  cor- 
responding tubuli  of  neighbouring  cells.  The  cells  and  tubuli  are 
filled  with  calcareous  substance:  hence  they  have  been  named  cal- 
cigerous  cells  and  tubuli. 

Deutsch,  in  his  excellent  researches^  on  the  minute  structure  of 
bone,  has  described  certain  radiating  lines  which  traverse  the  thick- 
ness of  the  concentric  lamellae.     They  are  thus 
referred  to  by  Miiller  :§    "  It  is  very  remarkable  Fig.  1. II 

that  the  thickness  of  the  lamellae  is  traversed  by 
numerous  lines  which  are  separated  by  very 
small  intervals,  and  which  correspond  in  length 
to  the  thickness  of  the  lamellae,  namely,  ^§-oth  of 
a  line.  Deutsch  supposes  these  lines  to  be  tubes 
in  which  the  calcareous  matter  of  the  bones  is 
deposited C?) ;  if  one  lamella  be  separated  from 
another  the  ends  of  the  lines  are  seen,  he  says, 
of  a  triangular  form.  The  existence  of  these 
fine  tubes(?)  was  hitherto  quite  unknown ;  but  it 
is  not  probable  that  they  serve  for  the  reception 
of  the  calcareous  matter,  for  the  first  appearance 
of  ossification  is  in  the  form  of  a  microscopic 
network  !"^  Having  been  engaged  during  the 
past  summer  (1841),  and  being  still  occupied  with  the  investigation 
of  the  minute  structure  of  bone,  I  have  had  the  good  fortune  to  dis- 
cover the  true  nature  of  the  lines  thus  alluded  to  by  Deutsch  and 
Miiller.  I  have  found  that  the  corpuscules  of  Purkinje  are  arranged 
very  differently  in  different  kinds  of  bones;  that  in  flat  bones,  and  in 
the  thin  lamella  of  cellular  bones,  they  exist  in  great  numbers,  are 
of  considerable  size,  and  are  disposed  with  no  regularity.  Their 
tubuli  are  short,  tapering,  and  tortuous,  and  proceed  irregularly 
from  every  part  of  the  surface  of  the  corpuscules.  In  the  long  bones, 
the  corpuscules  are  apparently  smaller  than  the  preceding,  they  are 
oval  and  flattened,  and  lie  between  the  concentric  lamellae.  Their 
tubuli  are  long  and  only  slightly  undulating,  and  diminish  very  gra- 

*  Discovered  by  Purkinje.  Tliey  are  about  -g\th  of  a  line  througli  their  long- 
diameter. 

t  Discovered  by  Muller.  They  are  very  distinct.  Their  larger  trunks  are  about 
.-_' — th  of  a  line  in  diameter. 

3000  _ 

t  De  penitiori  ossium  stnictura,  observationes.     Dissert,  inaug.  Vratisl. 

§  Physiology,  Translation,  p.  378. 

II  Triinsverse  section  of  the  compact  tissue  of  a  long  bone  :  showing,  1.  The  peri- 
osteal layer.  2.  The  medullary  layer,  and  the  intermediate  Haversian  systems  of 
lamelliB,  each  perforated  by  an  H.  canal. —  Magnified  about  15  diameters. 

^  In  reference  to  this  question,  Dr.  Bayly,  the  translator  of  Muller,  observes, 
"Miescher  does  not  confirm  Deutsch's  statement  as  to  the  still  more  minute  tubes  tra- 
versing the  concentric  lamellae,  although  he  perceived  tlie  radiated  appearance  around 
the  larger  canals,  which  was  produced  by  dots  or  short  lines,  which  do  not  occupy  the 
whole  thicl^ness  of  each  lamel'a.  Some  of  the  linos  appear  to  traverse  more  thin  one 
lamella,  though  the  majority,  as  Miescher  describes,  are  very  short.  They  appear 
more  like  the  separations  between  the  granules  of  cartilage  that  form  the  lamell.T  than 
distinct  tubes."  Dr.  Bayly  has  given  the  figure  of  a  transverse  section  of  an  Haver- 
sian canal,  in  which  Deutsch  and  Miescher's  views  are  clearly  illustrated. 


40 


STRUCTURE  OF  BONE. 


dually  towards  their  termination,  where  they  communicate  with  the 
tubuli  of  other  corpuscules  or  with  the  corpuscules  themselves. 
Among  the  concentric  lamellae  of  the  Haversian  canals,  the  tubuli 

are  given  oft'  irom  the  sur- 
Fig.  2,*  faces,  lying  in  contact  with 

the  lamellaj,  and  they  pro- 
ceed straiiziht  throug;h  the 
lamellee  in  two  directions, 
inwards  towards  the  area  of 
the  Haversian  canal,  or  out- 
wards towards  the  outer- 
most lamellae.  If  in  their 
course  the  tubuli  meet  with 
another  corpuscule,  they  ter- 
minate in  it  or  communicate 
with  its  branches;  but  the 
direct  course  of  the  tubuli 
towards  the  centre  is  never 
interfered  with.  So  evident 
is  the  tendency  of  all  the 
tubuli  to  attain  the  centre, 
that  in  several  corpuscules 
situated  between  the  outer- 
most lamellae,  I  have  observed  the  tubuli  from  the  external  surface 
to  curve  around  the  extremities  of  the  corpuscule,  in  order  to  pro- 
ceed with  those  given  off"  from  the  internal  surface,  to  their  central 
destination.  From  their  general  appearance  in  relation  to  the  la- 
mellae, these  tubuli  seem  to  me  to  deserve  the  title  of  converging 
tubuli ;  they  ail  proceed  towards  the  central  canal,  and  those  which 
reach  that  destination  terminate  upon  its  internal  surface.  The 
trunks  of  the  tubuli  not  unfrequently  give  off"  one  or  two  branches. 
As  regards  their  form,  the  tubuli  are  undoubtedly  cylindrical,  and 
they  probably  contain  calcareous  substance,  as  do  the  calcigerous 
tubuli  described  by  Miiller. 

The  lines  remarl^ed  by  Deutsch  are,  therefore,  according  to  my 

observations,  cylindrical  tubuli,  traversing  the  concentric  lamellce 

of  bone,  communicating  with  the  corpuscules,  and  with  the  cavity 

of  the  Haversian  canal,  and  identical  with  the  calcigerous  tubuli  of 

iiller. 

In  the  fresh  state  bones  are  invested  by  a  dense  fibrous  mem- 
brane, the  periosleum,  covering  every  part  of  their  surface  with  the 
exception   of  the   articular  extremities,   which   are  coated   by  a 

*  Minute  structure  of  bone,  drawn  with  the  microscope  from  nature,  by  Bag-o-. 
Magnified  300  diameters.  1.  One  of  the  Haversian  canals  surrounded  by  its  concentric 
lamellce.  The  corpuscules  are  seen  between  the  lamcllse  ;  but  the  converging-  tubuli 
arc  omitted.  2.  An  Haversian  canal  witii  its  concentric  lameilaB,  Purkinjcan  corpus- 
cules, and  converging  tubuli.  3.  The  area  of  one  of  the  can.ils.  4,  4.  Diiection  of  the 
lamellae  of  the  great  medullary  canal.  IJetwccn  the  lamcIlaD  at  the  upper  part  of  the 
figure,  several  very  long  uor|)uscules  wilh  their  tubuli  are  seen.  In  tlic  lower  part  of 
the  figure,  the  outlines  of  three  other  canals  are  given,  in  order  to  show  their  form  and 
mode  of  arrangement  in  the  entire  bone. 


DEVELOPEMENT   OF  BOKE.  41 

thin  layer  of  cartilage,  Tiie  periosleum  of  the  bones  of  the  skull  is 
termed  'pericranium ;  and  the  analogous  membrane  of  external 
cartilages,  'perichondrium.  Lining  the  interior  of  the  medullary- 
canal  of  long  bones,  the  Haversian  canals,  the  cells  of  the  cancelli, 
and  the  cells  of  short,  flat,  and  irregular  bones,  is  the  medullary 
membrane,  which  acts  as  an  internal  jjeriosteum.  It  is  through  the 
medium  of  the  vessels  supplying  these  membranes  that  the  changes 
required  by  nutrition  occur  in  bones,  and  the  secretion  of  medulla 
into  the  interior  is  effected.  The  medullary  canal  of  long  bones, 
and  the  cells  of  other  bones,  are  filled  v^'ith  a  yellowish  oily  substance 
— the  medulla,  which  is  contained  in  a  loose  cellular  tissue  formed 
by  the  medullary  membrane. 

Developemenl  of  Bone. — The  earliest  trace  of  skeleton  in  the  human 
embryo  is  observed  in  the  presence  of  semi-opaque  lines,  which 
are  seen  through  the  transpai'ent  embryonic  mass.  This  trace  is 
composed  of  a  consistent  granular  jelly,  and  constitutes  ihe  gelatinous 
state  of  osteo-genesis.  In  the  second  or  cartilaginous  state,  the 
semi-opaque  jelly  becomes  dense,  transparent,  and  homogeneous,  the 
change  taking  place  from  the  surface  towards  the  centre,  and  con- 
stituting cartilaginification.  In  the  third  stage,  the  cartilage  is  tra- 
versed by  vessels  carrying  red  blood,  which  proceed  from  the  fibrous 
investment  and  ramify  in  its  interior.  The  cartilage  immediately 
surrounding  these  vessels,  becomes  opaque  and  of  a  yellowish  red 
colour.  In  the  fourth  stage,*  the  earthy  constituents  are  attracted 
from  the  blood  by  the  opaque  cartilage,  which  becomes  altered  in 
character,  and  shoots  into  the  transparent  cartilage  in  the  form  of 
reddish  gray  fibres,  which  communicate  with  each  other  at  acute 
angles  and  constitute  an  areolar  osseous  tissue.  This  is  the  state  of 
ossification.  The  succeeding  changes  are  those  of  condensation  and 
the  formation  of  cells,  the  Haversian  and  medullary  canals. 

Cartilaginification  is  complete  in  the  human  embryo  at  about  the 
sixth  week ;  and  the  first  point  of  ossification  is  observed  in  the 
clavicle  at  about  the  seventh  week.  Ossification  commences  at  the* 
centre,  and  thence  proceeds  towards  the  surface ;  in  flat  bones  the 
osseous  tissue  radiates  between  two  membranes  from  a  central 
point  towards  the  periphery,  in  short  bones  from  a  centre  towards 
the  circumference,  and  in  long  bones  from  a  central  portion,  dia- 
physis,  towards  a  secondary  centre,  epiphf/sis,  situated  at  each 
extremity.  Large  processes,  as  the  trochanters,  are  provided  with 
a  distinct  centre,  which  is  named  a/jophysis. 

The  g7^07vtli  of  the  bone  in  length  takes  place  at  the  extremity  of 
the  diaphysis,  and  in  bulk  by  fresh  deposition  on  the  surface;  while 
the  medullary  canal  is  formed  and  increased  by  absorption  from 
within. 

The  period  of  ossification-\  is  different  in  different  bones;  the  order 
of  succession  may  be  thus  arranged : 

*  The  spot  at  which  this  stage  commences  is  called  the  punctum  ossijicationis. — G. 
+  Burdach,  Physiologie. 

4* 


42 


DEVELOPEMENT  OF  BONE. 


From  the  sixth  to  the  eighth  week,  ossification  commences  first 
in  the  clavicle,  then  in  the  lower  jaw,  upper  jaw,  and  femur. 

From  the  eighth  to  the  tenth  week  in  the  frontal,  occipital, 
humerus,  radius  and  ulna,  tibia  and  fibula,  scapulae,  ribs. 

From  the  tenth  to  the  twelfth  week,  in  the  temporal,  sphenoid, 
malar,  parietal,  palate,  nasal,  vertebrae,  metacarpus,  metatarsus,  last 
phalanges  of  the  hands,  and  feet. 

From  the  third  to  the  fourth  month,  in  the  vomer,  first  and  second 
phalanges,  ossa  innominata. 

From  the  fourth  to  the  fifth  month,  in  the  ethmoid,  lachrymal  and 
spongy  bones. 

From  the  fifth  to  the  sixth  month,  in  the  sternum,  carpus,  and 
tarsus. 

From  the  sixth  to  the  tenth  month  in  the  os  hyoides,  coccyx,  and 
cuboid  bone. 

At  one  year,  in  the  coracoid  process  of  the  scapula,  os  magnum, 
OS  unciforme,  and  internal  cuneiform  bone. 

At  three  years,  in  the  patella,  and  carpal  cuneiform  bone. 

At  four  years,  in  the  external  and  middle  cuneiform  bone. 

At  five  years,  in  the  tarsal  scaphoid  bone,  trapezium,  and  semi- 
lunare. 

At  eight  years,  in  the  carpal  scaphoid. 

At  nine,  in  the  trapezoid,  and  at  the  twelfth  year,  in  the  pisiform 
bone. 

The  ossicula  auditus  are  the  only  bones  completely  ossified  at 
birth. 

The  entire  osseous  framework  of  the  body  constitutes  the  skeleton, 
which  in  the  adult  man  is  composed  of  two  hundred  and  forty-six 
distinct  bones.     They  may  be  thus  arranged : 

Cranium       .......  8 

Ossicula  auditus 6*. 

Face    .         . 14 

Teeth 33 

Vertebral  column 24 

Os  hyoides,  sternum,  and  ribs     ...  26 

Upper  extremities 64 

Pelvis        . 4 

Lower  extremities 60 

Sesamoid  bones 8 


246 


The  skeleton  is  divisible  into  1st.  The  vertebral  column  or  central 
axis.  2.  The  cranium  and  face  or  superior  developement  of  the 
central  axis.  3,  The  hyoid  arch.  4.  The  thoracic  arch  and  upper 
extremities.     5.  The  pelvic  arch  and  lower  extremities. 

*  Wilson  dn.scribcs  three  bones  to  the  ear,  viz :  malleus,  incus  and  stapes,  making'  the 
orhiculare  of  otlior  anatomists  a  part  of  the  stapes.  He  also  counts  thirty-two  teeth 
in  this  enumeration,  which  is  not  common. — G. 


VERTEBRAL  COLUMN.  43 


VERTEBRAL  COLUMN. 

The  Vertthral  column  is  the  first  and  only  rudinnent  of  internal 
skeleton  in  the  lovv'er  Vertebrata,  and  constitutes  the  type  of  that 
great  division  of  the  animal  kingdom.  It  is  also  the  first  developed 
portion  of  the  skeleion  in  man,  and  the  centre  around  which  all  the 
other  parts  are  produced.  In  its  earliest  formation  it  is  a  simple 
cartilaginous  cylinder,  surrounding  and  protecting  the  primitive 
trace  of  the  nervous  system ;  but,  as  it  advances  in  growth  and 
organization,  it  becomes  divided  into  distinct  pieces,  which  consti- 
tute vertehrcB. 

The  vertebrae  are  divided  into  true  and  false.  The  true  vertebrae 
are  twenty-four  in  number,  and  are  classified  according  to  the  three 
regions  of  the  trunk  which  they  occupy,  into  the  cervical,  dorsal,  and 
lumbar.  The  false  vertebrae  consist  of  nine  pieces  united  into  two 
bones, — the  sacrum  and  coccyx.  The  arrangement  of  the  vertebras 
may  be  better  comprehended  by  means  of  the  accompanying  table: 

(      7  Cervical, 
True  vertebrse  24     }    12  Dorsal, 
(      5  Lumbar. 

False  vertebrae  9      \       .  ^      "    ' 
(      4  Coccyx. 

Characters  of  a  Vertebra. — A  vertebra  consists  of  a  body,  two 
laminae,  a  spinous  process,  two  transverse  processes,  and  four  arti- 
cular processes.  The  body  is  the  solid  part  of  the  vertebra ;  and 
by  its  articulation  with  adjoining  vertebrae,  gives  strength  and  sup- 
port to  the  trunk.  It  is  flattened  above  and  below,  convex  in  front, 
and  slightly  concave  behind.  Its  anterior  surface  is  constricted 
around  the  middle,  and  pierced  by  a  number  of  small  openings 
which  give  passage  to  nutritious  vessels. "-^^Upon  its  posterior  surface 
is  a  singular  irregular  opening,  or  several,  for  the  exit  of  the  vencB 
basis  vertebrcp.  or  vertebral  sinuses. 

The  lamincB  commence  upon  the  sides  of  the  posterior  part  of  the 
body  of  the  vertebra  by  two  pedicles;  they  then  expand,  and 
arching  backwards,  enclose  a  foramen  whicli  serves  for  the  protec- 
tion of  the  spinal  cord.  The  upper  and  lower  borders  of  the  laminae 
are  rough  for  the  attachment  of  the  ligamenta  subflava.  The  con- 
cavities above  and  below  the  pedicles  are  the  intervertebral  notches. 
The  spinous  process  stands  backwards  from  the  angle  of  union  of 
the  laminae  of  the  vertebra.  It  is  the  succession  of  these  projecting 
processes  along  the  middle  line  of  the  back,  that  has  given  rise  to 
the  common  designation  of  the  vertebral  column — the  spine.  The 
use  of  the  spinous  process  is  for  the  attachment  of  muscles.  The 
transverse  processes  project  one  at  each  side  from  the  laminre  of  the 
vertebra;  they  are  intended  for  the  attachnnent  of  muscles.  The 
articular  processes,  four  in  number,  stand  upwards  and  downwards 
from  the  laminae  of  the  vertebrae  to  articulate  with  the  vertebra 
above  and  below. 


44  CERVICAL  VERTEBRA. 

Cervical  Vertebrcs. — In  a  cervical  ver- 
'^"  tebra  the  body  is  smaller  than  in  the  other 

regions  ;  it  is  thicker  before  than  behind, 
broad  from  side  to  side,  concave  on  the 
upper  surface  and  convex  below  ;  so  that 
when  articulated,  the  vertebrae  lock  the 
one  into  the  other.  The  lamincB.  are 
broad  and  long,  and  the  inclosed  foramen 
large  and  triangular.  The  superior  and 
inferior  intervertebral  notches  are  nearly- 
equal  in  depth.  The  spinous  process  is 
short  and  bifid  at  the  extremity,  increas- 
ing in  length  from  the  fourth  to  the  seventh.  The  transverse  processes 
are  also  short  and  bifid,  and  grooved  along  the  upper  surface  for  the 
cervical  nerves.  Through  the  base  of  the  transverse  process  is  the 
vertebral  foramenf  for  the  passage  of  the  vertebral  artery  and  vein, 
and  vertebral  plexus  of  nerves.J  The  transverse  processes  in  this 
region  are  formed  by  two  small  developements,  which  proceed,  the 
one  from  the  side  of  the  body,  the  other  from  the  pedicle  of  the 
vertebra,  and  unite  by  their  extremities  so  as  to  enclose  the  circular 
area  of  the  vertebral  foramen.  The  anterior  of  these  developements 
is  the  rudiment  of  a  cervical  rib;  and  the  posterior,  the  true  trans- 
verse process  analogous  to  the  transverse  processes  of  the  vertebrae 
in  the  dorsal  and  lumbar  regions.  The  extremities  of  these  develope- 
ments constitute  the  two  tubercles  of  the  transverse  process. 

The  articular  processes  are  oblique ;  the  superior  looking  upwards 
and  backwards;  and  the  inferior,  downwards  and  forwards. 

There  are  three  peculiar  vertebrae  in  the  cervical  region: — The 
first  or  atlas :  the  second  or  axis  ;§  and  the  seventh  or  vertebra 
prominens. 

The  Atlas  (named  from  supporting  the  head)  is  a  simple  ring  of 
bone  without  body,  and  composed  of  arches  and  processes.  The 
anterior  arch  has  a  tubercle  upon  its  anterior  surface,  for  the  attach- 
ment of  the  longus  colli  muscle ;  and  upon  its  posterior  part  is  a 
smooth  surface,  for  the  articulation  of  the  odontoid  process  of  the  axis. 
The  posterior  arch  is  longer  and  more  slender  than  the  anterior, 
and  flattened  from  above  downwards ;  at  its  middle  is  a  rudimentary 
spinous  process  ;  and  upon  its  upper  surface,  near  the  articular  pro- 
cesses, a  shallow  groove||  at  each  side,  which  represents  a  superior 
intervertebral  notch,  and  supports  the  vertebral  artery,  previously 

*  A  central  cervical  vertebra,  seen  upon  its  upper  surface.  ].  The  body,  concave  in 
the  rniddir;,  and  rising  on  each  side  into  a  sharp  ridfre.  2.  The  laminte.  3.  The  ))edicle 
rendered  concave  by  the  superior  intervertebral  notch.  4.  The  bifid  spinous  process. 
5.  The  bifid  transverse  process.  G.  The  foramen  for  the  vertebral  artery.  7.  The 
superior  articular  process.     8.  The  inferior  articular  process. 

+  There  is  an  objection  to  this  name,  as  it  is  liable  to  bo  confounded  with  the  foramen 
for  the  spinal  medulla. — G. 

X  Snmetimcs,  as  in  a  vertebra  novir  before  me,  a  small  additional  opening  exists  by 
the  side  of  tiic  vertebral  foramen,  in  which  case  it  is  traversed  by  a  second  vein. 

%  Usually  called  verlcbra  deniala. — G. 

II  This  groove  is  sometimes  converted  into  a  foramen. 


ATLAS  AND  AXIS. 


45 


Fig.  4* 


to  its  passage  through  the  dura  mater,  and  the  first  cervical  nerve. 
The  intervertebral  notches  are  peculiar  from  being  situated  behind 
the  articular  processes  instead  of 
before  them,  as  in  the  other  verte- 
bree.  The  transverse  processes  are 
remarkably  large  and  long,  and 
pierced  by  the  foramen  for  the 
vertebral  artery.  The  articular 
processes  are  situated  upon  the 
most  bulky  and  strongest  parts  of 
the  atlas.  The  superior  are  oval 
and  concave,  and  look  inwards, 
so  as  to  form  a  kind  of  cup  for  the  condyles  of  the  occipital  bone, 
and  are  adapted  to  the  nodding  movements  of  the  head ;  the  inferior 
are  circular,  and  nearly  horizontal,  to  permit  of  the  rotary  move- 
ments. Upon  the  inner  face  of  the  lateral  mass  which  supports  the 
articular  processes,  is  a  small  tubercle  at  each  side,  into  which  the 
extremities  of  the  transverse  ligament  are  attached,  a  ligament 
which  divides  the  ring  of  the  atlas  into  two  unequal  segments:  the 
smaller  for  receiving  the  odontoid  process  of  the  axis,  and  the  latter 
to  give  passage  to  the  spinal  cord  and  its  membranes. 

The  Axis  is  named  from  having  a  process  upon  which  the  head 
turns  as  on  a  pivot.  The  body  is  of  a  large  size,  and  supports  a 
strong  process, — the  odontoid, — which  rises  perpendicularly  from 
its  upper  surface.  The  odontoid  process  (processus  dentatus)  pre- 
sents two  articulating  surfaces  ;  one  on  its  anterior  face,  to  articu- 
late with  the  anterior  arch  of  the  atlas ;  the  other  on  its  posterior 
face,  for  the  transverse  ligament.  Upon  each  side  of  its  apex  is  a 
rough  depression,  for  the  attachment  of  the 
alar,  or  moderator  ligaments.  The  lamince 
are  large  and  strong,  and  unite  posteriorly  to 
form  a  long  and  projecting  spinous  process. 
The  transverse  processes  are  quite  rudimen- 
tary, not  bifid,  and  project  only  so  far  as  to 
enclose  the  vertebral  foramen,  which  is  di- 
rected obliquely  outwards  instead  of  perpen- 
dicularly as  in  the  other  vertebrae.  The 
superior  articulating  processes  are  situated 
upon  the  body  of  the  vertebra  on  each  side  of  the  odontoid  process. 


Fig.  5.t 


*  The  upper  surface  of  the  atlas.  1.  The  anterior  tubercle  projecting  frona  the 
anterior  arch.  2.  The  articular  surface  of  the  odontoid  process  upon  the  posterior  sur- 
face of  the  anterior  arch.  3.  Tlie  posterior  arch,  with  its  rudimentary  spinous  pro- 
cess. 4.  The  intervertebral  notch.  5.  The  transverse  process.  6.  The  vertebral  fora- 
men. 7.  Superior  articular  surface,  8.  The  tubercle  for  the  attachment  of  the 
transverse  ligament. 

+  A  lateral  view  of  the  axis.  1.  The  body.  2.  The  odontoid  process.  3.  The 
smooth  facet  on  the  anterior  surface  of  the  odontoid  process  whicli  ariiculales  with  the 
anterior  arch  of  the  atlas.  4.  The  transverse  process  pierced  obliquely  by  the  vertebral 
foramen.  5.  The  spinous  process.  6.  The  inferior  articular  process.  7.  The  superior 
articular  surface. 


46 


DORSAL  VERTEBRA. 


Fig.  6.* 


They  are  circular  and  nearly  horizontal,  having  a  slight  inclination 
outwards.  The  ivferior  articuhiting  processes  look  downwards  and 
forwards,  as  do  the  same  processes  in  the  other  cervical  vertebrae. 
The  lower  surface  of  the  body  is  convex,  and  is  received  into  the 
concavity  upon  the  upper  surface  of  the  third  vertebra. 

The  Vertebra  prominens,  or  seventh  cervical,  approaches  in 
character  to  the  upper  dorsal  vertebra. 
It  has  received  its  designation  from 
having  a  very  long  spinous  process, 
which  is  single  and  terminated  by  a 
tubercle,  and  forms  a  considerable  pro- 
jection on  the  back  part  of  the  neck ; 
to  the  extremity  of  this  process  the 
ligamentum  nuchas  is  attached.  The 
transverse  processes  have  each  a  small 
foramen  for  the  transmission  of  the 
vertebral  vein. 

Dorsal  Vertebrce. — The  body  of  a  dor- 
sal vertebra  is  longer  from  before  back- 
wards than  from  side  to  side,  particularly  in  the  middle  of  the  dorsal 
region  ;  it  is  thicker  behind  than  before,  and  marked  on  each  side 
by  two  half-articulating  surfaces  for  the  heads  of  two  ribs.  The 
■pedicles  are  strong  and  the  lamincB  broad ;  the  foramen  round,  and 
the  inferior  intervertebral  notch  of  large  size.  The  spinous  process 
is  long,  almost  perpendicular  in  direction,  and  terminated  by  a 
tubercle.  The  transverse  processes  are  large  and  strong,  and  directed 
obliquely  backwards.  Upon  their  points  is  a  small  depression  for 
the  articulation  of  the  tubercle  of  a  rib.  The  articular  processes 
are  vertical,  the  superior  facing  directly  backwards,  and  the  inferior 
directly  forv^-ards. 

The  peculiar  vertebrae  in  the  dorsal  region  are  the  first,  ninth, 
tenth,  eleventh,  and  twelfth.  The  first  dorsal  vertebra  approaches 
very  closely  in  character  to  the  last  cervical.  The  body  is  broad 
from  side  to  side,  and  concave  above.  The  superior  articular 
processes  are  oblique,  and  the  spinous  process  horizontal.  It  has 
an  entire  articular  surface  for  the  first  rib,  and  a  half  surface  for 
the  second.  The  ninth  dorsal  vertebra  has  only  one  half  arti- 
cular surface  at  each  side.  The  tenth  has  a  single  entire  articular 
surface  at  each  side.  The  eleventh  and  iioelfih.  have  each  a  single 
entire  articular  surface  at  each  side;  they  approach  in  character  to 
the  lumbar  vertebrae;  their  transverse  processes  are  very  short, 
and  have  no  articulation  with  the  corresponding  ribs.  The  trans- 
verse processes  of  the  twelfth  dorsal  vertebra  are  quite  rudi- 
mentary. 


*  A  lateral  view  of  a  dorsal  vertebra.  1.  The  body.  2,  2.  Articular  facets  for  the 
heads  of  ril)s.  3.  Tlie  surface  for  joining' the  next  vertebra  above.  4.  The  superior 
jntf;rvcrtebral  notch.  5.  The  inferior  intervertebral  notch.  6.  The  spinous  process. 
7.  The  extremity  of  the  transverse  process  marked  by  an  articular  surface  for  the 
tubercle  of  a  rib.  8.  The  two  superior  articular  processes  looking  backwards.  9.  The 
two  inferior  articular  processes  looking  forwards. 


LUMBAR  VEKTEBKiE — GENERAL  CONSIDERATIONS.  47 

Lumbar  Vertebra. — These  are  the  largest  pieces  of  the  vertebral 
column.    The  body  is  broad  and  large, 
and  thicker  before  than  behind.     The  '^' 

pedicles  very  strong ;  the  lamincp,  thick 
and  narrow;  the  inferior  interverte- 
bral notches  very  large,  and  the  fora- 
men large  and  oval.  The  spinous  pro- 
cess is  thick  and  broad.  The  trans- 
verse -processes  slender,  pointed,  and 
directed  only  slightly  backwards.  The 
superior  articular  jjrocesses  are  con- 
cave, and  look  backwards  and  inwards ;  the  inferior,  convex,  and 
look  forwards  and  outwards.  The  last  lumbar  vertebra  differs 
from  the  rest  in  having  the  body  very  much  bevelled  posteriorly, 
so  as  to  be  broad  in  front  and  narrow  behind. 

General  Considerations. — Viewed  as  a  whole,  the  vertebral  column 
represents  two  pyramids  applied  base  to  base,  the  superior  being 
formed  by  all  the  vertebrae  from  the  second  cervical  to  the  last 
lumbar,  and  the  inferior  by  the  sacrum  and  coccyx.  Examined 
more  attentively,  it  will  be  seen  to  be  composed  of  four  irregular 
pyramids,  applied  to  each  other  by  their  smaller  extremities  and  by 
their  bases.  The  smaller  extremity  of  the  uppermost  pyramid  is 
formed  by  the  axis,  or  second  cervical  vertebra :  and  its  base,  by 
the  first  dorsal.  The  second  pyramid  is  inverted  ;  having  its  base 
at  the  first  dorsal,  and  the  smaller  end  at  the  fourth.  The  third 
pyramid  commences  at  the  fourth  dorsal,  and  gradually  enlarges 
to  the  fifth  lumbar.  The  fourth  pyramid  is  formed  by  the  sacrum 
and  coccyx. 

The  bodies  of  the  vertebrae  are  broad  in  the  cervical  region,  nar- 
rowed almost  to  an  angle  in  the  middle  of  the  dorsal,  and  again 
broad  in  the  lumbar  region.  The  arches  are  broad  and  imbricated 
in  the  cervical  and  dorsal  regions,  the  inferior  border  of  each  over- 
lapping the  superior  of  the  next.  In  the  lumbar  region  they  are 
narrow,  and  leave  a  considerable  interval  between  them. 

The  spinous  processes  are  horizontal  in  the  cervical,  and  become 
gradually  oblique  in  the  upper  part  of  the  dorsal  region.  In  the 
middle  of  the  dorsal  region  they  are  nearly  vertical  and  imbricated, 
and  towards  its  lower  part  assume  the  direction  of  the  lumbar 
spines,  which  are  quite  horizontal.  The  transverse  processes  deve- 
loped in  their  most  rudimentary  form  in  the  axis,  gradually  increase 
in  length  to  the  first  dorsal  vertebra.  In  the  dorsal  region  they 
project  obliquely  backwards,  and  diminish  suddenly  in  length  in  the 
eleventh  and  twelfth  vertebras,  where  they  are  very  small.  In  the 
lumbar  region  they  increase  to  the  middle  transverse  process,  and 
again  subside  in  length  to  the  last.  The  intervertebral  foramina 
formed  by  the  juxtaposition  of  the  notches,  are  smallest  in  the  cer- 

*  A  lateral  view  of  a  lumbar  vertebra.  1.  The  body.  2.  The  surface  for  the 
vertebra  above.  3.  The  superior  intervertebral  notch.  4.  The  inferior  intervertebral 
notch.  5.  The  spinous  process.  6.  The  transverse  process.  7.  The  superior  articular 
processes.     8.  The  inferior  articular  processes. 


48  FALSE  VERTEBRAE. 

vical  region,  and  gradually  increase  to  the  last  lumbar.  On  either 
side  of  the  spinous  processes,  and  extending  the  whole  length  of  the 
column,  is  the  vertebral  groove,  which  is  shallow  in  the  cervical, 
and  deeper  in  the  dorsal  and  lumbar  region.  It  lodges  the  principal 
muscles  of  the  back. 

Vievved  from  the  side,  the  vertebral  column  presents  several 
curves,  the  principal  of  which  is  situated  in  the  dorsal  region,  the 
concavity  looking  forwards.  In  the  cervical  and  lumbar  regions 
the  column  is  convex  in  front;  and  in  the  pelvis  an  anterior  con- 
cave curve  is  formed  by  the  sacrum  and  coccyx.  Besides  the 
antero-posterior  curves  a  slight  lateral  curve  exists  in  the  dorsal 
region,  having  its  convexity  towards  the  right  side. 

Devehpement. — The  vertebrae,  with  the  exception  of  the  atlas, 
axis,  and  vertebra  prominens,  are  developed  by  three  points  of 
ossification,  one  for  each  lamella,  and  one  for  the  body.  To  these 
are  afterwards  added  six  additional  centres ;  one  for  each  trans- 
verse process,  two  (sometimes  united  into  one)  for  the  spinous  pro- 
cess, and  one  for  the  upper  and  under  surface  of  the  body.  The 
atlas  has  five  centres;  one  (sometimes  two)  for  the  anterior  arch, 
one  for  each  lateral  mass,  and  two  for  the  posterior  arch.  The 
axis  has  five  original  centres;  one  (sometimes  two)  for  the  body, 
two  for  the  odontoid  process,  and  one  for  each  lamella.  The  vertebra 
prominens  has  likewise  five ;  one  for  the  body,  one  for  each  anterior 
segment  of  the  transverse  process,  and  one  for  each  lamella. 

The  ossification  of  the  arches  of  the  vertebrae  commences  from 
above,  and  proceeds  gradually  downwards;  hence  arrest  of  de- 
velopement  gives  rise  to  spina  bifida,  generally  in  the  loins.  Ossi- 
fication of  the  bodies,  on  the  contrary,  commences  from  the  centre, 
and  proceeds  from  that  point  towards  the  extremities  of  the  column  ; 
hence  imperfection  of  the  bodies  occurs  either  in  the  upper  or  lower 
vertebrae. 

Attachment  of  muscles. — To  the  Atlas  are  attached  ten  pairs  of 
muscles:  the  longus  colli,  rectus  anticus  minor,  rectus  lateralis, 
rectus  posticus  minor,  obliquus  superior  and  inferior,  splenius  colh, 
levator  anguli  scapulae,  first  interspinous,  and  first  intertransverse. 

To  the  axis  are  attached  eleven  pairs,  viz :  the  longus  colli,  inter- 
transversales,  obliquus  inferior,  rectus  posticus  major,  interspinales, 
semi-spinalis  colli,  multifidus  spinae,  levator  anguli  scapulae,  splenius 
colli,  transversalis  colli,  and  scalenus  posticus. 

To  the  remaining  vertehrce  generally,  thirty-two  pairs;  viz.  fos- 
teriorly,  the  trapezius,  latissimus  dorsi,  levator  anguli  scapulae,  rhom- 
boideus  minor  and  major,  serratus  posticus  superior  and  inferior, 
splenius,  sacro-lumbalis,  longissimus  dorsi,  spinalis  dorsi,  cervicalis 
ascendens,  transversalis  colli,  trachelo-mastoideus,  complexus,  semi- 
spinalis  dorsi  and  colli,  multifidus  spinae,  interspinales,  supraspinales, 
interlransversales,  levatores  costarum, — anteriorly,  the  rectus  anticus 
major,  longus  colli,  scalenus  anticus  and  posticus,  psoas  magnus, 
psoas  parvus,  quadratus  lumborum,  diaphragm,  obliquus  internus 
and  transversalis. 


SACRUM  AND  COCCYX.  49 

The  Sacrum  is  a  triangular  bone,  situated  at  the  lower  extremity 
of  the  vertebral  column,  and  formed  by  the  consolidation  of  five 
false  vertebrae.  It  is  divisible  into  an  anterior  and  posterior  surface, 
two  lateral  and  a  superior  border,  and  an  inferior  extremity. 

The  anterior  surface  is  concave,  and  marked  by  four  transverse 
lines,  which  indicate  its  original  constitution  of  five  separate  pieces. 
At  the  extremities  of  these  lines,  on  each  side,  are  the  four  anterior 
sacral  foramina,  which  diminish  in  size  from  above  downwards,  and 
transmit  the  anterior  sacral  nerves.  The  projection  of  the  superior 
piece  is  called  the  promontory  of  the  sacrum. 

The  posterior  surface  is  convex.  Upon  the  middle  line  is  a  rough 
crest  formed  by  the  rudiments  of  four  spinous  processes,  the  fifth 
remaining  undeveloped,  and  exposing  the  lower  termination  of  the 
sacral  canal.  The  rudiments  of  the  fifth  are  situated  one  on  each  side 
of  the  termination  of  the  sacral  canal ;  they  are  named  the  sacral 
cornua,  and  articulate  with  the  cornua  of  the  coccyx.  Parallel  with 
the  middle  line,  on  each  side,  are  the  openings  of  the  four  posterior 
sacral  foramina  ;  they  are  smaller  than  the  anterior,  and  transmit  the 
posterior  sacral  nerves.  Immediately  external  to  each  of  the  pos- 
terior sacral  foramina  is  a  tubercle,  representing  a  rudimentary 
transverse  process.  The  first  transverse  tubercle  corresponds  with 
the  angle  of  the  superior  border  of  the  bone ;  the  second  is  small, 
and  enters  into  the  formation  of  the  sacro-iliac  articulation  ;  the 
third  is  large,  and  gives  attachment  to 
the    oblique    sacro-iliac    ligament;    the  *'?•  o- 

fourth  a.nd  fifth  are  smaller  and  serve  for 
the  attachment  of  the  sacro-ischiatic 
ligaments.  The  lateral  border  presents  ^ 
superiorly  a  broad  and  ear-shaped  sur- 
face to  articulate  with  the  ilium ;  and 
inferiorly  a  sharp  edge,  to  which  the 
greater  and  lesser  sacro-ischiatic  liga- 
ments are  attached.  On  the  superior 
border,  in  the  middle  line,  is  an  oval 
articular  surface,  which  corresponds 
with  the  under  part  of  the  body  of  the 
last  lumbar  vertebra ;  and  on  each  side,  a 
broad  triangular  surface  which  supports 
the  lumbo-sacral  nerve  and  psoas  magnus  muscle.  Immediately 
behind  the  vertebral  articular  surface  is  the  triangular  entrance  of 
the  sacral  canal;  and  on  each  side  of  this  opening  an  articular 
process,  which  looks  backwards^  and  inwards,  like  the  superior  ar- 

Fig.  8.  The  sacrum  seen  upon  its  anterior  surface.  1, 1.  Tiie  transverse  lines  marking 
the  original  constitution  of  the  bone  of  four  pieces.  2,  2.  The  anterior  sacral  foramina. 
3.  The  promontory  of  the  sacrum.  4.  The  ear-shaped  surface  which  articulates  with 
the  ilium.  5.  The  sharp  edge  to  which  the  sacro-ischiatic  ligaments  are  attached.  6. 
The  vertebral  articular  surface.  7.  The  broad  triangular  surface  which  supports  the 
psoas  muscle  and  lumbo-sacral  nerve.  8.  The  articular  process  of  the  right  side.  9. 
The  inferior  extremity,  or  apex  of  the  sacrum.  10.  One  of  the  sacral  cornua.  11.  The 
notch  which  is  converted  into  a  foramen  by  the  coccyx. 

5 


50 


BONES  OF  THE  CRANIUM. 


ticular  processes  of  the  lumbar  vertebrae.  In  front  of  each  articular 
process  is  an  intervertebral  notch.  The  inferior  extremity  presents 
a  small  oval  surface  which  articulates  with  the  coccyx ;  and  on 
each  side  a  notch,  which  with  a  corresponding  notch  in  the  upper 
border  of  the  coccyx  forms  the  foramen  for  the  transmission  of  the 
fifth  sacral  nerve. 

Developement. — By  twenty-one  points  of  ossification  ;  five  for  each 
of  the  three  first  pieces,  viz. — one  for  the  body,  one  for  each  lateral 
portion,  and  one  for  each  lamina ;  and  three  for  each  of  the  two 
last,  viz. — one  for  the  body,  and  one  for  each  lateral  portion. 

Articulations. — With  four  bones ;  the  last  lumbar  vertebra,  ossa 
innominata  and  coccyx. 

Attachment  of  Muscles. — To  seven  pairs  ;  in  front  the  pyriformis, 
on  the  side  the  coccygeus,  and  behind  the  gluteus  maximus,  latissi- 
mus  dorsi,  longissimus  dorsi,  sacro-lumbalis,  and  multifidus  spinas. 

The  Coccyx  (xo'xxuI  cuckoo,  from  resembling  a  cuckoo's  beak)  is 
composed  of  four  small  pieces,  which  form  the  caudal  termination 
of  the  vertebral  column.  The  superior  piece  is  broad,  and  expands 
laterally  into  two  transverse  processes :  it  is  surmounted  by  an  oval 
articular  surface  and  two  cornua  ;  the  former  to  articulate  with  the 
apex  of  the  sacrum,  and  the  latter  with  the  sacral  cornua.  The 
three  latter  pieces  diminish  in  size  from  above  downwards,  and  are 
frequently  consolidated  into  a  single  bone. 

Developement. — ^y  four  centres,  one  for  each  piece. 

Articulations. — With  the  sacrum. 

Attachment  of  Muscles. — To  three  pairs,  and  one  single  muscle : 
gluteus  maximus,  coccygeus,  posterior  fibres  of  the  levator  ani  and 
sphincter  ani. 

OF    THE    SKULL. 

The  skull,  or   superior  expan- 
sion of  the  vertebral  column,  is 
divisible    into    two    parts,  —  the 
cranium  and  the  face ;  the  former 
being  adapted  by  its  form,  struc- 
a     ture,  and  strength  to  contain  and 
^   protect  the  brain,  and  the  latter 
"(A  the  chief  organs  of  sense. 


'» 


The  Cranium  is  composed  of 


#/  '''eight  separate  bones;  viz.  the  oc- 
■^      cipital,  two  parietal,  frontal,  two 
temporal,  sphenoidal,  ethmoidal. 

Occipital  Bone. — This  bone  is 
situated  at  the  posterior  part  and 
base  of  the  cranium.  It  is  trapezoid 
in  form,  and  divisible  into  two  sur- 
faces, four  borders,  and  four  angles. 

Fig.  9.  The  external  surface  of  the  occipital  bone.  1.  The  superior  semicircular  ridge. 
2.  The  occipital  protuberance.     3.  The  spine.     4.  The  inferior  semicircular  ridge.     5. 


OCCIPITAL  BONE,  51 

External  Surface. — Crossing  the  middle  of  the  bone  transversely, 
from  one  lateral  angle  to  the  other,  is  a  prominent  ridge,  the  superior 
semicircular  ridge.  In  the  middle  of  the  ridge  is  a  projection,  called 
the  occipital  protuberance ;  and  descending  from  it  a  small  vertical 
ridge,  the  spine.  Above  and  below  the  superior  semicircular  ridge  the 
surface  is  rough,  for  the  attachment  of  muscles.  About  three-quarters 
of  an  inch  below  this  line  is  another  transverse  ridge,  the  inferior 
semicircular  ridge,  and  beneath  the  latter,  the  foramen  magnum. 
On  each  side  of  the  foramen  magnum,  nearer  to  its  anterior  than  its 
posterior  segment,  and  encroaching  somewhat  upon  the  opening,  is 
an  oblong,  articular  surface — the  condyle,  for  articulation  with  the 
atlas.  The  condyles  approach  towards  each  other  anteriorly,  and 
their  articular  sui'faces  look  downwards  and  outwards.  Directly 
behind  each  condyle  is  an  irregular  fossa,  and  a  small  opening,  the 
posterior  condyloid  foramen  for  the  transmission  of  a  vein  to  the 
lateral  sinus.  In  front  of  the  condyle  is  the  anterior  condyloid  foramen, 
for  the  hypoglossal  nerve  ;  and  on  each  side  of  each  condyle  a  pro- 
jecting ridge,  the  transverse  process,  excavated  in  front  by  a  notch 
which  forms  part  of  the  jugular  foramen.  In  front  of  the  foramen 
magnum  is  a  thick  square  mass,  the  basilar  process,  and  in  the  centre 
of  the  basilar  process  a  small  tubercle  for  the  attachment  of  the 
superior  and  middle  constrictor  muscles  of  the  pharynx. 

Internal  Surface. — Upon  the  internal  surface  is  a  crucial  ridge, 
which  divides  the  bone  into  four  fossae ;  the  two  superior  or  cerebral 
foss«  lodging  the  posterior  lobes  of  the  cerebrum ;  and  the  two  in- 
ferior or  cerebellar,  the  lateral  lobes  of  the  cerebellum.  The  superior 
arm  of  the  crucial  ridge  is  grooved  for  the  superior  longitudinal 
sinus,  and  gives  attachment  to  the  falx  cerebri ;  the  inferior  arm  is 
sharp  and  prominent,  for  the  attachment  of  the  falx  cerebelli,  and 
slightly  grooved,  for  the  two  occipital  sinuses.  The  transverse 
ridge  gives  attachment  to  the  tentorium  cerebelli,  and  is  deeply 
grooved,  for  the  lateral  sinuses.  At  the  point  of  meeting  of  the  four 
arms,  is  a  projection,  the  internal  occipital  p'otuberance,  which  cor- 
responds with  the  similar'process  situated  upon  the  external  surface 
of  the  bone.  The  convergence  of  the  four  grooves  forms  a  slightly 
depressed  fossa,  upon  which  rests  the  torcular  Herophili.  In  the 
centre  of  the  basilar  portion  of  the  bone  is  the  foramen  magnum, 
oblong  in  form  and  larger  behind  than  before,  transmitting  the  spinal 
cord,  spinal  accessory  nerves,  and  vertebral  arteries.  Upon  the 
lateral  margins  of  the  foramen  magnum  are  two  rough  eminences, 
which  give  attachment  to  the  odontoid  ligaments,  and  immediately 
above  these  the  openings  of  the  anterior  condyloid  foramina.     In 

The  foramen  magnum.  6.  The  condyle  of  the  right  side.  7.  The  posterior  con- 
dyloid fossa,  in  which  the  posterior  condyloid  foramen  is  found.  8.  The  anterior  con- 
dyloid foramen  concealed  by  the  margin  of  the  condyle.  9.  The  transverse  process; 
this  process  upon  the  internal  surface  of  the  bone  forms  the  jugular  eminence.  10. 
The  notch  in  front  of  the  jugular  eminence  which  forms  part  of  the  jugular  foramen. 
11.  The  basilar  process.  12,  12.  The  rough  projections  into  which  the  odontoid  liga- 
ments  are  inserted.    13  and  14.  Serrated  borders  of  the  bone. 


52 


OCCIPITAI.  BONE. 


Fig.  10. 


front  of  the  foramen  magnum 
is  the  basilar  process,  grooved 
on  its  surface,  for  supporting  the 
medulla  oblongata  ;  and  on  each 
side  of  the  foramen  a  groove, 
for  the  termination  of  the  lateral 
sinus ;  a  smooth  surface  which 
forms  part  of  the  jugular  fossa  ; 
and  a  projecting  process  which 
divides  the  two  and  is  called  the 
jugular  eminence.  Into  the  jugu- 
lar fossa  will  be  seen  opening 
the  posterior  condyloid  foramen. 
The  superior  borders  are 
very  much  serrated  and  assist 
in  forming  the  lambdoidal  suture ; 
the  inferior  are  rough,  but  not 
serrated,  and  articulate  with  the 
mastoid  portion  of  the  temporal 
bone  by  means  of  the  addita- 
iJientum  suturae  lambdoidalis.  The  jugular  eminence  and  the  side 
of  the  basilar  process  articulate  with  the  petrous  portion  of  the  tem- 
poral bone,  and  the  intermediate  space,  which  is  irregularly  notched, 
forms  the  posterior  boundary  of  the  jugular  foramen,  or  foramen 
lacerum  posterius. 

The  angles  of  the  occipital  bone,  are  the  superior,  inferior,  and 
two  lateral.  The  superior  angle  is  received  into  the  interval  formed 
by  the  union  of  the  posterior  and  superior  angles  of  the  parietal 
bones,  and  corresponds  with  that  portion  of  the  fcetal  head  which  is 
called  the  posterior  fontanelle.  The  inferior  angle  is  the  articular 
extremity  of  the  basilar  process.  The  lateral  angles  at  each  side 
project  into  that  interval  formed  by  the  articulation  of  the  posterior 
and  inferior  angle  of  the  parietal  with  the  mastoid  portion  of  the 
temporal  bone. 

Developement. — By  four  centres ;  one  (sometimes  two)  for  the 
posterior  portion,  one  for  each  condyle,  and  one  for  the  basilar  pro- 
cess. 

Jlrticulations. — With  six  bones;  two  parietal,  two  temporal,  sphe- 
noid, and  atlas. 
Attachment  of  Muscles. — To  thirteen  pairs  ;  to  the  rough  surface 


Fig.  10.  The  internal  surface  of  the  occipital  bone.  1.  The  left  cerebral  fossa.  2.  The 
left  cerebellar  fossa.  3.  The  groove  for  the  posterior  part  of  the  superior  longitudinal 
sinus.  4.  The  spine  for  the  falx  cerebelli,  and  groove  for  the  occipital  sinus.  5.  The 
groove  for  the  left  lateral  sinus.  6.  The  internal  occipital  protuberance  which  lodges 
the  torcular  Herophili.  7.  The  foramen  magnum.  8.  The  basilar  process,  grooved  for 
the  medulla  oblongata.  9.  The  termination  of  the  groove  for  the  lateral  sinus,  bounded 
externally  by  the  jugular  eminence.  10.  The  jugular  fossa  ;  this  fossa  is  completed  by 
the  petrous  portion  of  the  temporal  bone.  11.  The  superior  border  of  the  bone.  12. 
The  inferior  border.  13.  The  border  which  articulates  with  the  petrous  pprtion  of  the 
temporal  bone.    14.  The  anterior  condyloid  foramen, 


PARIETAL   BONE.  53 

above  the  superior  semicircular  ridge,  the  occipito-frontalis ;  to  the 
superior  semicircular  ridge,  the  trapezius  and  sterno-mastoid  ;  to  the 
rough  space  between  the  ridges,  complexus  and  splenius  capitis ;  to 
the  space  between  the  inferior  semicircular  ridge  and  the  foramen 
magnum,  the  rectus  posticus  major  and  minor,  and  obliquus  supe- 
rior; to  the  transverse  process,  the  rectus  lateralis;  and  to  the 
basilar  process,  the  rectus  anticus  major  and  minor,  and  superior 
and  middle  constrictor  muscles. 

Parietal  Bone.  —  The  pa-  ^^" 

rietal  bone  is   situated   at   the 
side  and  vertex  of  the  skull ;  it  ,_^-   "^ 

is  quadrilateral  in  form,  and  di-  /^"'^ 

visible  into  an  external  and  in-        / 
ternal  surface,  four  borders  and      | 
four  angles.  The  superior  border      f  ^^^„  ////  n  '"' 
is  straight,  to  articulate  with  its    ^^'■'"      ,  niiiin  i 
fellow  of  the  opposite  side.  The    /  ^,i  ' 
inferior  border  is   arched   and    %'       ii 
thin,  to  articulate  with  the  tem-     ■^,:ij||"'      ' 
poral  bone.  The  anterior  border     ^, 
is  concave,  and   the  posterior    ^  '-'     ^ 
somewhat  convex. 

External  Surface. — Crossing  the  bone  in  a  longitudinal  direction 
from  the  anterior  to  the  posterior  border,  is  an  arched  line,  the 
temporal  ridge,  to  which  the  temporal  fascia  is  attached.  In  the 
middle  of  this  line,  and  nearly  in  the  centre  of  the  bone,  is  the  pro- 
jection called  the  parietal  boss  or  eminence,  which  marks  the  centre 
of  ossification.  Above  the  temporal  ridge  the  surface  is  rough,  and 
covered  by  the  aponeurosis  of  the  occipito-frontalis;  below  the 
ridge  the  bone  is  smooth  for  the  attachment  of  the  fleshy  fibres  of 
the  temporal  muscle.  Near  the  superior  border  of  the  bone,  and 
at  about  one-third  from  its  posterior  extremity,  is  the  parietal  fora- 
men, which  transmits  a  vein  to  the  superior  longitudinal  sinus. 

Internal  Surface. — The  internal  table  is  smooth,  and  marked 
over  every  part  of  its  surface  by  numerous  furrows,  which  cor- 
respond with  the  ramifications  of  the  arteria  meningea  magna. 
Along  the  upper  border  is  part  of  a  shallow  groove,  completed  by 
the  opposite  parietal  bone,  which  serves  to  contain  the  superior 
longitudinal  sinus.  Some  slight  pits  are  also  observable  near  to  this 
groove,  which  lodge  the  glandulse  Pacchioni. 

The  anterior  inferior  angle  is  thin  and  lengthened,  and  articu- 
lates with  the  greater  wing  of  the  sphenoid  bone.  Upon  its 
inner  surface  it  is  deeply  channelled  by  a  groove  for  the  trunk  of 

Fig.  11.  The  external  surface  of  the  left  parietal  bone.  l.The  superior  or  sagittal  bor- 
der. 2.  The  inferior  or  squamous  border.  3.  The  anterior  or  coronal  border.  4.  The  pos- 
terior or  lambdoidal  border.  5.  The  temporal  ridge;  the  figure  is  situated  immediately 
in  front  of  the  parietal  eminence.  6.  The  parietal  foramen,  unusually  large  in  the 
bone  from  which  this  figure  was  drawn.  7.  The  anterior  inferior  or  elongated  angle. 
S.  The  posterior  inferior  or  truncated  angle. 

5* 


54 


PAKIETAL  BONE. 


the  arteria  meningea  magna.     This  groove  is  frequently  converted 

into  a  canal.     The  posterior  in- 
^^'     '  ferim-  angle  is  thick,  and  pre- 

sents   a    broad    and     shallow 
groove  for  the  lateral  sinus. 

Developement. — By  a  single 
centre. 

Articulations.  —  With  jive 
bones  ;  with  the  opposite  parie- 
tal bone,  the  occipital,  frontal, 
temporal,  and  sphenoid. 

Attackment  of  Muscles. — To 
one  only, — the  temporal.  The 
occipito-frontalis  glides  over  its 
upper  surface. 

Frontal  Bone. — The  frontal 
bone  bears  some  resemblance 
in  form  to  the  under  valve  of  a  scallop  shell.  It  is  situated  at  the 
anterior  part  of  the  cranium,  forming  the  forehead,  and  assists  in 
the  construction  of  the  roof  of  the  orbits  and  nose.  Hence  it  is 
divisible  into  a  superior  or  frontal  portion,  and  an  inferior  or  orbito- 
nasal portion.  Each  of  these  portions  presents  for  examination  an 
external  and  internal  surface,  borders  and  processes. 

External  Surface. — At  about  the  middle  of  each  lateral  half  of  the 
frontal  portion  is  a  projection,  the  frontal  boss  or  eminence,  which 
denotes  the  situation  of  the  centre  of  ossification.  Below  these 
points  are  the  superciliary  ridges,  large  towards  their  inner  termina- 
tion, and  becoming  gradually  smaller  as  they  arch  outwards ;  they 
support  the  eyebrows.  Beneath  the  superciliary  ridges  are  the 
sharp  and  prominent  arches  which  form  the  upper  margin  of  the 
orbits,  the  supra-orbital  ridges.  Externally  the  supra-orbital  ridge 
terminates  in  the  external  angular  process,  and  internally  in  the 
internal  angular  process ;  at  the  inner  third  of  this  ridge  is  a  notch, 
sometimes  converted  into  a  foramen,  the  supra-orbital  notch,  which 
gives  passage  to  the  supra-orbital  or  frontal  artery,  veins,  and 
nerve.  Between  the  two  superciliary  ridges  is  a  rough  projection, 
the  nasal  tuberosity :  the  whole  of  this  portion  of  the  bone  is  some- 
what prominent,  and  denotes  the  situation  of  the  frontal  sinuses. 
Extending  upwards  and  backwards  from  the  external  angular  pro- 
cess is  a  sharp  ridge,  the  commencement  of  the  temporal  ridge,  and 
beneath  this  a  depressed  surface  that  forms  part  of  the  temporal 
fossa. 


Fig.  12.  The  internal  surface  of  the  left  parietal  bone.  1.  The  superior,  or  sagittal 
border.  2.  The  inferior,  or  squamous  border.  3.  l^he  anterior,  or  coronal  border,  4.  The 
posterior,  or  lambdoidal  border.  .5.  Part  of  the  groove  for  the  superior  longitudinal 
sinus.  6.  The  internal  termination  of  the  parietal  foramen.  7.  The  anterior  inferior 
angle  of  the  bone,  on  which  is  seen  the  groove  for  the  trunk  of  the  arteria  meningea 
magna,  8.  The  posterior  inferior  angle,  upon  which  is  seen  a  portion  of  the  groove 
for  the  lateral  sinus. 


FRONTAL  BONE. 


65 


The  orhito-nasal  portion  of  the  bone  consists  of  two  thin  processes, 
the  orbital  plates,  which  form  the  roof  of  the  orbits,  and  of  an  inter- 
vening notch  which  lodges  the  ethmoid  bone,  and  is  called  the 
ethmoidal  fissure.  The  edges  of  the  ethmoidal  fissure  are  hollowed 
into  cavities,  which,  by  their 
union  with  the  ethmoid   bone,  Fig.  13. 

complete  the  ethmoidal  cells ; 
and,  crossing  these  edges  trans- 
versely, are  two  small  grooves, 
sometimes  canals,  which  open 
into  the  orbit  by  the  anterior 
and  posterior  ethmoidal  fora- 
mina. At  the  anterior  termi- 
nation of  these  edges,  are  the 
irregular  openings  which  lead 
into  the  frontal  sinuses  ;  and  be- 
tween the  two  internal  angular 
processes  is  a  rough  excavation 
which  receives  the  nasal  bones, 
and  a  projecting  process,  the 
nasal  spine.  Upon  each  orbital 
plate,  immediately  beneath  the 

external  angular  process,  is  a  shallow  depression  which  lodges  the 
lachrymal  gland  ;  and  beneath  the  internal  angular  process  a  small 
pit,  sometimes  a  tubercle,  to  which  the  cartilaginous  pulley  of  the 
superior  oblique  muscle  is  attached. 

Internal  Surface. — Along  the  middle  line  of  this  surface  is  a 
grooved  ridge,  the  edges  of  the  ridge  giving  attachment  to  the  falx 
cerebri  and  the  groove  lodging  the  superior  longitudinal  sinus.  At 
the  commencement  of  the  ridge  is  an  opening,  sometimes  completed 
by  the  ethmoid  bone,  the  foramen  ccBcum.  This  opening  lodges  a 
process  of  the  dura  mater,  and  occasionally  gives  passage  to  a 
small  vein  which  communicates  with  the  nasal  veins.  On  each  side 
of  the  vertical  ridge  are  some  slight  depressions  which  lodge  the 
glandulas  Pacchioni,  and  on  the  orbital  plates  a  number  of  irre- 
gular pits  called  digital  fossce,  which  correspond  with  the  convolu- 
tions of  the  anterior  lobes  of  the  cerebrum.  The  superior  border  is 
thick  and  strongly  serrated,  bevelled  at  the  expense  of  the  internal 
table  in  the  middle,  where  it  rests  upon  the  junction  of  the  two 
parietal,  and  at  the  expense  of  the  external  table,  on  each  side, 
where  it  receives  the  lateral  pressure  of  those  bones.     The  infe- 


Fig.  13.  The  external  surface  of  the  frontal  bone.  1.  The  situation  of  the  frontal  emi- 
nence  of  the  right  side.  2.  The  superciliary  ridge.  3.  The  supra-orbital  ridge.  4. 
The  external  angular  process.  5.  The  internal  angular  process.  6.  The  supra-orbital 
notch  for  the  transmission  of  the  supra-orbital  nerve,  and  artery ;  in  the  fig-ure  it  is 
almost  converted  into  a  foramen  by  a  small  spiculum  of  bone.  7.  The  nasal  tubero- 
sity ;  the  swelling  around  this  point  denotes  the  situation  of  the  frontal  sinuses.  8. 
The  temporal  ridge  commencing  from  the  external  angular  process  (4).  Tlie  depres 
sionin  which  the  figute  8  is  situated  is  a  part  of  the  temporal  fossa.  9.  The  nasal  spine. 


56 


TEMPORAL  BONE. 


Fiff.  14. 


^Ti^.v 


rio7'  border  is  thin,  irregular, 
and  squamous,  and  articulates 
with  the  sphenoid  bone. 

Develo-pement. — By  two  cen- 
tres, one  for  each  lateral  half. 

Articulations. — With     twelve 

bones ;    the   two   parietal,  the 

\  sphenoid,  ethmoid,  two  nasal, 

two   superior    maxillary,   two 

lachrymal,  and  two  malar. 

Mtackment  of  Muscles. — To 
four  pairs ;  occipito-frontalis, 
orbicularis  palpebrarum,  cor- 
rugator  supercilii,  and  tem- 
poral. 

Temporal  Bone. — The  tem- 
poral bone  is  situated  at  the  side 
and  base  of  the  skull,  and  is  di- 
visible into  a  squamous,  mastoid,  and  petrous  portion. 

The  Squamous  j)ortion,  forming  the  anterior  part  of  the  bone,  is 
thin,  translucent,  and  contains  no  diploe.  Upon  its  external  surface 
it  is  smooth,  to  give  attachment  to  the  fleshy  fibres  of  the  temporal 
muscle,  and  has  projecting  from  it  an  arched  and  lengthened  pro- 
cess, the  zygoma.  Near  the  commencement  of  the  zygoma  upon 
its  lower  border,  is  a  projection  called  the  tubercle,  to  which  is  at- 
tached the  external  lateral  ligament  of  the  lower  jaw,  and  con- 
tinued horizontally  inwards  from  the  tubercle  a  rounded  eminence, 
the  eminentia  articularis.  The  process  of  bone  which  is  con- 
tinued from  the  tubercle  of  the  zygoma  into  the  eminentia  arti- 
cularis is  the  inferior  root  of  the  zygoma.  The  suj)erior  root  is 
continued  upwards  from  the  upper  border  of  the  zygoma,  and 
forms  the  posterior  part  of  the  temporal  ridge,  serving  by  its  pro- 
jection to  mark  the  division  of  the  squamous  from  the  mastoid 
portion  of  the  bone ;  and  the  middle  root  is  continued  directly 
backwards,  and  terminates  abruptly  at  a  narrow  fissure — the  fis- 
sura  Glaseri  or  glenoid  fissure.  The  internal  surface  of  the  squa- 
mous portion  is  marked  by  several  shallow  fossae,  which  correspond 
with  the  convolutions  of  the  cerebrum,  and  by  a  furrow  for  the  posr 


Fig.  14.  The  internal  surface  of  the  frontal  bone  ;  the  bone  is  raised  in  such  a  manner 
as  to  show  the  orbito-nasal  portion.  1.  The  grooved  ridge  for  the  lodgment  of  the  supe- 
rior longitudinal  sinus  and  attachment  of  the  falx.  2.  The  foramen  csecum.  3.  The  su- 
perior  or  coronal  border  of  the  bone ;  the  figure  is  situated  near  that  part  which  is 
bevelled  at  the  expense  of  the  internal  table.  4,  The  inferior  border  of  the  bone.  5. 
The  orbital  plate  of  the  left  side.  6.  The  cellular  border  of  the  ethmoidal  fissure.  The 
foramen  ca3cum  (2)  is  seen  through  the  ethmoidal  fissure.  7.  The  anterior  and  pos- 
terior ethmoidal  foramina ;  the  anterior  seen  leading  into  its  canal.  8.  The  nasal  spine. 

9.  The  depression  within  the  external  angular  process  (12)  for  the  lachrymal  gland. 

10.  The  depression  for  the  pulley  of  the  superior  oblique  muscle  of  the  eye  ;  immedi- 
ately to  the  left  of  this  number  is  the  supra-orbital  notch,  and  to  its  right  the  internal 
angular  process.  II.  The  opening  leading  into  the  frontal  sinuses.  The  same  parts 
are  seen  upon  the  opposite  side  of  the  figure.     12.  The  external  angular  process. 


TEMPORAL  BONE.  57 

terior  branch  of  the  arteria  meningea  magna.     The  superior  or 

squamous  border,  is  very  thin  and  bevelled  at  the  expense  of  the 

inner  surface,  so  as  to  overlap  the  lower  and  arched  border  of  the 

parietal  bone.  The  inferior  border 

is  thick  and  dentated  to  articulate  Fig- 15. 

with  the   spinous  process  of  the 

sphenoid  bone. 

The  Mastoid  portion  forms  the 
posterior  part  of  the  bone  ;  it  is 
thick  and  hollowed  between  its 
tables  into  a  loose  and  cellular 
diploe.  Upon  its  external  surface 
it  is  rough  for  the  attachment  of 
muscles,  and  contrasts  strongly 
with  the  smooth  and  polished-like 
surface  of  the  squamous  portion  ; 
every  part  of  this  surface  is  pierced 
by  small  foramina,  which  give  pas- 
sage to  minute  arteries  and  veins ; 
one  of  these  openings,  oblique  in  its  direction,  of  large  size,  and 
situated  near  the  posterior  border  of  the  bone,  the  mastoid  foramen, 
transmits  a  vein  to  the  lateral  sinus.  This  foramen  is  not  unfre- 
quently  situated  in  the  occipital  bone.  The  inferior  part  of  this  por- 
tion is  round  and  expanded — the  mastoid  process — and  excavated  in 
its  interior  into  numerous  cells,  which  form  a  part  of  the  organ  of 
hearing.  In  front  of  the  mastoid  process  and  between  the  superior 
and  middle  roots  of  the  zygoma,  is  the  large  oval  opening  of  the 
meatus  audiiorius  externus,  surrounded  by  a  rough  lip,  the  -processus 
auditorius.  Directly  to  the  inner  side,  and  partly  concealed  by  the 
mastoid  process,  is  a  deep  groove,  the  digastric  fossa  ;  and  a  little 
more  internally  the  occipital  groove,  which  lodges  the  occipital 
artery.  Upon  its  internal  surface  the  mastoid  portion  presents  a 
broad  and  shallow  groove  for  the  lateral  sinus,  and  terminating  in 
this  groove  the  internal  opening  of  the  mastoid  foramen.  The  supe- 
rior border  of  the  mastoid  portion  is  dentated,  and  its  posterior  bor- 
der thick  and  less  serrated  for  articulation  with  the  inferior  border 
of  the  occipital  bone. 

The  Petrous  portion  of  the  temporal  bone  is  named  from  its  ex- 
treme hardness  and  density.  It  is  a  three-sided  pyramid,  projecting 
horizontally  forwards  into  the  base  of  the  skull,  the  base  being 

Fig.  15.  The  external  surface  of  the  temporal  bone  of  the  left  side.  1.  The  squamous 
portion.  2.  The  mastoid  portion.  3.  The  extremity  of  the  petrous  portion.  4.  The 
zygoma.  5.  Indicates  the  tubercle  of  the  zygoma,  and  at  the  same  time  its  anterior 
I'oot  turning  inwards  to  form  the  eminentia  artieularis.  6.  The  superior  root  of  the 
zygoma,  forming  the  posterior  part  of  the  temporal  ridge.  7.  The  middle  root  of  the 
zygoma  terminating  abruptly  at  the  glenoid  fissure.  8.  The  mastoid  foramen.  9.  The 
meatus  auditorius  externus,  surrounded  by  the  processiis  auditorius.  10.  The  digastric 
fossa,  situated  immediately  to  the  inner  side  of  (2)  the  mastoid  process.  11.  The  sty- 
loid process.  12.  The  vaginal  process.  13.  The  glenoid  or  Glaserian  fissure ;  the 
leading  line  from  this  number  crosses  the  rough  posterior  portion  of  the  glenoid  fossa. 
14.  The  opening  and  part  of  the  groove  for  the  Eustachian  tube. 


58 


TEMPOKAL  BONE. 


Fig.  16. 


applied  against  the  internal  surface  of  the  squamous  and  mastoid 
portions,  and  the  apex  being  received  into  the  triangular  interval 
between  the  spinous  process  of  the  sphenoid  and  basilar  process  of 
the  occipital  bone.  For  convenience  of  description  it  is  divisible 
into  three  surfaces — anterior,  posterior,  and  basilar  ;  and  three  bor- 
ders— superior,  anterior,  and  posterior. 

Surfaces. — The  anterior  surface,  forming  the  posterior  boundary 

of  the  middle  fossa  of  the  interior 
of  the  base  of  the  skull,  presents 
for  examination  from  base  to  apex, 
first  an  eminence  caused  by  the 
projection  of  the  perpendicular  se- 
micircular canal;  next,  a  groove 
leading  to  an  irregular  oblique 
opening — the  hiatus  Fallopii — for 
the  transmission  of  the  petrosal 
branch  of  the  Vidian  nerve  ;  third- 
ly, another  and  smaller  oblique 
foramen,  immediately  beneath  the 
preceding,  for  the  passage  of  the 
nervus  petrosus  superficialis  minor 
— a  branch  of  Jacobson's  nerve ; 
and  lastly  a  large  foramen  near  the  apex  of  the  bone,  the  termina- 
tion of  the  carotid  canal. 

The  posterior  surface  forms  the  front  boundary  of  the  posterior 
fossa  of  the  base  of  the  skull ;  near  its  middle  is  the  oblique  entrance 
of  the  meatus' auditorius  internus.  The  meatus  pursues  a  course 
directly  outwards ;  it  is  about  one-third  of  an  inch  in  length,  and 
terminates  in  two  deep  depressions  (nearly  one-eighth  of  an  inch  in 
depth)  separated  by  a  sharp,  horizontal  ridge.  The  superior  depres- 
sion, the  smaller  of  the  two,  is  divided  at  its  extremity,  by  a  vertical 
ridge,  into  an  anterior  portion,  which  is  the  commencement  of  the 
aquffiductus  Fallopii,  for  the  transmission  of  the  facial  nerve;  and 
a  posterior  portion  which  corresponds  with  the  upper  part  of  the 
inner  wall  of  the  vestibule,  and  is  pierced  by  numerous  openings  for 

Fig.  16.  The  left  temporal  bone,  seen  from  within.  1.  The  squamous  portion.  2.  The 
mastoid  portion.  The  number  is  placed  immediately  above  the  inner  opening  of  the 
mastoid  foramen.  3.  The  petrous  portion.  4.  The  groove  for  the  posterior  branch 
of  the  arteria  meningea  magna.  5.  The  bevelled  edge  of  the  squamous  border  of  the 
bone.  6.  The  zygoma.  7.  Tiie  digastric  fossa  immediately  internal  to  the  mastoid 
prdcess.  8.  The  occipital  groove.  9.  The  groove  for  the  lateral  sinus.  10.  The  ele- 
vation upon  the  anterior  surface  of  the  petrous  bone  marking  the  situation  of  the  per- 
pendicular semicircular  canal.  11.  Tlie  opening  of  termination  of  the  carotid  canal, 
12.  The  meatus  auditorius  internus.  1.3.  A  dotted  line  leads  upwards  from  this  number 
to  the  narrow  fissure  which  lodges  a  process  of  the  dura  mater.  Another  line  leads 
downwards  to  the  sharp  edge  wliich  conceals  the  opening  of  tlie  aquoeductus  coehlcsB, 
while  the  number  itself  is  situated  on  the  bony  lamina  whicli  overlies  the  opening  of 
the  aquteductus  vestibuli.  14.  The  styloid  process.  15.  The  stylo-mastoid  foramen.  16. 
The  carotid  foramen.  17.  The  jugular  process.  The  deep  excavation  to  the  left  of  tliis 
process  forms  part  of  the  jugular  fossa,  and  tiiat  to  the  right  is  the  groove  for  the  vein 
of  the  cochlea.  18.  The  notch  for  the  fifth  nerve  upon  the  upper  border  of  the  petrous 
bone,  near  to  its  apex.  19.  The  extremity  of  the  petrous  bone  which  gives  origin  to 
the  levator  palati  and  tensor  tympani  muscles. 


TEMPORAL  BONE.  59 

the  passage  of  filaments  of  the  vestibular  nerve.  The  inferior 
depression  terminates  in  two  oval  pits,  which  correspond  with  the 
inferior  part  of  the  inner  wall  of  the  vestibule,  and  are  also  pierced 
with  openings  for  the  passage  of  filaments  of  the  vestibular  nerve. 
Upon  the  anterior  wall  of  the  inferior  depression,  and  near  to  its 
termination,  is  a  spiral  groove,  perforated  by  minute  openings  for 
the  passage  of  the  filaments  of  the  cochlear  nerve;  and  in  the 
centre  of  the  spine  is  a  foramen  larger  than  the  rest,  which  leads 
into  the  central  canal  of  the  modiolus,  tuhulus  centralus  modioli. 
This  groove  corresponds  with  the  base  of  the  cochlea,  and  is  termed 
the  tractus  spiralis  foramimdentus.  Upon  the  posterior  wall  of  the 
depression,  and  opposite  to  the  spiral  groove,  is  a  longitudinal 
groove  leading  to  a  foramen  which  transmits  a  considerable  branch 
of  the  vestibular  nerve.  Above  the  meatus  auditorius  internus  is  a 
small  oblique  fissure,  and  a  minute  foramen ;  the  former  lodges  a 
process  of  the  dura  mater,  and  the  foramen  gives  passage  to  a 
small  vein.  Further  outwards,  towards  the  mastoid  portion  of  the 
bone,  is  a  small  slit,  almost  hidden  by  a  thin  plate  of  bone ;  this  is 
the  aqucBductus  vesiibuli,  and  transmits  a  small  artery  and  vein  of 
the  vestibule  and  a  process  of  dura  mater.  Below  the  meatus,  and 
partly  concealed  by  the  margin  of  the  posterior  border  of  the  bone, 
is  the  aquceductus  cochlece,  through  which  passes  a  vein  from  the 
cochlea  to  the  internal  jugular  vein  and  a  process  of  dura  mater. 

The  basilar  surface  is  rough  and  irregular,  and  enters  into  the 
formation  of  the  under  surface  of  the  base  of  the  skull.  Projecting 
downwards,  near  its  middle,  is  a  long  sharp  spine, — the  styloid  pro- 
cess,— occasionally  connected  with  the  bone  only  by  cartilage,  and 
lost  during  maceration,  particularly  in  the  young  subject.'  At  the 
base  of  this  process  is  a  rough  sheath-like  ridge,  into  which  the 
styloid  process  appears  implanted,  the  vaginal  process.  In  front  of 
the  vaginal  process  is  a  broad  triangular  depression,  the  glenoid 
fossa,  bounded  in  front  by  the  eminentia  articularis,  behind  by  the 
vaginal  process,  and  externally  by  the  rough  lip  of  the  processus 
auditorius. 

This  fossa  is  divided  transversely  by  the  glenoid  fissure  (fissura 
Glaseri)  which  lodges  the  extremity  of  the  processus  gracilis  of  the 
malleus,  and  transmits  the  laxator  tympani  muscle,  chorda  tympani 
nerve,  and  anterior  tympanic  artery.  The  surface  of  the  fossa  in 
front  of  this  fissure  is  smooth,  to  articulate  with  the  condyle  of  the 
lower  jaw ;  and  that  behind  the  fissure  is  rough,  for  the  reception 
of  a  part  of  the  parotid  gland.  At  the  extremity  of  the  inner  angle 
of  the  glenoid  fossa  is  the  foramen  for  the  Eustachian  tube ;  and 
separated  from  it  by  a  thin  lamella  of  bone,  called  processus  cochlea- 
riformis,  is  a  small  canal  for  the  transmission  of  the  tensor  tympani 
muscle.  Directly  behind,  and  at  the  root  of  the  styloid  process,  is 
the  stylo-mastoid  foramen,  the  opening  of  exit  to  the  facial  nerve, 
and  of  entrance  to  the  stylo-mastoid  artery.  Nearer  to  the  apex  of 
the  bone  is  a  large  oval  opening,  the  carotid  foramen — the  com- 
mencement of  the  carotid  canal,  which  lodges  the  internal  carotid 
artery  and  the  carotid  plexus.     And  between  the  stylo-mastoid  and 


60  SPHENOIDAL  BONE. 

carotid  foramen  in  the  posterior  border,  is  an  irregular  excavation 
forming  part  of  the  jugular  fossa,  and  divided  into  two  parts  by  a 
ridge  and  a  sharp  spine,  the  jugular  process.  Upon  this  ridge,  at 
the  posterior  margin  of  the  carotid  foramen,  is  a  small  opening 
leading  into  the  canal  which  transmits  the  tympanic  branch  of  the 
glosso-pharyngeal  nerve  (Jacobson's  nerve). 

Borders. — The  superior  border  is  sharp,  and  gives  attachment  to 
the  tentorium  cerebelli.  It  is  grooved  for  the  superior  petrosal 
sinus,  and  near  its  extremity  is  marked  by  a  smooth  notch  upon 
which  reclines  the  fifth  nerve. 

The  anterior  border  is  grooved  for  the  Eustachian  tube,  and 
forms  the  posterior  boundary  of  the  foramen  lacerum  basis  cranii ; 
by  its  sharp  extremity  it  gives  attachment  to  the  tensor  tympani 
and  levator  palati  muscles.  The  posterior  border  is  grooved  for  the 
inferior  petrosal  sinus,  and  excavated  for  the  jugular  fossa ;  it  forms 
the  anterior  boundary  of  the  foramen  lacerum  posterius. 

Developement. — By  five  centres ;  one  for  the  squamous  portion, 
one  for  the  mastoid,  one  for  the  petrous  portion,  one  for  tiie  audi- 
tory process,  and  one  for  the  styloid  pi'ocess. 

Articulations. — With  Jive  bones ;  occipital,  parietal,  sphenoid,  in- 
ferior maxillary,  and  malar. 

Attachment  of  Muscles. — To  fourteen  ;  by  the  squamous  portion, 
to  the  temporal ;  by  the  zygoma,  to  the  masseter ;  by  the  mastoid 
portion,  to  the  occipito-frontalis,  splenius  capitis,  sterno-mastoid, 
trachelo-mastoid,  digastricus  and  retrahens  aurem;  by  the  styloid 
process,  to  the  stylo-pharyngeus,  stylo-hyoideus,  stylo-glossus,  and 
two  ligaments — the  stylo-hyoid  and  stylo-maxillary ;  and  by  the 
petrous  portion,  to  the  levator  palati,  tensor  tympani,  and  stapedius. 

Sphenoidal  Bone. — The  sphenoid  (tfcp^v,  a  wedge)  is  an  irregular 
bone  situated  at  the  base  of  the  skull,  wedged  between  the  other 
bones  of  the  cranium,  and  entering  into  the  formation  both  of  the 
cranium  and  face.  It  bears  some  resemblance  in  form  to  a  bat 
with  its  wings  extended,  and  is  divisible  into  body,  wings,  and  pro- 
cesses. 

The  body  forms  the  central  mass  of  the  bone,  from  which  the 
wings  and  processes  are  projected.  From  the  upper  and  anterior 
part  of  the  body  extend  on  each  side  two  small  triangular  plates, — 
the  lesser  wings ;  from  either  side  and  expanding  laterally  are  the 
greater  wings  ;  proceeding  backwards  from  the  base  of  the  greater 
wings,  the  spinous  processes ;  and  downwards,  the  pterygoid  pro- 
cesses. 

The  body  presents  for  examination  a  superior  or  cerebral  surface, 
an  antero-infcrior  surface,  and  a  posterior  surface. 

Superior  Surface. — At  the  anterior  extremity  of  this  surface  is  a 
small  projecting  plate,  the  ethmoidal  spine,  and  spreading  out  on 
either  side  the  lesser  wings.  Behind  the  ethmoidal  spine  in  the 
middle  line  is  a  rounded  elevation,  the  olivary  process,  which  sup- 
ports the  commissure  of  the  optic  nerves.  Passing  outwards  and 
forwards  from  the  olivary  process,  are  the  optic  foramina,  which 
transmit  the  optic  nerves  and  ophthalmic  arteries.    Behind  the  optic 


SPHENOID  BOI^E. 


61 


foramina  are  two  sharp  tubercles,  the  anterior  clinoid  processes, 
which  are  the  inner  termination  of  the  lesser  wings.  Beneath  these 
processes,  on  the  sides  of  -pj    ^t, 

the  olivary  process,  are 
two  depressions*  for  the 
last  turn  of  the  internal 
carotid  arteries.  Behind 
the  olivary  process,  is  the 
sella  Turcica,  the  deep 
fossa  which  lodges  the 
pituitary  gland  and  cir- 
cular sinus;  behind  and 
somewhat  overhanging 
the    sella    Turcica,    is    a  ,  ° 

broad  rough  plate,  bound- 
ed at  each  angle  by  a  tubercle,  the  posterior  clinoid  processes  ;  and 
behind  this  plate  an  inclining  surface,  which  is  continuous  with  the 
basilar  process  of  the  occipital  bone.  On  either  side  of  the  sella 
Turcica  is  a  broad  groove  {carotid)  which  lodges  the  internal 
carotid  artery,  the  cavernous  sinus,  and  its  nerves.  Immediately 
external  to  this  groove,  at  the  junction  of  the  greater  wings  with 
the  body,  are  four  foramina :  the  first  is  a  broad  interval,  the  sphe- 
noidal fissure,  which  separates  the  greater  and  lesser  wings,  and 
transmits  the  third,  fourth,  the  three  branches  of  the  ophthalmic 
division  of  the  fifth  and  the  sixth  nerves,  and  the  ophthalmic  vein. 
Behind  and  beneath  this  fissure  is  the  foramen  rotundum  for  the 
superior  maxillary  nerve  ;  and  still  farther  back,  in  the  base  of  the 
spinous  process,  the  foramen  ovale  for  the  inferior  maxillary  nerve, 
arteria  meningea  parva,  and  nervus  petrosus  superficialis  minor. 
Behind  the  foramen  ovale,  near  the  apex  of  the  spinous  process,  is 
the  foramen  spinosum  for  the  arteria  meningea  magna. 

Fig.  17.  The  superior  or  cerebral  surface  of  the  sphenoid  bone.  1.  The  processus  oli- 
varis.  2.  The  ethmoidal  spine.  3.  The  lesser  wing  of  the  left  side.  4.  The  cerebral  sur- 
face of  the  greater  wing  of  the  same  side.  5.  The  spinous  process.  6.  The  extremity 
of  the  pterygoid  process  of  the  same  side  projecting  downwards  from  the  under  sur- 
face of  the  body  of  the  bone.  7.  The  foramen  opticum.  8.  The  anterior  clinoid  pro- 
cess. 9.  The  groove  by  the  side  of  the  sella  Turcica;  for  lodging  the  internal  carotid 
artery,  cavernous  plexus,  cavernous  sinus,  and  orbital  nerves.  10.  The  sella  Turcica. 
11.  The  posterior  boundary  of  the  sella  Turcica;  its  projecting  angles  are  the  pos- 
terior clinoid  processes.  12.  The  basilar  portion  of  the  bone.  13.  Part  of  tlie  sphe- 
noidal fissure.  14.  The  foramen  rotundum.  15.  The  foramen  ovale.  16.  The  fora- 
men spinosum.  17.  The  angular  interval  which  receives  the  apex  of  the  petrous  portion 
of  the  temporal  bone.  The  posterior  extremity  of  the  Vidian  canal  terminates  at  this 
angle.  18.  The  spine  of  the  spinous  process  ;  it  atTords  attachment  to  the  internal 
lateral  ligament  of  the  lower  jaw.  19.  The  border  of  the  greater  wing  and  spinous 
process  which  articulates  with  the  anterior  p;irt  of  the  squamous  portion  of  the  tem- 
poral bone.  20.  The  internal  border  of  the  spinous  process,  which  assists  in  the 
formation  of  the  foramen  lacerum  basis  cranii.  21.  That  portion  of  the  greater  ala 
which  articulates  with  the  anterior  inferior  angle  of  the  parietal  bone.  22.  Tlie  por- 
tion of  the  greater  ala,  which  articulates  with  the  orbital  process  of  the  frontal  bone. 

*  These  depressions  are  occasionally,  as  in  a  skull  before  me,  converted  into  fora- 
mina by  tlie  extension  of  a  short  bony  pillar  from  the  anterior  clinoid  process  to  the 
body  of  the  sphenoid. 

6 


62  SPHENOID  BONE. 

Upon  the  antero-inferior  surface  is  a  long  flattened  spine,  the 
rostrum,  which  articulates  with  the  vomer ;  and  on  each  side  of  the 

rostrum  an  irregular  opening, 
leading  into  the  sphenoidal 
cells ;  these  openings  are  par- 
tially closed  by  two  thin  plates 
of  bone  (frequently  broken 
away),  the  sphenoidal  spongy 
bones.  On  each  side  of  the 
sphenoidal  cells  are  the  out- 
lets of  the  optic  foramina, 
sphenoidal  fissures,  and  fora- 
mina rotunda,  the  lesser  and 
greater  wings ;  and  below, 
the  pterygoid  processes. 
Upon  the  under  surface  of  the  body  are  two  small  fissures,  con- 
verted into  canals  by  the  vomer,  the  pterygo-palatine  canals,  which 
transmit  the  pterygo-palatine  arteries ;  and  traversing  the  roots  of 
the  pterygoid  at  their  union  with  the  body,  two  pterygoid  or  Vidian 
canals,  which  give  passage  to  the  Vidian  nerve  and  artery  at  each 
side.  The  posterior  surface  is  flat  and  rough,  and  articulates  with 
the  basilar  process  of  the  occipital  bone.  In  the  adult  this  union  is 
usually  completed  by  bone  ;  from  which  circumstance  the  sphenoid, 
in  conjunction  with  the  occipital,  was  described  by  Soemmering 
and  Meckel  as  a  single  bone,  under  the  name  of  spheno-occipital  or 
basilar  bone.  This  surface  is  continuous  on  each  side  with  the 
spinous  process,  and  at  the  angle  of  union  is  the  termination  of  the 
Vidian  canal  or  foramen  pterygoideum. 

The  lesser  ivings  (processes  of  Ingrassias)  are  thin  and  triangular, 
the  base  being  attached  to  the  upper  and  anterior  part  of  the  body 
of  the  sphenoid,  and  the  apex  extended  outwards,  and  terminating 
in  an  acute  point.  The  anterior  border  is  irregularly  serrated,  the 
posterior  being  free  and  rounded,  and  received  into  the  fissure  of 
Sylvius  of  the  cerebrum.  The  inner  extremity  of  this  border  forms 
the  anterior  clinoid  process,  which  is  supported  by  a  short  pillar  of 
bone,  giving  attachment  to  a  part  of  the  common  tendon  of  the 
muscles  of  the  orbit.  The  lesser  wing  forms  the  posterior  part  of 
the  roof  of  the  orbit,  and  its  base  is  traversed  by  the  optic  foramen. 
The  greater  ivings  present  three  surfaces ;  a  superior  or  cerebral, 
which  forms  part  of  the  middle  fossa  of  the  base  of  the  skull,  an 

Fig.  18.  The  antero-inferior  view  of  the  sphenoid  bone.  1.  The  ethmoid  spine.  2. 
The  rostrum.  3.  The  sphenoidal  spongy  bone,  partly  closing  the  left  opening  of  the 
sphenoidal  cells.*  4.  The  lesser  wing.  5.  The  foramen  opticum  piercing  the  base  of 
the  lesser  wing.  6.  The  sphenoidal  fissure.  7.  The  foramen  rotundum.  8.  The  orbital 
surface  of  the  greater  wing.  9.  Its  temporal  surface.  10.  The  pterygoid  ridge. 
11.  The  pterygo-palatine  canal.  12.  The  foramen  of  entrance  to  the  Vidian  canal. 
13.  The  internal  pterygoid  plate.  14.  The  hamular  process.  15.  The  external 
pterygoid  plate.  16.  The  foramen  spinosum.  17.  Tiie  foramen  ovale.  18.  The 
extremity  of  the  spinous  process  of  the  sphenoid. 

*  This  is  a  part  of  the  pyramid  of  Wistar.     See  description  of  ethmoid. — G. 


SPHENOID  BONE.  63 

anterior  surface  which  assists  in  forming  the  outer  wall  of  the  orbit, 
and  an  external  surface,  divided  into  two  parts  by  the  'pterygoid 
ridge.  The  superior  part  of  the  external  surface  enters  into  the 
formation  of  the  temporal  fossa,  and  the  inferior  portion  forms  part 
of  the  zygomatic  fossa.  The  pterygoid  ridge,  dividing  the  two, 
gives  attachment  to  the  upper  origin  of  the  pterygoideus  externus 
muscle. 

The  spinous  processes  project  backwards  at  each  side  from  the 
base  of  the  greater  wings  of  the  sphenoid,  and  are  received  into  the 
angular  intervals  between  the  squamous  and  petrous  portions  of  the 
temporal  bones.  Piercing  the  base  of  each  process  is  a  large  oval 
opening,  ihe  foramen  ovale  ;  nearer  its  apex  a  smaller  opening,  the 
foramen  spinosum  ;  and  extending  downwards  from  the  apex  a  short 
spine,  which  gives  attachment  to  the  internal  lateral  ligament  of  the 
lower  jaw  and  to  the  laxator  tympani  muscle.  The  external  border 
of  the  spinous  process  is  rough,  to  articulate  with  the  lower  border 
of  the  squamous  portion  of  the  temporal  bone ;  the  internal  forms 
the  anterior  boundary  of  the  foramen  lacerum  basis  cranii,  and  is 
somewhat  grooved  for  the  reception  of  the  Eustachian  tube. 

The  pterygoid  processes  descend  perpendicularly  from  the  base  of 
the  greater  wings,  and  form  in  the  articulated  skull  the  lateral  boun- 
daries of  the  posterior  nares.  Each  process  consists  of  an  external 
and  internal  plate,  and  an  anterior  surface.  The  external  plate  is 
broad  and  thin,  giving  attachment,  by  its  external  surface,  to  the 
external  pterygoid  muscle,  and  by  its  internal  surface  to  the  internal 
pterygoid.  This  plate  is  sometimes  pierced  by  a  foramen,  which  is 
frequently  formed  by  a  process  of  communication  passing  between 
it  and  the  spinous  process.  The  internal  pterygoid  plate  is  long 
and  narrow,  and  terminated  at  its  extremity  by  a  curved  hook,  the 
kamular  process,  around  which  plays  the  tendon  of  the  tensor  palati 
muscle.  At  the  base  of  the  internal  pterygoid  plate  is  a  small 
oblong  depression,  the  scaphoid  fossa,  from  which  arises  the  cir- 
cumflexus,  or  tensor  palati  muscle.  The  interval  between  the 
two  pterygoid  plates  is  the  pterygoid  fossa ;  and  the  two  plates  are 
separated  inferiorly  by  an  angular  notch  {palatine,)  ,which  receives 
the  tuberosity,  or  pterygoid  process,  of  the  palate  bone.  The  ante- 
rior surface  of  the  pterygoid  process  is  broad  near  its  base,  and 
supports  Meckel's  ganglion.  The  base  of  the  process  is  pierced  by 
the  Vidian  canal. 

Devehpement — By  iivelve  centres;  four  for  the  body,  viz.,  two  for 
its  anterior,  and  two  for  its  posterior  part ;  four  for  the  wings ;  two 
for  the  external  pterygoid  plates,  and  two  for  the  sphenoidal  spongy 
bones. 

Articulations. — With  twelve  bones  ;  all  the  bones  of , the  head  and 
five  of  the  face,  viz.  the  two  malar,  two  palate,  and  the  vomer. 

Attachment  of  Muscles. — To  tiveloe  pairs ;  temporal,  external  ptery- 
goid, internal  pterygoid,  superior  constrictor,  tensor  palati,  laxator 
tympani,  levator  palpebrse,  obliquus  superior,  superior  rectus,  internal 
rectus,  inferior  rectus,  and  external  rectus. 


64  ETHMOID  BONE. 

Ethmoid  Boxe. — The  ethmoid  (vj^i^og,  a  sieve)  is  a  square-shaped 
cellular  bone,  situated  between  the  two  orbits,  at  the  root  of  the  nose, 
and  perforated  upon  its  upper  surface  by  a  number  of  small  open- 
ings, from  which  peculiarity  it  has  received  its  name.  It  consists  of 
a  perpendicular  lamella  and  two  lateral  masses. 

The  perpendiculai-  lamella  is  a   thin  central  plate,  which   arti- 
Yig^  19.  culates  with  the  vomer  and  cartilage   of 

3  the  septum,  and  assists  in  forming  the  sep- 

tum of  the  nose.  It  is  surmounted  supe- 
riorly by  a  thick  and  strong  process,  the 
crista  galli,  which  projects  into  the  cavity 
of  the  skull,  and  gives  attachment  to  the 
falx  cerebri.  On  each  side  of  the  crista 
galli,  upon  the  upper  surface  of  the  bone, 
is  a  thin  and  grooved  plate,  perforated  by 
a  number  of  small  openings,  the  cribriform 
lamella,  which  supports  the  bulb  of  the 
olfactory  nerve,  and  gives  passage  to  its 
filaments,  and  to  the  internal  nasal  nerve. 
The  cribriform  lamella  serves  to  connect  the  masses  with  the  per- 
pendicular plate. 

The  lateral  masses  are  divisible  into  an  internal  and  external  sur- 
face, and  four  borders — superior,  inferior,  anterior,  and  posterior. 
The  internal  surface  is  rough  and  slightly  convex,  and  forms  the 
external  boundary  of  the  upper  part  of  the  nasal  fossae.  Towards 
the  posterior  border  of  this  surface  is  a  narrow  horizontal  fissure, — 
the  superior  meatus  of  the  nose, — the  upper  margin  of  which  is  thin, 
and  somewhat  curled  inwards;  hence  it  is  named  the  superior  tur- 
binated bone.  Below  the  meatus  is  the  convex  surface  of  another 
thin  plate  which  is  curled  outwards,  and  forms  the  lower  border  of 
the  mass,  the  middle  turbinated  bone.  The  external  surface  is  quad- 
rilateral and  smooth,  hence  it  is  named  os  planum;  it  enters  into  the 
formation  of  the  inner  wall  of  the  orbit. 

The  superior  border  is  irregular  and  cellular,  the  cells  being  com- 
pleted by  the  edges  of  the  ethmoidal  fissure  of  the  frontal  bone.  This 
border  is  crossed  by  two  grooves,  sometimes  complete  canals,  open- 
ing into  the  orbit  by  the  anterior  and  posterior  ethmoidal  foramina. 
The  inferior  border  is  formed  internally  by  the  lower  border  of  the 
middle  turbinated  bone,  and  externally  by  a   concave    irregular 

Fig.  I'J.  The  etiimoid  bone  seen  from  above  and  behind.  1.  The  central  lamella.  2,  2. 
The  lateral  masses;  the  numbers  are  placed  on  the  posterior  border  of  the  lateral  mass 
at  each  side.  3.  The  crista  galli  process,  4.  The  cribriform  plate  of  the  left,  side 
pierced  by  the  cribriform  foramina.  5.  The  hollow  space  immediately  above  and  to 
the  left  of  tljis  number  is  the  superior  meatus.  6.  The  superior  turbinated  bone.  7. 
The  middle  turbinated  bone  ;  the  numbers  5,  6,  7,  are  situated  upon  the  internal  sur- 
face  of  the  left,  lateral  mass,  near  its  posterior  part.  The  interval  between  these  parts 
is  the  superior  meatus.  8.  The  external  surface  of  the  lateral  mass,  or  os  planum,  9, 
The  superior  or  frontal  border  of  the  lateral  mass,  g-rooved  by  the  anterior  and  poste- 
rior ethmoidal  canals,  10,  Refers  to  the  concavity  of  the  middle  turbinated  bone, 
wijich  is  the  upper  boundary  of  the  middle  meatus. 


NASAL  BONES.  65 

fossa,  the  upper  boundary  of  the  middle  meatus.  The  anterior  border 
presents  a  number  of  incomplete  cells,  which  are  closed  by  the 
superior  maxillary  and  lachrymal  bones;  the  'posterior  border  is 
irregularly  cellular,  to  articulate  with  the  sphenoid  and  palate  bones.* 

The  lateral  masses  are  composed  of  cells,  which  are  divided  by  a 
thin  partition  into  anterior  and  posterior  ethmoidal  cells.  The  ante- 
rior, the  most  numerous,  communicate  with  the  frontal  sinuses,  and 
open  by  means  of  an  irregular  and  incomplete  tubular  canal,  the 
infundibulum,  into  the  middle  meatus.  The  posterior  cells,  fewer  in 
number,  open  into  the  superior  meatus. 

Developement. — By  three  centres  ;  one  for  each  lateral  mass,  and 
one  for  the  perpendicular  lamella. 

Articulations. — With  thirteen  bones;  two  of  the  cranium, — the 
frontal  and  sphenoid ;  the  rest  of  the  face,  viz,  the  nasal,  superior 
maxillary,  lachrymal,  palate,  the  inferior  turbinated,  and  the  vomer. 

No  muscles  are  attached  to  this  bone. 

BONES    OF     THE     FACE. 

The  face  is  composed  of  fourteen  bones  ;  viz.  the 
Two  nasal,  Two  palate. 

Two  superior  maxillary,  Two  inferior  turbinated, 

Two  lachrymal,  Vomer, 

Two  malar,  Inferior  maxillary. 

Nasal  Bones. — The  nasal  (fig.  24)  are  two  small  quadrangular 
bones,  forming  by  their  union  the  bridge  and  base  of  the  nose. 
Upon  the  upper  surface  they  are  convex,  and  pierced  by  a  foramen, 
for  a  small  artery ;  on  the  under  surface  they  are  somewhat  con- 
cave, and  marked  by  a  groove,  which  lodges  the  nasal  branch  of 
the  ophthalmic  nerve.  The  superior  border  is  narrow  and  thick,  the 
inferior  broad,  thin,  and  irregular. 

Developement. — By  a  single  centre  for  each  bone. 

Articulations. — With  four  bones  ;  frontal,  ethmoidal,  nasal,  and 
superior  maxillary. 

Attaclnnent  of  Muscles. — It  has  in  relation  with  it  the  pyramidalis 
nasi,  and  compressor  nasi ;  but  neither  of  these  muscles  is  inserted 
into  it. 

Superior  Maxillarvt  Bones. — The  superior  maxillary  are  the 
largest  bones  of  the  face,  with  the  exception  of  the  lower  jaw  ;  they 
form,  by  their  union,  the  whole  of  the  upper  jaw,  and  assist  in  the 
construction  of  the  nose,  the  orbit,  the  cheek,  and  the  palate.  Each 
bone  is  divisible  into  a  body  and  four  processes. 

*  Mr.  Wilson  has  entirely  omitted  the  description  of  the  pyramids  of  Wistar,  which 
in  their  early  stage  project  as  thin  triangular  lamincE  from  the  posterior  borders  of  the 
lateral  masses.  As  they  become  developed  the  edges  of  the  laminae  fold  over  so  as  to 
form  an  imperfect  triangular  pyramid,  encroaching  upon  the  body  of  the  sphenoid 
bone  on  its  under  surface,  and  finally  coalescing  vi^ith  it  so  as  to  perfect  the  sphenoidal 
cells.  The  remains  of  these  pyramids  may  be  seen  on  the  adult  bone,  and  are  called 
by  Wilson,  the  sphenoidal  spongy  bones.  They  were  first  studied  by  Professor  Wistar, 
and  are  called  after  him. — G. 

6* 


06  SUrEEIOR  MAXILtAEY  BONES. 

The  body  is  triangular  in  form,  and  hollowed  in  its  interior  into 
a  large  cavity,  the  antrum  maxillare  (antrum  of  Highmore).  It 
presents  for  examination  three  sides ;  an  external  or  facial,  internal 
or  nasal,  and  a  posterior  or  zygomatic,  and  a  superior  surface — the 
orbital.  .  The  external  or  facial  surface  forms  the  anterior  part  of 
the  bone  ;  it  is  irregularly  concave,  and  pre- 
^'ff-  20.  sents  a  deep  depression  towards  its  centre, 

— the  canine  fossa,  which  gives  attachment  to 
two  muscles,  the  compressor  nasi  and  levator 
anguli  oris.  Immediately  above  this  fossa 
is  the  infra-orbital  foramen, — the  termination 
of  the  infra-orbital  canal, — transmitting  the 
superior  maxillary  nerve,  and  infra-orbital 
artery  ;  and  above  the  infra-orbital  foramen, 
the  lower  margin  of  the  orbit,  continuous 
externally  with  the  rough  articular  surface 
of  the  malar  process,  and  internally  with  a 
thick  ascending  plate,  the  nasal  process. 
Towards  the  middle  Hne  of  the  face  this 
surface  is  bounded  by  the  concave  border 
of  the  opening  of  the  nose,  which  is  projected  forwards  at  its  in- 
ferior termination  into  a  sharp  process,  forming  with  a  similar  pro- 
cess of  the  opposite  bone,  the  nasal  spine.  Beneath  the  nasal  spine, 
and  above  the  two  superior  incisor  teeth,  is  a  slight  depression,  the 
incisive  or  rnyrtiform  fossa,  which  gives  origin  to  the  depressor  labii 
superioris  alseque  nasi  muscle.  The  rnyrtiform  fossa  is  divided 
from  the  canine  fossa  by  a  perpendicular  ridge,  corresponding  with 
the  direction  of  the  root  of  the  canine  tooth.  The  inferior  boundary 
of  the  facial  surface  is  the  alveolar  process  which  contains  the 
teeth  of  the  upper  jaw,  and  it  is  separated  from  the  zygomatic  sur- 
face by  a  strong  projecting  eminence,  the  malar  process.  The  in- 
ternal, or  nasal  surface,  presents  a  large  irregular  opening,  leading 
into  the  antrum  maxillare;  this  opening  is  nearly  closed  in  the  ar- 
ticulated skull  by  the  ethmoid,  palate,  lachrymal,  and  inferior  turbi- 
nated bones.  The  cavity  of  the  antrum  is  somewhat  triangular, 
corresponding  in  shape  with  the  form  of  the  body  of  the  bone. 
Upon  its  internal  surface  are  numerous  grooves,  lodging  branches 
of  the  superior  maxillary  nerve,  and  projecting  into  its  floor  several 
conical  processes,  corresponding  with  the  roots  of  tlie  first  and 
second  molar  teeth.     In  front  of  the  opening  of  the  antrum  is  the 

FijT.  20.  The  superior  maxillary  bones  of  the  right  side,  as  seen  from  the  lateral  aspect, 
1.  The  external,  oi*  facial  surface  ;  the  depression  in  which  the  figure  is  placed  is  the 
canine  fossa.  2.  The  posterior,  or  zygomatic  surface.  3.  The  superior,  or  orbital  sur- 
face. 4.  The  infra-orbital  foramen  ;  it  is  situntcd  immediately  below  the  number.  5. 
The  infra-orbital  canal,  leading  to  the  infra-orbital  foramen.  G.  The  inferior  border  of 
the  orbit.  7.  The  malar  i)rocc.ss.  8.  The  nasal  process.  9.  The  concavity  forming 
the  lateral  boundary  of  the  anterior  niircs.  10.  The  nasal  spine.  11.  The  incisive,  or 
rnyrtiform  fossa.  12.  The  alveolar  process.  13.  Tlic  internal  border  of  the  orbital 
surfiicc,  which  articulates  with  the  ethmoid  and  palate  bone.  I'l.  The  concavity  which 
articulates  with  tiic  laclirymnl  bone,  ;ind  forms  the  commencement  of  tTw;  nasal  duct. 
15.  The  palate  process,  i.  The  two  incisor  teeth,  c.  'i'hc  canine,  h.  The  two  biscus- 
pidati.     in.  The  three  molares. 


SUPERIOR  MAXILLARY  BONES.  67 

strong  ascending  plate  of  the  nasal  process,  marked  inferiorly  by  a 
rough  horizontal  ridge,  which  gives  attachment  to  the  inferior  tur- 
binated bone.  The  concave  depression  immediately  above  this 
ridge  corresponds  with  the  middle  meatus  of  the  nose,  and  that  below 
the  ridge  with  the  inferior  meatus.  Between  the  nasal  process  and 
the  opening  of  the  antrum,  is  a  deep  groove,  which  is  converted 
into  a  canal  by  the  lachrym>al  bone,  and  constitutes  the  nasal  duct 
or  ductus  ad  nasum.  The  superior  border  of  the  nasal  surface  is 
irregularly  cellular,  and  articulates  with  the  lachrymal  and  ethmoid 
bone ;  the  posterior  border  is  rough,  and  articulates  with  the  palate 
bone;  the  anterior  border  is  sharp,  and  forms  the  free  margin  of  the 
opening  of  the  nose ;  and  from  the  inferior  border  projects  inwards 
a  stroncT  horizontal  plate,  the  palate  process. 

The  posterior  surface  may  be  called  zygomatic,  from  forming  part 
of  the  zygomatic  fossa ;  it  is  bounded  externally  by  the  malar  process, 
and  internally  by  a  roUgh  and  rounded  border,  the  tuberosity, 
which  is  pierced  by  a  number  of  small  foramina,  giving  passage  to 
the  posterior  dental  nerves  and  branches  of  the  superior  dental 
artery.  The  lower  part  of  this  tuberosity  presents  a  rough  oval 
surface  to  articulate  vv'ith  the  palate  bone,  and  immediately  above 
and  to  the  inner  side  of  this  articular  surface  a  smooth  groove, 
which  forms  part  of  the  posterior  palatine  canal.  The  superior 
border  is  smooth  and  rounded  to  form  the  lower  boundary  of  the 
spheno-maxillary  fissure,  and  is  marked  by  a  notch,  the  commence- 
ment of  the  infra-orbital  canal.  The  inferior  boundary  is  the 
alveolar  process,  containing  the  two  last  molar  teeth. 

The  orbital  surface  is  triangular  and  thin,  and  constitutes  the 
floor  of  the  orbit.  It  is  bounded  internally  by  an  irregular  edge, 
which  articulates  with  the  palate,  ethmoid,  and  lachrymal  bone ; 
posteriorly,  by  the  smooth  border  which  enters  into  the  formation 
of  the  spheno-maxillary  fissure;  and  anteriorly,  by  a  convex  mar- 
gin, partly  smooth  and  partly  rough,  the  smooth  portion  forming 
part  of  the  lower  bolder  of  the  orbit,  and  the  rough  articulating 
with  the  malar  bone.  The  middle  of  this  surface  is  channelled  by 
a  deep  groove  and  canal,  the  infra-orbital,  which  terminates  at  the 
infra-orbital  foramen. 

The  four  processes  of  this  bone  are,  the  nasal,  malar,  alveolar, 
and  palate. 

The  nasal  process  ascends  by  the  side  of  the  nose,  to  which  it 
forms  the  lateral  boundary,  and  articulates  with  the  frontal  and 
nasal  bone. 

By  its  external  surface  it  gives  attachment  to  the  levator  labii 
superioris  alasque  nasi,  and  to  the  orbicularis  palpebrarum  muscle; 
its  internal  surface  contributes  to  form  the  inner  wall  of  the  nares, 
and  the  posterior  border  is  thick  and  hollowed  into  a  groove  for  the 
nasal  duct.  The  margin  of  the  nasal  process,  which  is  continuous 
with  the  lov^^er  border  of  the  orbit,  is  sharp  and  marked  by  a  small 
tubercle  which  serves  as  a  guide  to  the  introduction  of  the  knife  in 
the  operation  for  fistula  lachrymalis. 

The  malar  process,  large  and  irregular,  is  situated  at  the  angle 


68  LACHRYMAL  BONES. 

of  separation  between  the  facial  and  zygomatic  surfaces,  and  pre- 
sents a  large  triangular  surface  for  articulation  with  the  malar  bone. 

The  alveolar  'process  forms  the  lower  margin  of  the  bone ;  it  is 
spongy  and  cellular  in  texture,  and  excavated  into  deep  holes  for 
the  reception  of  the  teeth. 

The  -palate  process  is  thick  and  strong,  and  projects  horizontally 
inwards  from  the  inner  surface  of  the  body  of  the  bone.  Superiorly, 
it  is  concave,  and  forms  the  floor  of  the  nares  ;  inferiorly,  it  is  also 
concave,  and  assists  in  the  formation  of  the  roof  of  the  palate. 
Its  internal  edge  is  raised  into  a  ridge,  which,  with  a  corresponding 
ridge  in  the  opposite  bone,  forms  a  groove  for  the  reception  of  the 
vomer.  At  the  anterior  extremity  of  its  nasal  surface  is  a  foramen, 
which  leads  into  a  canal  formed  conjointly  by  the  two  superior 
maxillary  bones, — the  naso-palatine  canal.  The  termination  of 
this  canal  is  situated  immediately  behind  the  incisor  teeth,  hence  it 
is  also  named  the  incisive  foramen.* 

Developement — By  six  centres  ;  one  for  the  body,  one  for  each 
of  the  three  processes,  nasal,  malar,  and  palate ;  and  two  for  the 
alveolar  process. 

Jlrticulations. — With  nine  bones,  viz.  with  two  of  the  cranium 
and  with  all  the  bones  of  the  face,  excepting  the  inferior  maxillary. 
These  are  the  frontal  and  ethmoid,  nasal,  lachrymal,  malar, 
inferior  turbinated,  palate,  vomer,  and  with  its  fellow  of  the  oppo- 
site side. 

Mtachmenl  of  Muscles. — To  nine;  orbicularis  palpebrarum,  obli- 
quus  inferior  oculi,  levator  labii  superioris  alseque  nasi,  levator  labii 
superioris  proprius,  levator  anguli  oris,  compressor  nasi,  depressor 
labii  superioris  alaeque  nasi,  buccinator,  masseter. 

Lachrymal  Boives — (os  unguis,  from  an  imagined  resemblance 
to  a  finger  nail).  The  lachrymal  (fig.  24)  is  a  thin  oval-shaped 
plate  of  bone,  situated  at  the  anterior  and  inner  angle  of  the  orbit. 
It  may  be  divided  into  an  external  and  internal  surface  and  borders. 
The  external  surface  is  smooth  and  marked  by  a  vertical  ridge, — 
the  lachrymal  crest, — into  two  portions,  one  of  which  is  flat  and 
enters  into  the  formation  of  the  orbit,  hence  may  be  called  the 
orbital  portion ;  the  other  is  concave,  and  lodges  the  lachrymal 
sac,  hence  the  lachrymal  portion.  The  internal  surface  is  rough 
and  completes  the  anterior  ethmoid  cells,  it  assists  in  forming  the 
wall  of  the  nasal  fossaj  and  nasal  duct. 

Developement. — By  a  single  centre. 

Articulations. — With/owr  bones;  two  of  the  cranium,  frontal  and 
ethmoid ;  and  two  of  the  face,  superior  maxillary,  and  inferior  tur- 
binated bone. 

Attachment  of  Muscles. — To  one  muscle,  the  tensor  tarsi,  and  to 
an  expansion  of  the  tendo  oculi,  the  former  arising  from  the  orbital 
surface,  the  other  being  attached  to  the  lachrymal  crest. 

Malar.  Bones — (mala,  the  cheek).  The  malar  (fig.  24)  is  the 
strong  quadrangular   bone  which   forms   the   prominence   of  the 

*  It  contains  the  ganglion  of  Clorjuet  from  the  fifth  pair. — G. 


PALATE  BONES.  69 

cheek.  It  is  divisible  into  an  external  and  internal  surface,  and 
four  processes,  the  frontal,  orbital,  maxillary,  and  zygomatic.  The 
external  surface  is  smooth  and  convex,  and  pierced  by  several 
small  openings  which  give  passage  to  filaments  of  the  temporo- 
malar  nerve  and  minute  arteries.  The  internal  surface  is  concave, 
partly  smooth  and  partly  rough  ;  smooth  where  it  forms  part  of 
the  temporal  fossa,  and  rough  where  it  articulates  with  the  superior 
maxillary  bone. 

The  frontal  process  ascends  perpendicularly  to  form  the  outer 
border  of  the  orbit,  and  articulates  with  the  external  angular  process 
of  the  frontal  bone.  The  orbital  process  is  a  thick  plate,  which  pro- 
jects inwards  from  the .  frontal  process,  and  unites  with  the  great 
ala  of  the  sphenoid  to  constitute  the  outer  wall  of  the  orbit.  It  is 
pierced  by  several  small  foramina  for  the  passage  of  temporo-malar 
filaments  of  the  superior  maxillary  nerve.  The  maxillary  process 
is  broad,  and  articulates  with  the  superior  maxillary  bone.  The 
zygomatic  process,  narrower  than  the  rest,  projects  backwards  to 
unite  with  the  zygoma  of  the  temporal  bone. 

Developement. — By  a  single  centre. 

Articulations. — With  four  bones  ;  three  of  the  cranium,  frontal, 
temporal,  and  sphenoid ;  and  one  of  the  face,  the  superior  maxillary 
bone. 

Attachment  of  Muscles. — To  six;  orbicularis  palpebrarum,  levator 
labii  superioris  proprius,  zygomaticus  minor,  and  major,  masseter, 
and  temporal. 

Palate  Bones. — The  palate  bones  are  situated  at  the  posterior 
part  of  the  nares,  where  they  enter  into  the 
formation  of  the  palate,  the  side  of  the  nose,  ^\-  21. 

and  the  posterior  part  of  the  floor  of  the  orbit ; 
hence  ihey  might  with  great  propriety  be  named 
the  palato-na so-orbital  bones.  Each  bone  re- 
sembles in  general  form  the  letter  L,  and  is 
divisible  into  a  horizontal  plate,  a  perpendi- 
cular plate,  and  a  pterygoid  process  or  tube- 
rosity. 

The  horizontal  plate  is  quadrilateral ;  and 
presents  two  surfaces,  one  superior,  which 
enters  into  the  formation  of  the  floor  of  the 
nares,  the  other  inferior,  forming  the  posterior 

Fig.  21.  A  posterior  view  of  the  palate  bone  in  its  natural  position  ;  it  is  slightly  turn- 
ed to  one  side  to  obtain  a  sight  of  the  internal  surface  of  the  perpendicular  plate  (2.)  1, 
The  horizontal  plate  of  the  bone  ;  its  upper  or  nasal  surface.  2.  The  perpendicular  plate ; 
its  internal  or  nasal  surface.  3.  10,  11.  The  pterygoid  process  or  tuberosity.  4.  The 
broad  internal  border  of  the  horizontal  plate  which  articulates  with  the  similar  border 
of  the  opposite  bone.  5.  The  pointed  process,  which  with  a  similar  process  of  the 
opposite  bone  forms  the  palate  spine.  6.  The  horizontal  ridge  which  gives  attach- 
ment to  the  inferior  turbinated  bone  ;  the  concavity  below  this  ridge  enters  into  the 
formation  of  the  inferor  meatus,  nnd  the  concavity  (2)  above  the  ridge  into  that  of  the 
middle  and  superior  meatus.  7.  The  splieno-palatine  foramen.  8.  The  orbital  portion. 
9.  The  pterygoid  apophysis.  10.  The  middle  facet  of  the  tuberosity,  which  enters  into 
the  formation  of  the  pterygoid  fossa.  The  facets  11  and  3  articulate  with  the  two 
pterygoid  plates, — 11  with  the  internal,  and  3  with  the  external. 


70 


PALATE  BONES. 


part  of  the  hard  palate.  The  swperior  surface  is  concave  and  rises 
towards  the  middle  line,  where  it  unites  with  its  fellow  of  the 
opposite  side  and  forms  a  crest,  which  articulates  with  the  vomer. 
The  inferior  surface  is  marked  by  a  slight  transverse  ridge,  to  which 
is  attached  the  tendinous  expansion  of  the  tensor  palati  muscle, 
and  near  to  the  external  border  are  two  openings,  the  posterior 
palatine  foramina,  which  transmit  the  posterior  palatine  neVves 
and  artery.  The  posterior  border  is  concave,  and  presents  at  its 
inner  extremity  a  sharp  point,  which  with  a  corresponding  point  in 
the  opposite  bone  constitutes  the  palate  spiiie  for  the  attachment  of 
the  azygos  uvulas  muscle. 

The  perpendicular  plate  is  also  quadrilateral ;  and  presents  two 
surfaces,  one  internal  or  nasal,  forming  a  part  of  the  wall  of  the  nares ; 
the  other  external,  bounding  the  spheno-maxillary  fossa  and  antrum. 
The  internal  surface  is  marked  near  its  middle  by  a  horizontal 
ridge,  to  which  is  united  the  inferior  turbinated  bone.  The  slightly 
concave  surface  below  this  ridge  enters  into  the  formation  of  the 
inferior  meatus  of  the  nose,  and  that  above  the  ridge  of  the  middle 
and  superior  meatus.  The  external  surface,  extremely  irregular,  is 
rough  on  each  side  for  articulation  with  the  neighbouring  bones, 
and  smooth  in  the  middle  to  constitute  the  inner  boundary  of  the 
spheno-maxillary  fossa.  This  smooth  surface  terminates  inferiorly 
in  a  deep  groove,  which  being  completed  by  the  tuberosity  of  the 
superior  maxillary  bone  forms  the  posterior  palatine  canal. 

Near  the  upper  part  of  the  perpendicular  plate  is  a  large  opening, 
the  spheno-palatijie  foramen,  which  transmits  the 
spheno-palatine  nerves  and  artery,  and  serves  to 
divide  the  upper  extremity  of  the  bone  into  two 
portions,  an  anterior  or  orbital,  and  a  posterior 
or  sphenoidal  portion.  The  orbital  portion  pre- 
sents five  surfaces  ;  three  articular,  and  two 
free;  the  three  articular  arelhe  anterior,  which 
looks  forward  and  articulates  with  the  superior 
maxillary  bone,  internal  with  the  ethmoid,  and 
posterior  with  the  sphenoid.  The  free  surfaces 
are  the  superior  or  orbital,  which  forms  the  pos- 
terior part  of  the  floor  of  the  orbit,  and  the  exter- 
nal, which  looks  into  the  spheno-maxillary  fossa. 
The  sphenoidal  portion/^  much  smaller  than 
the  orbital,  has  three  surfaces,  two  lateral  and  one  superior.  The 
external  lateral  surface  enters  into  the  formation  of  the  spheno- 

Fijr.  22.  The  perpendicular  plate  of  the  palate  bone  seen  upon  its  external  or  spheno- 
maxillary  surface.  1.  The  rough  surfixec  of  this  plate,  which  articulates  with  the  supe- 
rior maxillary  bone.  2.  The  posterior  palatine  canal,  completed  by  the  tuberosity  of 
the  superior  maxiliary  bone.  Tlie  rough  surface  to  the  left  of  the  canal  (2)  articulntes 
with  the  internal  pterygoid  plate.  3.  The  spheno-palatine  foramen.  4,  5,  6.  The 
orbital  portion  of  the  perpendicular  plnte.  4.  The  spheno-maxillary  facet  of  this  por- 
tion;  5.  its  orbital  facet;  6.  its  maxillary  facet,  to  articulate  with  the  s\ipcrior  maxil- 
lary bone.  7.  The  spiienoidal  portion  of  the  perpendicular  plate.  8.  The  pterygoid 
process  or  tuberosity  of  the  bone. 

*  Called  by  Horner,  the  pterygoid  apophysis. — G, 


INFERIOR  MAXILLARY  BONE.  71 

maxillary  fossa  ;  the  internal  lateral  forms  part  of  the  lateral  boun- 
dary of  the  nares ;  and  the  superior  surface  articulates  with  the 
under  part  of  the  body  of  the  sphenoid  bone. 

The  'pterygoid  process  or  tuberosity  of  the  palate  bone  is  the  thick 
and  rough  process  which  stands  backwards  from  the  angle  of  union 
of  the  horizontal  with  the  perpendicular  portion  of  the  bone.  It  is 
received  into  the  angular  fissure,  which  exists  between  the  two 
plates  of  the  pterygoid  process  at  their  inferior  extremity,  and  pre- 
sents three  surfaces  :  one  concave  and  smooth,  which  forms  part  of 
the  pterygoid  fossa ;  and  one  at  each  side  to  articulate  with  the 
pterygoid  plates.  The  anterior  face  of  this  process  articulates  with 
the  superior  maxillary  bone. 

Developement. — By  a  single  centre. 

Articulations. — With  six  bones;  two  of  the  cranium,  the  sphenoid 
and  ethmoid ;  and  four  of  the  face,  the  superior  maxillary,  inferior 
turbinated  bone,  vomer,  and  with  the  palate  bone  of  the  opposite 
side. 

Attachment  of  Muscles. — To  four ;  the  tensor  palati,  azygos  uvulee, 
internal  and  external  pterygoid. 

Inferior  Turbinated  Bone. — The  inferior  turbinated  or  spongy 
bone  is  a  thin  layer  of  loose  and  spongy  bone,  slightly  curled  upon 
itself,  and  projecting  inwards  from  the  inner  wall  of  the  nares.  It 
is  developed  from  a  single  centre,  and  gives  attachment  to  no 
muscles. 

Articulations. — W  it  h/owr  bones;  the  ethmoid,  superior  maxillary, 
lachrymal,  and  palate. 

Vomer. — The  vomer  is  a  thin  and  quadrilateral  plate,  forming  a 
part  of  the  septum  of  the  nares.  Superiorly,  it  is  broad  and  expanded, 
and  forms  a  sheath  for  the  rostrum  of  the  sphenoid ;  inferiorly,  it  is 
thin,  and  received  into  a  groove,  formed  by  the  articulation  between 
the  palate  processes  of  the  superior  maxillary  and  palate  bone  of 
opposite  sides.  The  posterior  border  is  free,  and  divides  the  poste- 
rior nares  ;  the  anterior  is  rough,  and  often  slit  into  two  layers,  to 
receive  the  sharp  edge  of  the  perpendicular  lamella  of  the  ethmoid 
bone,  and  of  the  cartilage  of  the  septum. 

The  vomer  frequently  presents  a  convexity  to  one  or  the  other 
side;  it  is  developed  by  a  single  centre,  and  has  no  muscles  attached 
to  it. 

Articulations. — With  six  bones  ;  the  sphenoid,  ethmoid,  two  supe- 
rior maxillary,  and  two  palate  bones,  and  with  the  cartilage  of  the 
septum. 

Inferior  Maxillary  Bone. — The  loioer  jaw  is  the  arch  of  bone 
which  contains  the  inferior  teeth  ;  it  is  divisible  into  a  horizontal 
portion  or  body,  and  a  perpendicular  portion,  the  ramus,  at  each 
side. 

Upon  the  external  surface  of  the  body  of  the  bone,  at  the  middle 
line,  and  extending  from  between  the  two  first  incisor  teeth  to  the 
chin,  is  a  slight  ridge,  called  the  symphysis.  Immediately  external 
to  this  ridge  is  a  depression  which  gives  origin  to  the  depressor  labii 


72 


INFERIOR  3IAXILLA.RY  BONE. 


inferioris  muscle ;  and  corresponding  with  the  root  of  the  lateral 
incisor  tooth,  another  depression,  the  incisive  fossa,  for  the  levator 
labii  inferioris.  Further  outwards  is  an  oblique  opening,  the 
anterior  mental  foramen,  for  the  exit  of  (he  inferior  dental  nerve 
and  artery,  and  below  this  foramen,  an  oblique  ridge  which  gives 
attachment  to  the  depressor  anguli  oris,  and  platysma  myoides. 
Near  the  posterior  part  of  this  surface  is  a  rough  impression  made^ 
by  the  masseter  muscle;  and  immediately  in  front  of  this  impres- 
sion, a  groove  may  occasionally  be  seen  for  the  facial  artery.  The 
projecting  tuberosity  at  the  posterior  extremity  of  the  lower  jaw,  at 
the  point  where  the  body  and  ramus  meet,  is  the  angle. 

Upon  the  internal  surface  of  the  body  of  the  bone  at  the  symphysis, 
are  two  small  pointed  tubercles ;  immediately  beneath  these,  two 
other  tubercles  less  marked  and  pointed,  beneath  them  a  ridge,  and 
beneath  the  ridge  a  rough  depression  of  some  size.  These  four 
points  give  attachment  from  above  downwards  to  the  genio-hyo- 
glossi,  genio-hyoidei,  part  of  the  mylo-hyoidei  and  to  the  digastric 
muscles.  Running  outwards  into  the  body  of  the  bone  from  the 
above  ridge,  is  a  prominent  line,  the  mylo-hyoidean  ridge,  which 
gives  attachment  to  the  mylo-hyoideus  muscle,  and  by  its  extremity 
to  the  pterygo-maxillary  ligament  and  superior  constrictor  muscle. 
Immediately  above  the  ridge,  and  by  the  side  of  the  symphysis,  is  a 
smooth  concave  surface,  which  corresponds  with  the  sublingual 
gland  ;  and  below  the  ridge,  and  more  externally,  a  deeper  fossa  for 
the  submaxillary  gland. 

The  ramus  is  a  strong  square-shaped  process,  differing  in  direc- 
tion at  various  periods  of  life ;  thus, 
in  the  fostus  and  infant,  it  is  almost 
parallel  with  the  body ;  in  youth  it 
is  oblique,  and  gradually  increases 
in  the  vertical  direction  until  man- 
hood ;  in  old  age,  after  the  loss  of 
the  teeth,  it  again  declines  and 
assumes  the  oblique  direction. 
Upon  its  external  surface  it  is 
rough,  for  the  attachment  of  the 
masseter  muscle ;  and  at  the  junc- 
tion of  its  posterior  border  with  the 
body  of  the  bone,  is  a  rough  tube- 
rosity, the  angle  of  the  lower  jaw, 
which  gives  attachment  by  its  inner  margin  to  the  stylo-maxillary 
ligament. 

The  upper  extremity  of  the  ramus  presents  two  processes,  sepa- 
rated by  a  concave  sweep,  the  sigmoid  notch.     The  anterior  is  the 


Fig.  23. 


Fig.  2:3.  The  lower  jaw.  1.  The  body.  2.  The  ramus.  .3.  Tlic  symphysis.  4.  The 
fossa  for  the  depressor  labii  inferioris  muscle.  5.  The  mental  foramen.  6.  The  external 
oblique  ridgo.  7.  The  groove  for  the  facial  artery.  8.  The  angle.  9.  TJie  extremity 
of  the  rnylo-hyoidcan  ridge.  10.  The  coronoid  ])roceRS.  II.  The  condyle.  12.  The 
sigmoid  notch.  13.  Tlie  inferior  dental  foramen.  14.  The  mylo-hyoidean  groove, 
1.5.  The  alveolar  process,  i.  The  middle  and  lateral  incisor  tooth  of  one  side.  c.  The 
canine  tooth,     b.  The  two  bicuspides.     in.  The  three  molarcs. 


TABLE  OF  DEVELOPEMENTS,  ARTICULATIONS,  ETC. 


73 


coronoid  process ;  it  is  sharp  and  pointed,  and  gives  attachment  by 
its  inner  surface  to  the  temporal  muscle.  The  anterior  border  of 
the  coronoid  process  is  grooved  at  its  lower  part  of  the  buccinator 
muscle.  The  posterior  process  is  the  condyle  of  the  lower  jaw, 
which  is  flattened  from  before  backwards,  and  smooth  upon  its 
upper  surface,  to  articulate  with  the  inter-articular  fibro-cartilage. 
The  constriction  around  the  base  of  the  condyle  is  its  neck,  into 
which  is  inserted  the  external  pterygoid  muscle.  The  sigmoid 
notch  is  crossed  by  the  masseteric  artery  and  nerve. 

The  internal  surface  of  the  ramus  is  marked  near  its  centre  by  a 
large  oblique  foramen,  the  inferior  dental,*  for  the  inferior  dental 
artery  and  nerve.  Around  this  opening  is  a  rough  margin,  to  which 
is  attached  the  internal  lateral  ligament,  and  passing  downwards 
from  the  opening  a  narrow  groove  which  lodges  the  mylo-hyoidean 
nerve.  To  the  rough  surface  above,  and  in  front  of  the  inferior 
dental  foramen,  is  attached  the  temporal  muscle,  and  to  that  below 
it  the  internal  pterygoid.  The  internal  surface  of  the  neck  of  the 
condyle  gives  attachment  to  the  external  pterygoid  muscle ;  and  the 
angle  to  the  stylo-maxillary  ligament. 

Developement. — By  two  centres ;  one  for  each  lateral  half,  the  two 
sides  meeting  at  the  symphysis,  where  they  become  united. 

Articulations. — With  the  glenoid  fossae  of  the  two  temporal  bones, 
through  the  medium  of  a  fibro-cartilage. 

Attachment  of  Muscles. — To  fourteen  pairs  ;  by  the  external  sur- 
face commencing  at  the  symphysis,  and  proceeding  outwards, — 
levator  labii  inferioris,  depressor  labii  inferioris,  depressor  anguli 
oris,  platysma  myoides,  buccinator  and  masseter;  by  the  internal 
surface  also  commencing  at  the  symphysis,  the  genio-hyo-glossus, 
genio-hyoideus,  mylo-hyoideus,  digastricus,  superior  constrictor, 
temporal,  external  pterygoid,  and  internal  pterygoid. 

Table  of  the  Points  of  Developement,  Articulations  and  Attachment  of 
Mii&cles,  of  the  Bones  of  the  Head. 


Occipital 

Parietal 

Frontal 

Temporal 

Sphenoid 
^Ethmoid 
-l-Nasal     .       .       . 

Superior  maxillary 

Lachrymal   . 

Malar     .       .       . 

Palate     . 

Inferior  turbinated 

Vomer   . 

Lower  jaw    . 


Developemen 

.  Articulatior 

4 

6       . 

1 

5       . 

2 

12       . 

5       . 

5        . 

12       . 

12       . 

3       . 

13       . 

1       . 

4       . 

6       . 

9 

4 

4       . 

« 

6       . 
4       . 

6       . 

2 

2       . 

Attachment  of 
muscles. 

13  pairs. 

1  muscle. 
4  pairs. 

14  muscles. 
12  pairs. 

none. 

none. 
9  muscles. 
1  ib. 
6  ib. 
4ib. 

none. 

none.   . 
14  pairs. 


*  Called  also  posterior  mental  foramen, — G. 

7 


SUTURES — OSSA  TRIQUETRA. 


SUTURES. 


The  bones  of  the  cranium  and  face  are  connected  wiih  each 
other  by  means  of  sutures  (sutura,  a  seam),  of  which  there  are  four 
principal  varieties, — serrated,  squamous,  harmonia,  and  schindylesis. 

The  serrated  suture  is  formed  by  the  union  of  two  borders  pos- 
sessing serrated  edges,  as  in  the  coronal,  sagittal,  and  lambdoidal 
sutures.  In  these  sutures  the  serrations  are  formed  almost  wholly 
by  the  external  table,  the  edges  of  the  internal  table  lying  nearly  in 
apposition. 

The  squamous  suture  (squama,  a  scale)  is  formed  by  the  over- 
lapping of  the  bevelled  edges  of  two  continuous  bones,  as  in  the 
articulation  between  the  temporal  and  lower  border  of  the  parietal. 
In  this  suture  the  approximated  surfaces  are  roughened,  so  as  to 
adhere  mechanically  to  each  other. 

The  harmonia  suture  («gw,  to  adapt)  is  the  simple  apposition  of 
contiguous  surfaces,  the  surfaces  being  more  or  less  rough  and  I'e- 
tentive.  This  suture  is  seen  in  the  connexion  between  the  superior 
maxillary  bones,  or  of  the  palate  processes  of  the  palate  bones  with 
each  other. 

The  schindylesis  suture  (ff'xiviJuXiiff'tff,  a  fissure)  is  the  reception  of 
one  bone  into  a  sheath  or  fissure  of  another,  as  occurs  in  the  articu- 
lation of  the  sphenoid  with  the  vomer,  or  of  the  latter  with  the  per- 
pendicular lamella  of  the  ethmoid,  and  with  the  palate  processes  of 
the  superior  maxillary  and  palate  bones. 

The  serrated  suture  is  formed  by  the  interlocking  of  the  radia- 
ting fibres  along  the  edges  of  the  flat  bones  of  the  cranium  during 
growth.  When  this  process  is  retarded  in  the  infant  by  over-dis- 
tention  of  the  head,  as  in  hydrocephalus,  and  sometimes  without 
any  such  apparent  cause,  distinct  ossific  centres  are  developed  in 
the  interval  between  the  edges;  and,  being  surrounded  by  the 
suture,  form  independent  pieces,  which  are  called  ossa  triquetra,  or 
ossa  Wormiana.  In  the  lambdoidal  suture  there  is  generally  one  or 
more  of  these  bones;  and,  in  a  beautiful  adult  hydrocephalic 
skeleton  in  the  possession  of  Mr.  Liston,  there  are  upwards  of  one 
hundred. 

The  coronal  suture  (fig.  24)  extends  transversely  across  the 
vertex  of  the  skull,  from  the  upper  part  of  the  greater  wing  of  the 
sphenoid  to  the  same  point  on  the  opposite  side;  it  connects  the 
frontal  whh  the  parietal  bones.  In  the  formation  of  this  suture  the 
edges  of  the  articulating  bones  are  bevelled,  so  that  the  parietal 
rest  upon  the  frontal  at  each  side,  and  in  the  middle  the  frontal  rests 
upon  the  parietal  bones,  so  as  to  afford  each  other  mutual  support 
in  the  consolidation  of  the  skull. 

The  sagittal  suture  (fig.  24)  eoctends  longitudinally  backwards 
along  the  vertex  of  the  skull,  from  the  middle  of  the  coronal  to  the 
apex  of  the  lambdoidal  suture.  It  is  very  much  serrated,  and  serves 
to  unite  the  two  parietal  bones.     Sometimes  this  suture  is  continued 


SUPERIOR  REGIONS  OF  THE  SKULL.  75 

through  the  middle  of  the  frontal  bone  to  the  root  of  the  nose,  under 
the  name  of  the  frontal  suture. 

The  lamhdoidal  suture  is  named  from  some  resemblance  to  the 
Greek  letter  A,  consisting  of  two  branches,  which  diverge  at  an 
acute  angle  from  the  extremity  of  the  sagittal  suture.  This  suture 
connects  the  occipital  with  the  parietal  bones.  At  the  posterior  and 
inferior  angle  of  the  parietal  bones,  the  lambdoidal  suture  is  con- 
tinued onwards  in  a  curved  direction  into  the  base  of  the  skull,  and 
serves  to  unite  the  occipital  bone  with  the  mastoid  portion  of  the 
temporal,  under  the  name  of  the  addilnmentam  sutures  lambdoidalis. 
It  is  in  the  lambdoidal  suture  that  the  ossa  triquetra  occur  most 
frequently. 

The  squamous  suture  (fig.  24)  unites  the  squamous  portion  of  the 
temporal  bone  with  the  greater  ala  of  the  sphenoid  and  with  the 
parietal,  overlapping  the  lower  border  of  the  latter.  The  portion 
of  the  suture  which  is  continued  backwards  from  the  squamous 
portion  of  the  bone  to  the  lambdoidal  suture,  and  connects  the  mas- 
toid portion  with  the  posterior  inferior  angle  of  the  parietal  is  the 
addiiamenium  sutures  squamosa;. 

Across  the  upper  part  of  the  face  is  an  irregular  suture,  the  trans- 
verse, which  connects  the  frontal  bone  with  the  nasal,  superior  max- 
illary, lachrymal,  ethmoid,  sphenoid,  and  malar  bones.  The  other 
sutures  are  too  unimportant  to  deserve  particular  names  or  descrip- 
tion. 

REGIONS    OF    THE     SKULL. 

The  skull  considered  as  a  whole,  is  divisible  into  four  regions, — 
a  superior  region,  or  vertex  ;  a  lateral  region ;  an  inferior  region, 
or  base  ;  and  an  anterior  region,  the  face. 

The  superior  region,  or  vertex  of  the  skull,  is  bounded  anteriorly 
by  the  frontal  eminences ;  on  each  side  by  the  temporal  ridge  and 
parietal  eminences ;  and  behind  by  the  superior  curved  line  of 
the  occipital  bone  and  occipital  protuberance.  It  is  crossed  trans- 
versely by  the  coronal  suture,  and  marked  from  before  backwards 
by  the  sagittal,  which  terminates  posteriorly  in  the  lambdoidal  suture. 
Near  the  posterior  extremity  of  the  region,  and  on  each  side  of  the 
sagittal  suture,  is  the  parietal  foramen.  Upon  the  inner,  ox  cerebral 
surface  of  this  region,  is  a  shallow  groove,  extending  along  the 
middle  line  from  before  backwards,  for  the  superior  longitudinal 
sinus  ;  on  either  side  of  this  groove  are  several  small  fossae  for  the 
Pacchionian  bodies,  and  still  further  outwards  numerous  ramified 
markings  for  lodginor  the  branches  of  the  arteria  meninfirea  media. 

The  lateral  region  of  the  skull  is  divisible  into  three  portions; 
temporal,  mastoid,  and  zygomatic. 

The  temporal  portion,  or  temporal,  fossa,  is  bounded  above  and 
behind  by  the  temporal  ridge,  in  front  by  the  external  angular  pro- 
cess of  the  frontal  bone  and  by  the  malar  bone,  and  below  by  the 
zygoma.     It  is  formed  by  part  of  the  frontal,  great  wing  of  the 


76 


BASE   OF  THE  SKULL. 


sphenoid,  parietal,  squamous  portion  of  the  temporal,  and  malar 
bone,  and  lodges  the  temporal  muscle. 


Fi<r.  24. 


Fig.  25. 


The  mastoid  portion  is  rough,  for  the  attachment  of  muscles. 
Upon  its  posterior  part  is  the  mastoid  foramen,  and  below,  the  mas- 
toid process.  In  front  of  the  mastoid  process  is  the  external  audi- 
tory foramen,  surrounded   by  the  external  auditory  process ;  and 


Fig.  24.  A  front  view  of  the  skull.  1.  The  frontal  portion  of  the  frontal  bone.  The  2 
immediately  over  the  root  of  the  nose,  refers  to  the  nasal  tuberosity  ;  the  3  over  the  orbit, 
to  the  supra-orbital  ridge.  4.  The  optic  foramen.  5.  The  sphenoidal  fissure.  6.  The 
spheno-maxillary  fissure.  7.  The  lachrymal  fossa  in  the  lachrymal  bone,  the  com- 
iTiencement  of  the  nasal  duct.  The  figures  4,  5,  6,  7,  are  within  the  orbit.  8.  The 
opening  of  the  anterior  nares  divided  into  two  parts  by  the  vomer  ;  the  number  is 
placed  upon  the  latter.  9.  The  infra-orbital  foramen.  10.  The  malar  bone.  11.  The 
symphysis  of  the  lower  jaw.  12.  The  mental  foramen.  13.  The  ramus  of  the  lower 
jaw.  14.  The  parietal  bone.  15.  The  coronal  suture.  16.  The  temporal  bone.  17. 
The  squamous  suture.  18.  The  upper  part  of  the  great  ala  of  the  sphenoid  bone.  19. 
The  commencement  of  the  temporal  ridge.  20.  The  zygoma  of  the  temporal  bone, 
assisting  to  form  the  zygomatic  arch.     21.  The  mastoid  process. 

Fig.  25.  The  cerebral  surface  of  the  base  of  the  skull.  1.  One  side  of  the  anterior 
fossa;  the  number  is  placed  on  the  roof  of  the  orbit,  formed  by  the  orbital  plate  of  the 
frontal  bone.  2.  The  lesser  wing  of  the  sphenoid.  3.  The  crista  galli.  4.  The  fora- 
men ca3cum.  5.  The  cribriform  lamella  of  the  ethmoid.  6.  The  processus  olivaris. 
7.  The  foramen  opticum.  8.  The  anterior  clinoid  process.  9.  The  carotid  groove  upon 
the  side  of  the  sella  Turcica,  for  the  internal  carotid  artery  and  cavernous  sinus.  10, 
11,  12.  The  middle  fossa  of  the  base  of  the  skull.  10.  Marks  the  gieat  ala  of  the  sphe- 
noid. 11.  The  squamous  portion  of  the  temporal  bone.  12.  The  petrous  portion  of 
the  temporal.  13.  The  sella  Turcica.  14.  The  basilar  portion  of  the  sphenoid  bone 
surmounted  by  the  posterior  clinoid  processes.  15.  The  foramen  rotundum.  16.  The 
foramen  ovale.  17.  The  foramen  spiiiosum  ;  the  small  irregular  opening  between  17. 
and  12  is  the  hiatus  Fallo[)ii.  18.  The  posterior  fossa  of  the  base  of  the  skull.  19. 
The  groove  for  the  lateral  sinus.  20.  The  ridge  upon  the  occipital  bone,  which 
gives  attachment  to  the  falx  cercbelli.  21.  The  foramen  magnum.  22.  The  meatus 
auditorius  inlernus.    23.  The  jugular  foramen. 


BASE  OF  THE  SKULL.  77 

in  front  of  this  foramen  the  glenoid  cavity,  bounded  above  by  the 
middle  root  of  the  zygoma,  and  in  front  by  its  tubercle. 

The  zygomatic  portion,  or  fossa,  is  the  irregular  cavity  below  the 
zygoma,  bounded  in  front  by  the  superior  maxillary  bone,  internally 
by  the  external  pterygoid  plate,  above  by  part  of  the  great  wing  of 
the  sphenoid  and  squamous  portion  of  the  temporal  bone,  and  by  the 
temporal  fossa,  and  externally  by  the  zygomatic  arch  and  ramus  of 
the  lower  jaw.  It  contains  the  external  pterygoid,  with  part  of  the 
temporal  and  internal  pterygoid  muscle,  and  the  internal  maxillary 
artery  and  inferior  maxillary  nerve,  wdth  their  branches.  At  the 
bottom  of  the  zygomatic  fossa  are  two  fissures,  the  spheno-maxillary 
and  the  pterygo-maxillary. 

The  spheno-maxillary  fisswe  is  horizontal  in  direction,  opens  into 
the  orbit  and  is  situated  between  the  great  ala  of  the  sphenoid  and 
the  superior  maxillary  bone. 

The  pterygo-maxiUary  fissure  is  vertical,  and  descends  at  right 
angles  from  the  extremity  of  the  preceding.  It  is  situated  between 
the  pterygoid  process  and  tuberosity  of  the  superior  maxillary  bone, 
and  transmits  the  internal  maxillary  artery.  At  the  angle  of  junc- 
tion of  these  two  fissures  is  a  small  cavity,  the  spheno-maxillary 
fossa,  bounded  by  the  sphenoid,  palate,  and  superior  maxillary  bones, 
in  which  are  seen  the  openings  of  five  foramina, — the  foramen  ro- 
tundum,  spheno-palatine,  pterygo-palatine,  posterior  palatine,  and 
Vidian.  It  lodges  Meckel's  ganglion  and  the  termination  of  the  in- 
ternal maxillary  artery. 

The  base  of  the  skull  presents  an  internal  or  cerebral,  and  an  ex- 
ternal or  basilar  surface. 

The  cerebral  surface  is  divisible  into  three  parts,  which  are  named 
the  anterior,  middle,  and  posterior  fossa  of  the  base  of  the  cranium. 
The  anterior  fossa  is  somewhat  convex  on  each  side,  where  it  cor- 
responds with  the  roofs  of  the  orbits;  and  concave  in  the  middle, 
in  the  situation  of  the  ethmoid  bone,  and  the  anterior  part  of  the 
body  and  lesser  wings  of  the  sphenoid,  which  constitute  its  posterior 
boundary.  It  supports  the  anterior  lobes  of  the  cerebrum.  In  the 
middle  line  of  this  fossa,  at  its  anterior  part,  is  the  crista  galli,  im- 
mediately in  front  of  this  process,  the  foramen  ccEcum,  and  on  each 
side  the  cribriform  plate,  with  its  fora7nina,  for  the  transmission  of 
the  filaments  of  the  olfactory  and  nasal  branch  of  the  ophthalmic 
nerve.  Farther  back  in  the  middle  line  is  the  processus  olivaris,  and 
on  the  sides  of  this  process  the  optic  foramina,  anterior  clinoid  pro- 
cesses, and  vertical  grooves  for  the  internal  carotid  arteries. 

The  middle  fossa  of  the  base,  deeper  than  the  preceding,  is 
bounded  in  front  by  the  lesser  wing  of  the  sphenoid  ;  behind,  by  the 
petrous  portion  of  the  temporal  bone  ;  and  is  divided  into  two  lateral 
parts  by  the  sella  Turcica.  It  is  formed  by  the  posterior  part  of 
the  body,  great  ala,  and  spinous  process  of  the  sphenoid,  and  by  the 
petrous  and  squamous  portion  of  the  temporal  bones.  In  the  centre 
of  this  fossa  is  the  sella  Turcica,  which  lodges  the  pituitary  gland, 
bounded  in  front  and  behind  by  the  anterior  and  posterior  clinoid 

'  7* 


78  BASE  OF  THE  SKULL. 

processes.  On  each  side  of  the  sella  Turcica  is  the  carotid  groove 
for  the  internal  carotid  artery,  the  carotid  plexus  of  nerves,  the 
cavernous  sinus,  and  the  orbital  nerves,  and  a  little  father  outwards 
the  following  foramina  from  before  backwards,  sphenoidal  fissure 
(foramen  lacerum  anterius)  for  the  transmission  of  the  third,  fourth, 
three  branches  of  the  ophthalmic  division  of  the  fifth,  and  the  sixth 
nerve,  and  ophthalmic  vein ;  foramen  rotundum,  for  the  superior  max- 
illary nerve  ;  foramen  ovale,  for  the  inferior  maxillary  nerve,  ai'teria 
meningea  parva,  and  nervus  petrosus  superficialis  minor  ; — foramen 
spinosum,  for  the  arteria  meningea  magna  ;  foramen  lacerum  basis 
cranii,  which  gives  passage  to  the  internal  carotid  artery,  carotid 
plexus,  and  petrosal  branch  of  the  A'^idian  nerve.  On  the  anterior 
surface  of  the  petrous  portion  of  the  temporal  bone  is  a  groove, 
leading  to  a  fissured  opening,  the  hiatus  Fallopii,  for  the  petrosal 
branch  of  the  Vidian  nerve  ;  and  immediately  beneath  this  a  smaller 
foramen,  for  the  nervus  petrosus  superficialis  minor.  Towards 
the  apex  of  this  portion  of  bone  is  the  notch  for  the  fifth  nerve,  and 
below  it  a  slight  depression  for  the  Casserian  ganglion.  Farther 
outwards  is  the  eminence  which  marks  the  position  of  the  perpen- 
dicular semicircular  canal.  Proceeding  from  the  foramen  spinosum 
are  two  grooves  which  mark  the  course  of  the  trunks  of  the  arteria 
meningea  media.  The  whole  fossa  lodges  the  middle  lobes  of  the 
cerebrum. 

The  posterior  fossa,  larger  than  the  other  two,  is  formed  by  the 
occipital  bone,  by  the  petrous  and  mastoid  portion  of  the  temporals, 
and  by  a  small  part  of  the  sphenoid  and  parietals.  It  is  bounded  in 
front  by  the  upper  border  of  the  petrous  portion,  and  by  the  poste- 
rior clinoid  processes,  and  along  its  posterior  circumference  by  the 
groove  for  the  lateral  sinuses,  and  gives  support  to  the  pons  Varolii, 
medulla  oblongata,  and  cerebellum.  In  the  centre  of  this  fossa  is 
the  foramen  magnum  bounded  on  each  side  by  a  rough  tubercle, 
which  gives  attachment  to  the  odontoid  ligament,  and  by  the  anterior 
condyloid  foramen.  In  fi'ont  of  the  foramen  magnum  is  the  con- 
cave surface  which  supports  the  medulla  oblongata  and  pons  Va- 
rolii, and  on  each  side  the  following  foramina  from  before  back- 
wards. The  internal  auditory  foramen,  for  the  auditory  and  facial 
nerve  and  auditory  artery  ;  behind,  and  external  to  this  is  a  small 
foramen  leading  into  the  aquceductus  vestibuU ;  and  below  it,  partly 
concealed  by  the  edge  of  the  petrous  bone,  the  aquccductus  cochlecc; 
next,  a  long  fissure,  the  foramen  lacerum  poster ius,  or  jugular  fora- 
men, giving  passage  to  the  commencement  of  the  internal  jugular 
vein  and  the  eighth  pair  of  nerves.  Converging  towards  this  fora- 
men from  behind  is  the  deep  groove  for  the  lateral  sinus,  and  from 
the  front  the  gnjove  for  the  inferior  petrosal  sinus. 

Behind  the  foramen  magnum  is  a  longitudinal  ridge,  which  gives 
attachment  to  the  falx  cerebelli,  and  divides  the  two  inferior  fossa3  of 
the  occipital  bone  ;  and  above  the  ridge  is  the  elevation  correspond- 
ing with  the  tubercle  of  the  occipital  bone  and  the  transverse  groove 
lodging  the  lateral  sinus. 


EASE  OF  THE  SKULL. 


79 


Fig.  26. 


The  external  surface  of  the  base  of  the  skull  is  extremely  irregu- 
lar. From  before  backwards  it  is  formed  by  the  palate  processes 
of  the  superior  maxillary  and  pa- 
late bones  ;  the  vomer  ;  the  ptery- 
goid, spinous  processes,  and  part 
of  the  body  of  the  sphenoid  ;  under 
surface  of  the  squamous  portion, 
and  mastoid  portion  of  the  tem- 
porals ;  and  by  the  occipital  bone. 
The  palate  processes  of  the  supe- 
rior maxillary  and  palate  bones 
constitute  the  hard  palate,  which 
is  raised  above  the  level  of  the 
rest  of  the  base,  and  is  surrounded 
by  the  alveolar  processes  contain- 
ing the  teeth  of  the  upper  jaw.  At 
the  anterior  extremity  of  the  hard 
palate,  and  directly  behind  the 
front  incisor  teeth,  is  the  incisive 
foramen,  the  termination  of  the  naso- 
palatine canal,  which  contains  the 
naso-palatine  ganglion,  and  trans- 
mits the  anterior  palatine  nerves.  At 
the  posterior  angles  of  the  palate  are  the  postenor  palatine  foramina, 
for  the  posterior  palatine  nerves  and  arteries.  Passing  inwards  from 
these  foramina  are  the  transnerse  ridges  to  which  are  attached  the 
expansions  of  the  tensor  palati  muscles,  and  at  the  middle  line  of  the 
posterior  border  the  palate  spine  which  gives  origin  to  the  azygos 
uvulse.  The  hard  palate  is  marked  by  a  crucial  suture,  which  distin- 
guishes the  four  processes  of  which  it  is  composed.  Behind,  and  above 
the  hard  palate,  are  the  posterior  nares,  separated  by  the  vomer,  and 
bounded  on  each  side  by  the  pterygoid  processes.  At  the  base  of  the 
vomer,  and  partly  formed  by  its  expansion,  are  the  ptery go-palatine 
canals.  The  internal  pterygoid  plate  is  long  and  narrow,  terminated 
at  its  apex  by  the  hamular  process,  and  at  its  base  by  the  scaphoid 
fossa.  The  external  plate  is  broad,  and  the  space  between  the  two 
is  the  pterygoid  fossa,  which  contains  part  of  the  internal  pterygoid 
muscle  and  the  tensor  palati.     Externally  to  the  external  pterygoid 


Fig-.  26.  The  external  or  basilar  surface  of  the  base  of  the  skull.  1,1,  the  hard  palate. 
The  figures  are  placed  upon  the  palate  processes  of  the  superior  maxillary  bones.  2, 
The  incisive,  or  anterior  palatine  foramen.  3.  The  palate  process  of  the  palate  bone. 
The  large  opening  near  the  figure  is  the  posterior  palatine  foramen.  4.  The  palate 
spine  ;  the  curved  line  upon  which  the  number  rests,  is  the  transverse  ridge.  5.  The 
vomer,  dividing  the  openings  of  the  posterior  nares.  6.  The  internal  pterygoid  plate. 
7.  The  scaphoid  fossa.  8.  The  external  pterygoid  plate.  The  interval  between  6  and  8, 
(left  side  of  the  figure,)  is  the  pterygoid  fossa.  9.  The  zygomatic  fossa.  10.  The 
basilar  process  of  the  occipital  bnne.  11.  The  foramen  magnum.  12.  The  foramen 
ovale.  13.  The  foramen  spinosum.  14.  The  glenoid  fossa.  1.5.  The  meatus  audi- 
torius  externus.  16.  The  foramen  l.icerum  basis  cranii.  17.  The  carotid  foramen  of 
the  left  side.  18.  The  foramen  lacerum  posterioris,  or  jugular  foramen.  19.  The 
styloid  process.  20.  The  stylo-mastoid  foramen.  21.  The  mastoid  process.  22.  One 
of  the  condyles  of  the  occipital  bone.     23.  The  posterior  condyloid  foramen. 


80  BASE  OP  THE  SKULL. 

is  the  Z3'gomatic  fossa.  Behind  the  nasal  fossse,  in  the  middle  line, 
is  the  under  surface  of  the  body  of  the  sphenoid,  and  the  basilar 
process  of  the  occipital  bone,  and  slill  further  back,  the  foramen 
magnum.  At  the  base  of  the  external  pterygoid  plate,  on  each 
side,  is  the  foramen  ovale,  and  beliind  this  the  foramen  spinosum, 
with  the  prominent  spine  which  gives  attachment  to  the  internal 
lateral  ligament  of  the  lower  jaw  and  the  laxator  tympani  muscle. 
Running  outwards  from  the  apex  of  the  spinous  process  of  the 
sphenoid  bone,  is  the  fissura  Glaseri,  which  crosses  the  glenoid 
fossa  transversely,  and  divides  it  into  an  anterior  smooth  surface, 
bounded  by  the  eminentia  arlicularis,  for  the  condyle  of  the  lower 
jaw,  and  a  posterior  rough  surface  for  a  part  of  the  parotid  gland. 
Behind  the  foramen  ovale  and  spinosum,  is  the  irregular  fissure 
between  the  spinous  process  of  the  sphenoid  bone  and  the  petrous 
portion  of  the  temporal,  the  foramen  lacerum  basis  cranii,  which 
lodges  the  internal  carotid  artery  and  Eustachian  tube,  and  in 
which  the  carotid  branch  of  the  Vidian  nerve  joins  the  carotid 
plexus.  Following  the  direction  of  this  fissure  outwards  is  the 
foramen  for  the  Eustachian  tube,  and  that  for  the  tensor  tympani 
muscle,  separated  from  each  other  by  the  processus  cochleariformis. 
Behind  the  fissure  is  the  pointed  process  of  the  petrous  bone  which 
gives  origin  to  the  levator  palati  muscle,  and,  externally  to  this  pro- 
cess, the  carotid  foramen  for  the  transmission  of  the  internal  carotid 
artery  and  the  ascending  branch  of  the  superior  cervical  ganglion 
of  the  sympathetic  ;  and  behind  the  carotid  foramen,  the  foramen 
lacerum  posterius  and  jugular  fossa.  Externally,  and  somewhat  in 
front  of  the  latter,  is  the  styloid  process,  and  at  its  base  the  vaginal 
process.  Behind  and  at  the  root  of  the  styloid  process  is  the  stylo- 
mastoid foramen,  for  the  facial  nerve  and  stylo-mastoid  artery,  and 
further  outwards  the  mastoid  process.  Upon  the  inner  side  of  the 
root  of  the  mastoid  process  is  the  digastric  fossa  ;  and  a  little  far- 
ther internally,  the  occipital  groove.  On  either  side  of  the  fora- 
men magnum,  and  near  to  its  anterior  circumference,  are  the  con- 
dyles of  the  occipital  bone.  In  front  of  each  condyle,  and  piercing 
its  base,  is  the  anterior  condyloid  foramen,  and  directly  behind  the 
condyle  the  irregular  fossa  in  which  the  posterior  condyloid  foramen 
is  situated.  Behind  the  foramen  magnum  are  the  two  curved  lines 
of  the  occipital  bone,  the  spine,  and  protuberance,  with  the  rough 
surfaces  for  the  attachment  of  muscles. 

The  Face  is  somewhat  oval  in  contour,  irregular  in  surface,  and 
excavated  for  the  reception  of  two  principal  organs  of  sense, — the 
eye  and  the  nose.  It  is  formed  by  part  of  the  frontal  bone  and  by 
the  bones  of  the  face.  Superiorly  it  is  bounded  by  the  frontal 
eminences;  beneath  these  are  the  superciliary  ridges,  converging 
towards  the  nasal  tuberosity  ;  beneath  the  superciliary  ridges  are 
the  supra-orbital  ridges,  terminating  externally  in  the  external 
border  of  the  orbit,  and  internally  in  the  internal  border,  and  pre- 
senting towards  their  inner  third  the  supra-orbital  notch,  for  the 
supra-orbital  nerve  and  artery.  Beneath  the  supra-orbital  ridges 
are  the  openings  of  the  orbits.     Between  the  orbits  is  the  bridge  of 


THE  FACE.  81 

the  nose,  overarching  the  anterior  nares ;  and  on  each  side  of  this 
opening  the  canine  fossa  of  the  superior  maxillary  bone  and  the 
infra-orbital  foramen,  and  still  farther  outwards  the  prominence  of 
the  malar  bone ;  at  the  lower  margin  of  the  anterior  nares  is  the 
nasal  spine,  and  beneath  this  the  superior  alveolar  arch  containing 
the  teeth  of  the  upper  jaw.  Forming  the  lower  boundary  of  the 
face  is  the  lower  jaw,  containing  in  its  alveolar  process  the  lower 
teeth,  and  projecting  inferiorly  to  form  the  chin  ;  on  either  side  of 
the  chin  is  the  mental  foramen.  If  a  perpendicular  line  be  drawn 
from  the  inner  third  of  the  supra-orbital  ridge  to  the  inner  third  of 
the  body  of  the  lower  jaw,  it  will  be  found  to  intersect  three  open- 
ings ; — the  supra-orbital,  infra-orbital,  and  mental,  each  giving 
passage  to  one  of  the  facial  branches  of  the  fifth  nerve. 

ORBITS. 

The  orbits  are  two  quadrilateral  hollow  cones,  situated  in  the 
upper  part  of  the  face,  and  intended  for  the  reception  of  the  eye- 
balls, with  their  muscles,  vessels  and  nerves,  and  the  lachrymal 
glands.  The  central  axis  of  each  orbit  is  directed  outwards,  so 
that  the  axes  of  the  two  continued  into  the  skull  through  the  optic 
foramina,  would  intersect  over  the  middle  of  the  sella  Turcica.* 
The  superior  boundary  of  the  orbit  is  formed  by  the  orbital  plate  of 
the  frontal  bone,  and  by  part  of  the  lesser  wing  of  the  sphenoid ; 
the  inferior,  by  part  of  the  malar  bone  and  by  the  orbital  processes 
of  the  superior  maxillary  and  palate  bone;  the  internal  by  the 
lachrymal  bone,  the  os  planum  of  the  ethmoid  and  part  of  the 
body  of  the  sphenoid  ;  and  the  external,  by  the  orbital  process  of 
the  malar  bone  and  the  great  ala  of  the  sphenoid ;  these  may  be 
expressed  more  clearly  in  a  tabular  form  : 


Frontal. 
Sphenoid  (lesser  wing). 


Malar. 
Sphenoid  (greater  wing). 


Riffht  Orbit. 


Lachrymal. 

Ethmoid  (os  planum). 

Sphenoid  (body). 


Malar. 

Superior  maxillary. 

Palate. 

There  are  nine  openings  communicating  with  the  orbit: — the 
optic,  for  the  admission  of  the  optic  nerve  and  ophthalmic  artery  ; 
the  sphenoidal  fissure,  for  the  transmission  of  the  third,  fourth,  the 
three  branches  of  the  ophthalmic  division  of  the  fifth,  and  the  sixth 
nerve,  and  the  ophthalmic  vein  ;  the  spheno-7naxiUary  fissure,  for  the 
passage  of  the  superior  maxillary  nerve  and  artery  to  the  opening 
of  entrance  of  the  infra-orbital  canal;  temporo-malar  foramina — 
two  or  three  small  openings  in  the  orbital  process  of  the  malar 

*  The  axes  of  the  orbits  form  an  angle  of  90°  with  each  other. — G. 


82 


NASAL  FOSS^. 


bone,  for  the  passage  of  filaments  of  the  orbital  branch  of  the  supe- 
rior maxillary  nerve;  anterior  and  posterior  ethmoidal  foramina  in 
the  suture  between  the  os  planum  and  frontal  bone,  the  former 
transmitting  the  nasal  nerve  and  anterior  ethmoidal  artery  and 
the  latter  the  posterior  ethmoidal  artery  and  vein ;  the  opening  of 
the  nasal  duct;  and  the  supra-orbital  notch  or  foramen,  for  the 
supra-orbital  nerve  and  artery. 


NASAL     FOSSiE. 


The  nasal  fossse  are  tvv^o  irregular  cavities,  situated  in  tHe  middle 
of  the  face,  and  extending  from  before  backwards.  They  are 
bounded  above  by  the  nasal  bones,  ethmoid,  and  sphenoid;  beloio 
by  the  palate  processes  of  the  superior  maxillary  and  palate  bones; 
externally  by  the  superior  maxillary,  lachrymal,  inferior  turbinated, 
ethmoid,  palate,  and  internal  pterygoid  plate  of  the  sphenoid;  and 
the  two  fossEe  are  separated  by  the  vomer  and  the  perpendicular 
lamella  of  the  ethmoid.  These  may  be  more  clearly  expressed  in 
a  tabular  form : 

Nasal  bones. 
Ethmoid. 
Sphenoid. 


<o 

2 

>. 

"E, 

>>        T3 

L. 

>3           <D 

ta 

d 

a      -y 

"O 

—  _^   cd 

•-<     rd    C 

Nasal  fossa. 

'o 

a 

J3 

Nasal  fossa. 

max 
rymi 
turbi 
late. 

-C2     Ut 

^ 

t.  -C          oj 

o  o 

T) 

^^    u 

C 

<"  '-'    S 

a. 

cd 

O-        t£ 

3 

t4 

2       a 

02 

s 

m     1-1 

c^cL, 


Palate  processes  of  superior  maxillary. 
Palate  processes  of  palate  bone. 

Each  nasal  fossa  is  divided  into  three  irregular  longitudinal  pas- 
sages, or  meatuses  by  three  processes  of  bone,  which  project  from 
its  outer  wall, — the  superior,  middle,  and  inferior  turbinated  bones; 
the  superior  and  middle  turbinated  bones  being  processes  of  the 
ethmoid,  and  the  inferior  a  distinct  bone  of  the  face.  The  superior 
meatus  occupies  the  superior  and  posterior  part  of  each  fossa  ;  it  is 
situated  between  the  superior  and  middle  turbinated  bones,  and  has 
opening  into  it  three  foramina,  viz.  the  opening  of  the  posterior 
ethmoid  cells,  the  opening  of  the  sphenoid  cells,  and  the  spheno- 
palatine foramen.  The  middle  meatus  is  the  space  between  the 
middle  and  inferior  turbinated  bones;  it  also  presents  three  foramina, 
— the  opening  of  the  frontal  sinuses,  of  the  anterior  ethmoid  cells, 
and  of  the  antrum.  The  largest  of  the  three  passages  is  the  in- 
ferior meatus,  which  is  the  space  between  the  inferior  turbinated 
bone  and  the  floor  of  the  fossa;  in  it  there  are  two  foramina, — the 


TEETH DIVISIONS. 


83 


termination  of  the  nasal  duct,  and  the  opening  of  the  naso-palatine 
canal.  The  nasal  fossas  comnnence  upon  the  face  by  a  large  irregu- 
lar opening, — the  anterior  nares, — and  ternainate  posteriorly  in  the 
two  posterior  nares. 


TEETH. 


Man  is  provided  with  two  successions  of  teeth ;  the  first  are  the 
teeth  of  childhood,  they  are  called  temporary  or  deciduous;  the 
second  continue  until  old  age,  and  are  named  permanent. 

^Fig.  27. 


The  permanent  teeth  are  thirty-two  in  number,  sixteen  in  each 
jaw;  they  are  divisible  into  four  classes, — incisors,  of  which  there 
are  four  in  each  jaw,  two  central  and  two  lateral ;  canine,  two 
above  and  two  below :  bicusj/id,  four  above  and  four  below ;  and 
molars,  six  above  and  six  below. 

The  temporary  teeth  are  twenty  in  number  (fig.  28) ;  eight  incisors, 
four  canine,  and  eight  molars.  The  temporary  molars  have  four 
tubercles,  and  are  succeeded  by  the  permanent  bicuspides,  which 
have  only  two  tubercles. 

Each  tooth  is  divisible  into  a  crown,  which  is  the  part  apparent 
above  the  gum;  a  constricted  portion  around  the  base  of  the 
crown,  the  neck;  and  a  root  or  fang,  which  is  contained  within  the 
alveolus.  The  root  is  invested  by  periosteum,  which  lines  the 
alveolus,  and  is  then  reflected  upon  the  root  of  the  tooth  as  far  us 
its  neck. 

The  incisor  teeth  (cutting  teeth)  are  named  from  presenting  a 
sharp  and  cutting  edge,  formed  at  the  expense  of  the  posterior  sur- 
face.    The  crown  is  flattened  from  before  backwards,  being:  some- 

Fig.  27.  Permanent  teeth,  a.  Central  incisor,  b.  Lateral  incisor,  c.  Cuspid  or 
canine,  d.  Firsl  bicuspid,  e.  Second  bicuspid.  /.  First  molar,  g.  Second  molar. 
h.  Third  molar  or  dens  sapientia. 


84 


STKUCTUKE  OP  TEETH. 


what  convex  in  front  and  concave  behind;  the  neck  is  considerably- 
constricted,  and  the  root  compressed  from  side  to  side ;  at  its  apex 
is  a  small  opening  for  the  passage  of  the  nerve  and  artery  of  the 
tooth. 


Fig.  28. 


The  canine  teeth  (cuspidati)  follow  the  incisors  in  order  from 
before  backwards ;  two  are  situated  in  the  upper  jaw,  one  on  each 
side,  and  two  in  the  lower.  The  crown  is  larger  than  that  of  the 
incisors,  convex  before,  and  concave  behind,  and  tapering  to  a 
blunted  point.  The  root  is  longer  than  that  of  all  the  other  teeth, 
compressed  at  each  side,  and  marked  by  a  slight  groove. 

The  bicuspid  teeth  (small  molars),  two  on  each  side  in  each  jaw, 
follow  the  canine,  and  are  intermediate  in  size  between  them  and 
the  molars.  The  crown  is  compressed  from  before  backwards, 
and  surmounted  by  two  tubercles,  one  internal,  the  other  external ; 
the  neck  is  oval;  the  root  compressed,  and  marked  on  each  side 
by  a  deep  groove,  and  bifid  near  its  apex.  The  teeth  of  the  upper 
jaw  have  a  greater  tendency  to  the  division  of  their  roots  than 
those  of  the  lower,  and  the  posterior  than  the  anterior  pair. 

The  molar  teeth  (grinders,)  three  on  each  side  in  each  jaw,  are 
the  largest  of  the  permanent  set.  The  crown  is  quadrilateral,  and 
surmounted  by  four  tubercles,  the  neck  large  and  round,  and  the 
root  divided  into  several  fangs.  In  the  upper  jaw  the  first  and 
second  molar  teeth  have  three  roots,  sometimes  four,  which  are 
more  or  less  widely  separated  from  each  other,  two  of  the  roots 
being  external,  the  other  internal.  In  the  lower  there  are  but  two 
roots,  which  are  anterior  and  posterior ;  they  are  flattened  from 
behind  forwards,  and  grooved  so  as  to  mark  a  tendency  to  division. 
The  third  molars,  or  denies  sapicnlias,  are  smaller  than  the  other 
two ;  they  present  three  tubercles  on  the  surface  of  the  crown;  and 
the  root  is  single  and  grooved,  appearing  to  be  made  up  of  four 
or  five  fangs  compressed  together,  or  partially  divided.     In  the 


Fig.  28.    Temporary   teeth,    a.  Central   incisor,     b.  Lateral   incisor,    c.  Canine. 
d.  First  molar,     e.  Second  molar. 


STRUCTURE  OP  TEETH. 


85 


lower  jaw  the  fangs  are  frequently  separated  to  some  distance  from 
each  other,  and  much  curved,  so  as  to  offer  considerable  resistance 
in  the  operation  of  extraction.* 

Structiire.-f — The  base  of  the  crown  of  each  tooth  is  hollowed  into 
a  small  cavity,  which  is  continuous  with  a  canal  passing  through  the 
middle  of  each  fang.  The  cavity  and  canal,  or  canals,  constitute  the 
cavitas  pulpse,  and  contain  a  soft  and  secreting  vascular  organ, — 
the  pulp,  which  receives  its  supply  of  vessels  and  nerves  through 
the  small  opening  at  the  apex  of  each  root. 

The  tooth  is  composed  of  three  distinct  structures ;  the  ivory  or 
tooth-bone,  enamel,  and  a  cortical  substance  or  cementum.     The 
ivory   consists  of  microscopic   undulating   and  branching   tubuli, 
which  open  by  their  larger  extremities  upon 
the  walls  of  the  cavitas  pulpse  and  radiate  to-  Fig.  29. 

wards  the  surface  of  the  ivory,  where  they 
terminate  in  ramifications  of  infinite  minute- 
ness. These  tubuli  have  distinct  walls,  are 
separated  from  each  other  by  intervals  equal 
in  breadth  to  the  diameter  of  two  or  three 
tubes,  and  composed  of  dense  dental  sub- 
stance, and  they  contain  within  their  cylin- 
ders a  calcareous  substance  disposed  in  irre- 
gular masses.J  As  the  growth  of  the  tooth 
takes  place  from  the  surface  towards  the 
centre,  the  most  minute  ramifications  are 
first  formed,  and  the  trunks  of  the  tubuli  are 
the  last  deposited. 

The  enamel  forms  a  crust  over  the  whole 
exposed  surface  of  the  crown  of  the  tooth  to 
the  commencement  of  its  root ;  it  is  thickest 
over  the  upper  part  of  the  crown,  and  be- 
comes gradually  thinner  as  it  approaches  the  neck.  It  is  composed 
of  minute  hexagonal  crystalline  fibres,  resting  by  one  extremity 
against  the  surface  of  the  ivory,  and  constituting  by  the  other  the 
free  surface  of  the  crown.  The  enamel  is  separated  from  the  ivory 
by  a  thin  layer  of  membrane,  continuous  with  a  thin  organic  sheath 
which  encloses  each  enamel  fibre,  and  marks  it  by  means  of  trans- 


Fig.  29,  Microscopic  section  of  a  molar  tooth.  1.  Enamel  with  its  columns  and 
laminated  structure.  2.  Cortical  substance  or  cementum  on  the  outside  of  the  fang. 
3.  Ivory,  showing  tubuli.  4.  Foramen  entering  the  dental  cavity  from  the  end  of  the 
fang.  Tliis  fang  has  a  bulbous  enlargement  in  consequence  of  a  hypertrophy  of  the 
cementum.  5.  Dental  cavity.  6.  A  few  osseous  corpuscles  in  the  ivory  just  under  the 
enamel. 

*  See  a  valuable  little  practical  work,  "  On  the  Structure,  Economy,  and  Pathology 
of  the  Teeth,"  by  Mr.  Lintott. 

t  The  structure  of  the  teeth  was  discovered  by  Purkinje  and  Retzius,  and  has  been 
farther  prosecuted  in  this  country  by  Mr.  Nasmyth,  to  whose  beautiful  work,  "Re- 
searches on  the  Developement,  Structure  and  Diseases  of  the  Teeth,"  I  must  refer 
those  who  may  feel  interested  in  this  important  subject. 

t  The  disintegrated  condition  of  the  calcareous  substance  is  probably  the  effect  of 
desiccation;  jt  is  very  remarkable  in  decayed  teeth. 

8 


86  DEVELOPEMENT  OF  TEETH. 

verse  lines  into  irregular  divisions.  Mr.  Nasmyth  is  of  opinion,  that 
the  enamel  is  invested  by  a  thin  layer  of  membrane,  which  is 
continued  over  the  root,  and  is  reflected  through  the  opening  in  the 
apex  of  the  fang  into  the  cavitas  pulpse,  which  it  lines  throughout. 
This  membrane  is  considered  by  Mr.  Nasmyth  to  be  the  "  persistent 
dental  capsule." 

The  cortical  substance,  or  cementum,  forms  a  thin  coating  over 
the  root  of  the  tooth,  from  the  termination  of  the  enamel  to  the 
opening  of  the  apex  of  the  fang.  In  structure  it  consists  of  true 
bone,  characterized  by  the  existence  of  numerous  calcigerous 
cells  and  tubuli.  The  cementum  increases  in  thickness  with  the 
advance  of  age,  and  gives  rise  to  those  exostosed  appearances 
occasionally  seen  in  the  teeth  of  very  old  persons,  or  in  those  who 
have  taken  much  mercury.  In  old  age  the  cavitas  pulp«  is  often 
found  filled  up  and  obliterated  by  osseous  substance  analogous  to 
the  cementum. 

Developement. — The  developement  of  the  teeth  in  the  human  sub- 
ject has  been  most  successfully  investigated  by  our  countryman, 
Mr.  Goodsir,  to  whose  interesting  researches  I  am  indebted  for  the 
following  narrative  :* 

The  inquiries  of  Mr.  Goodsir  commenced  as  early  as  the  sixth 
week  after  conception,  in  an  embryo,  which  measured  seven  lines 
and  a  half  in  length  and  weighed  fifteen  grains.  At  this  early 
period  each  jaw  presents  two  semicircular  folds  around  its  circum- 
ference ;  the  most  external  is  the  true  lip  ;  the  internal,  the  rudiment 
of  the  palate ;  and  between  these  is  a  deep  groove,  lined  by  the 
common  mucous  membrane  of  the  mouth.  A  little  later  a  ridge 
is  developed  from  the  floor  of  this  groove  in  a  direction  from  behind 
forwards,  this  is  the  rudiment  of  the  external  alveolus ;  and  the 
arrangement  of  the  appearances  from  without  inwards  at  this 
period  is  the  following : — Most  externally,  and  forming  the  boun- 
dary of  the  mouth,  is  the  lip ;  next  we  find  a  deep  groove,  which 
separates  the  lip  from  the  future  jaw  ;  then  comes  the  external 
alveolar  ridge ;  fourthly,  another  groove,  in  which  the  germs  of 
the  teeth  are  developed,  the  primitive  dental  groove  ;  fifthly,  a  rudi- 
ment of  the  internal  alveolar  ridge ;  and  sixthly,  the  rudiment  of 
the  future  palate  bounding  the  whole  internally.  At  the  seventh 
week  the  germ  of  the  first  deciduous  molar  of  the  upper  jaw  has 
made  its  appearance,  in  the  form  of  a  "  simple,  free,  granular 
papilla"  of  the  mucous  membrane,  projecting  from  the  floor  of 
the  primitive  dental  groove  ;  at  the  eighth  week,  the  papilla  of  the 
canine  tooth  is  developed ;  at  the  ninth  week  the  papillas  of  the  four 
incisors  (the  middle  preceding  the  lateral)  appear ;  and  at  the  tenth 
week,  the  papilla  of  the  second  molar  is  seen  behind  the  anterior 
molar  in  the  primitive  dental  groove.  So  that  at  this  early  period, 
the  tenth  week,  the  papillas  or  germs  of  the  whole  of  the  ten  deci- 

*  "  On  the  Origin  and  Dcvelopennent  of  the  Pulps  and  Sacs  of  the  Human  Teeth," 
by  John  Goodsir,  jun.,  in  the  Edinburgh  Medical  and  Surgical  Journal,  January  1839, 


DEVELOPEMENT  OF  TEETH.  87 

duous  teeth  of  the  upper  jaw  are  quite  distinct.  Those  of  the  lower 
jaw  are  a  little  more  tardy ;  the  papilla  of  the  first  molar  is  merely 
a  slight  bulging  at  the  seventh  week,  and  the  tenth  papilla  is  not 
apparent  until  the  eleventh  week. 

From  about  the  eighth  week  the  primitive  dental  groove  becomes 
contracted  before  and  behind  the  first  deciduous  molar,  and  laminse 
of  the  mucous  membrane  are  developed  around  the  other  papillae, 
which  increase  in  growth  and  enclose  the  papillee  in  follicles  with 
open  mouths.  At  the  tenth  week  the  follicle  of  the  first  molar  is 
completed,  then  that  of  the  canine;  during  the  eleventh  and  twelfth 
weeks  the  follicles  of  the  incisors  succeed,  and  at  the  thirteenth 
week  the  follicle  of  the  posterior  deciduous  molar. 

During  the  thirteenth  week  the  papillse  undergo  an  alteration  of 
form,  and  assume  the  shape  of  the  teeth  they  are  intended  to  repre- 
sent. And  at  the  same  time  small  membranous  processes  are  de- 
veloped from  the  mouths  of  the  follicles ;  these  processes  are  intended 
to  serve  the  purpose  of  opercula  to  the  follicles,  and  they  correspond 
in  shape  with  the  form  of  the  crowns  of  their  appertaining  teeth. 
To  the  follicles  of  the  incisor  teeth  there  are  two  opercula;  to  the 
canine,  three;  and  to  the  molars  a  number  relative  to  the  number 
of  their  tubercles,  either  four  or  five.  During  the  fourteenth  and 
fifteenth  weeks  the  opercula  have  completely  closed  the  follicles,  so 
as  to  convert  them  into  dental  sacs,  and  at  the  same  time  the  papillse 
have  become  pulps. 

The  deep  portion  of  the  primitive  dental  groove,  viz.  that  which 
contains  the  dental  sacs  of  the  deciduous  teeth,  being  thus  closed  in, 
the  remaining  portion,  that  which  is  nearer  the  surface  of  the  gum, 
is  still  left  open,  and  to  this  Mr.  Goodsir  has  given  the  title  of 
secondary  dental  groove  ;  as  it  serves  for  the  developement  of  all  the 
permanent  teeth,  with  the  exception  of  the  anterior  molars.  During 
the  fourteenth  and  fifteenth  weeks  small  lunated  inflections  of  the 
mucous  membrane  are  formed,  immediately  to  the  inner  side  of  the 
closing  opercula  of  the  deciduous  dental  follicles,  commencing 
behind  the  incisors  and  proceeding  onwards  through  the  rest;  these 
are  the  rudiments  of  the  follicles  or  cavities  of  reserve  of  the  four 
permanent  incisors,  two  permanent  canines,  and  the  four  bicuspides. 
As  the  secondary  dental  groove  gradually  closes,  these  follicular 
inflections  of  the  mucous  membrane  are  converted  into  closed 
cavities  of  reserve,  which  recede  from  the  surface  of  the  gum  and  lie 
immediately  to  the  inner  side  and  in  close  contact  with  the  dental 
sacs  of  the  deciduous  teeth,  being  enclosed  in  their  submucous  cel- 
lular tissue.  At  about  the  fifth  month  the  anterior  of  these  cavities 
of  reserve  dilate  at  their  distal  extremities,  and  a  fold  or  papilla 
projects  into  their  fundus,  constituting  the  rudiment  of  the  germ  of 
the  permanent  tooth  ;  at  the  same  time  two  small  opercular  folds 
are  produced  at  their  proximal  or  small  extremities,  and  convert 
them  into  true  dental  sacs. 

During  the  fifth  month  the  posterior  part  of  the  primitive  dental 
groove  behind  the  sac  of  the  last  deciduous  tooth  has  remained 


DEVELOPEMENT  OF  TEETH. 


open,  and  in  it  has  developed  the  papilla  and  follicle  of  the  first  per- 
manent molar.  Upon  the  closure  of  this  foUicle  by  its  opercula, 
the  secondary  dental  groove  upon  the  summit  of  its  crown  forms  a 
large  cavity  of  reserve,  lying  in  contact  with  the  dental  sac  upon 
the  one  side  and  with  the  gum  upon  the  superficial  side.  At  this 
period  the  deciduous  teeth,  and  the  sacs  of  the  ten  anterior  perma- 
nent teeth,  increase  so  much  in  size,  without  a  corresponding 
lengthening  of  the  jaws,  that  the  first  permanent  molars  are  gra- 
dually pressed  backwards  and  upwards  into  the  maxillary  tubero- 
sity in  the  upper  jaw,  and  into  the  base  of  the  coronoid  process  of 
the  lower  jaw ;  a  position  which  they  occupy  at  the  eighth  and 
ninth  months  of  fcetal  life.  Tn  the  infant  of  seven  or  eight  months 
the  jaws  have  grown  in  length,  and  the  first  permanent  molar 
returns  to  its  proper  position  in  the  dental  range.  The  cavity  of 
reserve,  which  had  been  previously  elongated  by  the  upward  move- 
ment of  the  first  permanent  molar,  now  dilates  into  the  cavity  which 
that  tooth  has  just  quitted ;  a  papilla  is  developed  from  its  fundus, 
the  cavity  becomes  constricted,  and  the  dental  sac  of  the  second 
molar  tooth  is  formed,  still  leaving  a  portion  of  the  great  cavity  of 
reserve  in  connexion  with  the  superficial  side  of  the  sac.  As  the 
jaws  continue  to  grow  in  length,  the  second  permanent  dental  sac 
descends  from  its  elevated  position  and  advances  forwards  into 
the  dental  range,  following  the  same  curve  with  the  first  permanent 
molar.  The  remainder  of  the  cavity  of  reserve,  already  length- 
ened backwards  by  the  previous  position  of  the  second  molar,  again 
dilates  for  the  last  time,  developes  a  papilla  and  sac  in  the  same 
manner  with  the  preceding,  and  forms  the  third  permanent  molar 
or  wisdom  tooth,  which,  at  the  age  of  nineteen  or  twenty,  upon 
the  increased  growth  of  the  jaw,  follows  the  course  of  the  first  and 
second  molars  into  the  dental  range. 

From  a  consideration  of  the  foregoing  phenomena,  Mr.  Goodsir 
has  divided  the  process  of  dentition  into  three  natural  stages : — 
1,  follicular  ;  2,  saccular  ;  3,  eruptive.  The  first,  ov  follicular  stage, 
he  makes  to  include  all  the  changes  which  take  place  from  the 
first  appearance  of  the  dental  groove  and  papillce  to  the  closure 
of  their  follicles ;  occupying  a  period  which  extends  from  the  sixth 
week  to  the  fourth  or  fifth  month  of  intra-uterine  existence.  The 
second,  or  saccular  stage,  comprises  the  period  when  the  follicles 
are  shut  sacs,  and  the  included  papillns,  pulps;  it  commences  at  the 
fourth  and  fifth  months  of  intra-uterine  existence,  and  terminates 
for  the  median  incisors,  at  the  seventh  or  eighth  month  of  infantile 
life,  and  for  the  wisdom  teeth  at  about  the  twenty-first  year.  The 
third,  or  eruj)tive  stage,  includes  the  completion  of  the  teeth,  the 
eruption  and  shedding  of  the  temporary  set ;  the  eruption  of  the  per- 
manent, and  the  necessary  changes  in  the  alveolar  processes.  It 
extends  from  the  seventh  month  till  the  twenty-first  year. 

"  The  anterior  'permanent  molar"  says  Mr.  Goodsir,  "  is  the  most 
remarkable  tooth  in  man,  as  it  forms  a  transition  between  the  milk 
and  the  permanent  set."     If  considered  anatomically,  i.  e.  in  its 


GROWTH  OF  TEETH.  89 

developement  from  the  primitive  dental  groove,  by  a  papilla  and 
follicle,  "  it  is  decidedly  a  milk  tooth ;"  if  physiologically,  "  as  the 
most  efficient  grinder  in  the  adult  mouth,  we  must  consider  it  a  per- 
manent tooth."  "  It  is  a  curious  circumstance,  and  one  which  will 
readily  suggest  itself  to  the  surgeon,  that  laying  out  of  view  the 
wisdom  teeth,  which  sometimes  decay  at  an  early  period  from 
other  causes,  the  anterior  molars  are  the  permanent  teeth  which 
most  frequently  give  way  first,  and  in  the  most  symmetrical  manner 
and  at  the  same  time,  and  frequently  before  the  milk  set." 

Groivih  of  Teeth. — Immediately  that  the  dental  follicles  have  been 
closed  by  their  opercula,  the  pulps  become  moulded  into  the  form  of 
the  future  teeth ;  and  the  bases  of  the  molars  divided  into  two  or 
three  portions,  representing  the  future  fangs.  The  dental  sac  is 
composed  of  two  layers,  an  internal  or  vascular  layer,  which  was 
originally  a  part  of  the  mucous  surface  of  the  mouth,  and  a  cellulo- 
fibrous  layer,  analogous  to  the  corium  of  the  mucous  membrane. 
Upon  the  formation  of  this  sac  by  the  closure  of  the  follicle,  the 
mucous  membrane  resembles  a  serous  membrane  in  being  a  shut  sac, 
and  may  be  considered  as  consisting  of  a  tunica  propria,  which  invests 
the  pulp ;  and  a  tunica  reflexa,  which  is  adherent  by  its  outer  surface 
with  the  structures  in  the  jaw,  and  by  the  inner  surface  is  free,  being 
separated  from  the  pulp  by  an  inter- 
vening cavity.  As  soon  as  the 
moulding  of  the  pulp  has  commenced, 
this  cavity  increases  and  becomes 
filled  with  a  gelatinous  granular  sub- 
stance, the  enamel  organ,  which  is 
adherent  to  the  whole  internal  sur- 
face of  the  tunica  reflexa,  but  not  to 

the  tunica  propria  and  pulp.  At  the  same  period,  viz.,  during  the 
fourth  or  fifth  month,  a  thin  lamina  of  ivory  is  secreted  by  the 
pulp,  and  deposited  upon  its  most  prominent  point:  if  the  tooth 
be  incisor  or  canine,  the  secreted  layer  has  the  form  of  a  small 
hollow  cone ;  if  molar,  there  will  be  four  or  five  small  cones 
corresponding  with  the  number  of  tubercles  on  its  crown.  These 
cones  are  united  by  the  secretion  of  additional  layers,  the  pulp 
becomes  gradually  surrounded  and  diminishes  in  size,  depositing 
fresh  layers  during  its  retreat  into  the  Java's  until  the  entire  tooth 
with  its  fangs  is  completed,  and  the  small  cavitas  pulpse  of  the  per- 
fect tooth  alone  remains,  communicating  through  the  opening  in  the 
apex  of  each  fang  with  the  dental  vessels  and  nerves.  The  number 
of  roots  appears  to  depend  upon  the  number  of  nervous  filaments 
sent  to  each  pulp.  When  the  secretion  of  the  ivory  has  commenced, 
the  enamel  organ  becomes  transformed  into  a  laminated  tissue, 
corresponding  with  the  direction  of  the  fibres  of  the  enamel,  and  the 

Fig.  30.  a.  Capsule  of  a  temporary  incisor  with  the  rudiment  of  the  corresponding 
permanent  tooth  attached,  b.  Capsule  of  a  molar  in  the  same  state.  A  part  of  the 
gum  is  seen  above  it  and  in  contact. 

8* 


90  TEETH ERUPTION. 

crystalline  substance  of  the  enamel  is  secreted  into  its  meshes  by 
the  vascular  lining  of  the  sac. 

The  cementum  appears  to  be  formed  at  a  later  period  of  life,  either 
by  a  deposition  of  osseous  substance  by  that  portion  of  the  dental  sac 
which  continues  to  enclose  the  fang,  and  acts  as  its  periosteum,  or  by 
the  conversion  of  that  membrane  itself  into  bone ;  the  former  suppo- 
sition is  the  more  probable. 

The  secretion  of  ivory  commences  in  the  first  permanent  molar 
previously  to  birth. 

Eruption. — When  the  crown  of  the  tooth  has  been  formed  and 
coated  with  enamel,  and  the  fang  has  grown  to  the  bottom  of  its 
socket  by  the  progressive  lengthening  of  the  pulp,  the  deposition  of 
ivory,  and  the  adhesion  of  the  ivory  to  the  contiguous  portion  of  the 
sac,  the  pressure  of  the  socket  causes  the  reflected  portion  of  the  sac 
and  the  edge  of  the  tooth  to  approach,  and  the  latter  to  pass  through 
the  gum.  The  sac  has  thereby  resumed*  its  original  follicular  con- 
dition, and  has  become  continuous  with  the  mucous  membrane  of  the 
mouth.  The  opened  sac  now  begins  to  shorten  more  rapidly  than  the 
fang  lengthens,  and  the  tooth  is  quickly  drawn  upwards  by  the  con- 
traction, leaving  a  space  between  the  extremity  of  the  unfinished 
root  and  the  bottom  of  the  socket,  in  which  the  growth  a,nd  comple- 
tion of  the  fang  is  more  speedily  effected. 

During  the  changes  which  have  here  been  described  as  taking 
place  among  the  dental  sacs  contained  within  the  jaws,  the  septa 
between  the  sacs,  which  at  first  were  composed  of  spongy  tissue, 
soon  became  fibrous,  and  were  afterwards  formed  of  bone,  which 
was  developed  from  the  surface  and  proceeded  by  degrees  more 
deeply  into  the  jaws,  to  constitute  the  alveoli.  The  sacs  of  the  ten 
anterior  permanent  teeth,  at  first  enclosed  in  the  submucous  cellular 
tissue  of  the  deciduous  dental  sacs,  and  received  during  their  growth 
into  crypts  situated  behind  the  deciduous  teeth,  advanced  by  degrees 
beneath  the  fangs  of  those  teeth,  and  became  separated  from  them 
by  distinct  osseous  alveoli.  The  necks  of  the  sacs  of  the  permanent 
teeth,  by  which  they  originally  communicated  with  the  mucous 
lining  of  the  secondary  groove,  still  exist,  in  the  form  of  minute  ob- 
Fig.  31.  literated  cords,  separated  from  the  deciduous  teeth  by 
their  alveolus,  but  communicating  through  a  minute 
osseous  canal  with  the  fibrous  tissue  of  the  palate,  imme- 
diately behind  the  corresponding  deciduous  teeth. 
"  These  cords  and  foramina  are  not  obliterated  in  the 
child,"  says  Mr.  Goodsir,  "  either  because  the  cords  are 
to  become  useful  as  ^  guhernacula,^  and  the  canals  as 
'  itinera  dentium ;'  or,  much  more  probably,  in  virtue 
of  a  law,  which  appears  to  be  a  general  one  in  the 
developement  of  animal  bodies,  viz. :  that  parts,  or  organs, 

F\g.  31,  Temporary  tooth  with  the  capsule  of  its  permanent  sueecssor  attached  to 
it  by  the  jrubcrnaculum  dcntis. 

*  Mr.  NasmytJi  is  of  opinion  that  it  is  by  "  a  process  of  absorption,  and  not  of  disrup- 
tion, that  the  tooth  ia  emancipated."     Medicochirurgical  Transactions.     1839. 


OS  HYOIDES.  91 

which  have  once  acted  an  important  part,  however  atrophied  they 
may  afterwards  become,  yet  never  altogether  disappear,  so  long  as 
they  do  not  interfere  ivilh  other  parts  or  functions." 

Succession. — The  periods  of  appearance  of  the  teeth  are  extremely- 
irregular  ;  it  is  necessary,  therefore,  to  have  recourse  to  an  average, 
which,  for  the  temporary  teeth,  may  be  stated  as  follows,  the  teeth 
of  the  lower  jaw  preceding  those  of  the  upper  by  a  short  interval : 

7th  month,  two  middle  incisors.     18th  month,  canine. 

9th  month,  two  lateral  incisors.      24th  month,  two  last  molares. 

12th  month,  first  molares. 

The  periods^for  the  permanent  teeth  are, 

6^  year,  first  molares.  10th  year,  second  bicuspides. 

7th  year,  two  middle  incisors.  11th  to  12th  year,  canine. 

8th  year,  two  lateral  incisors.  12th  to  13th  year,  second  molares. 

9th  year,  first  bicuspides.  17th  to  21st  year,  last  molares. 

OS    HYOIDES. 

The  OS  hyoides  forms  the  second  arch  developed  from  the  cranium, 
and  gives  support  to  the  tongue,  and  attachment  to  numerous  mus- 
cles in  the  neck.    It  is  named  from  its  resemblance  to  the  Greek  let- 
ter u,  and  consists  of  a  central  portion,  or 
body,  of  two  larger  cornua,  which  project,  Fig.  32. 

backwards  from  the  body,  and  tw^o  lesser 
cornua,  which  ascend  from  the  angles  of 
union  between  the  body  and  the  greater 
cornua. 

The  body  is  somewhat  quadrilateral,  rough 
and  convex  on  its  anterior  surface,  where  it 
gives  attachment  to  muscles  ;  concave  and 

smooth  on  the  posterior  surface,  by  which  it  lies  in  contact  with  the 
epiglottis.  The  greater  cornua  are  flattened  from  above  downwards, 
and  terminated  posteriorly  in  a  tubercle ;  and  the  lesser  cornua, 
conical  in  form,  give  attachment  to  the  stylo-hyoid  ligaments.  In 
early  age  and  in  the  adult,  the  cornua  are  connected  with  the  body 
by  cartilaginous  surfaces  and  ligamentous  fibres ;  but  in  old  age 
they  become  united  by  bone. 

Devehpement. — ^yfive  centres,  one  for  the  body,  and  one  for 
each  cornu. 

Attachment  of  Muscles. — To  eleven  pairs ;  sterno-hyoid,  thyro- 
hyoid, omo-hyoid,  pulley  of  the  digastricus,  stylo-hyoid,  mylo-hyoid, 
genio-hyoid,  genio-hyo-glossus,  hyo-glossus,  lingualis,  and  middle 
constrictor  of  the  pharynx.  It  also  gives  attachment  to  the  stylo- 
hyoid, thyro-hyoid,  and  hyo-epiglottic  ligaments,  and  to  the  thyro- 
hyoidean  membrane. 

Tig.  32,  The  os  hyoides  seen  from  before.  1.  The  anterior  convex  side  of  the  body, 
2.  The  g^reat  cornu  of  the  left  side.  3.  The  lesser  cornu  of  the  same  side.  The  cornua 
were  ossified  to  the  body  of  the  bone  in  the  specimen  from  which  this  figure  was 
drawn. 


92  THORAX  AND  UPPER  EXTBEMITT. 


THORAX    AND     UPPER     EXTREMITY. 

The  bones  of  the  thorax  are  the  sternum  and  ribs ;  and,  of  the 
upper  extremity,  the  clavicle,  scapula,  humerus,  ulna,  and  radius, 
bones  ofthe  carpus,  metacarpus,  and  phalanges. 

Sternum. — The  sternum  (fig.  33)  is  situated  in  the  middle  line  of 
the  front  of  the  chest ;  it  is  flat,  or  slightly  concave  in  front,  and 
convex  behind ;  broad  and  thick  above,  and  flattened  and  pointed 
below.     It  consists  of  three  pieces ;  superior,  middle,  and  inferior. 

The  superior  (1)  is  nearly  quadrilateral ;  broad  and  thick  above, 
and  somev^'hat  narrowed  at  its  junction  with  the  middle  piece.  At 
each  superior  angle  is  a  deep  articular  depression  for  the  clavicle, 
and  on  either  side  two  notches,  for  the  articulation  of  the  cartilage 
of  the  first  rib,  and  one  half  of  the  second. 

The  middle  piece  (2),  considerably  longer  than  the  superior,  is 
broad  in  the  middle,  and  somewhat  narrower  at  each  extremity. 
It  presents  on  each  side  six  articular  notches,  for  the  lower  half  of 
the  second  rib,  the  four  next  ribs,  and  the  upper  half  of  the  seventh. 

The  inferior  piece,  or  ensiform  cartilage  (3),  is  the  smallest  of  the 
three,  often  merely  cartilaginous,  and  very  various  in  appearance, 
being  sometimes  pointed,  at  other  times  broad  and  thin,  and  at 
other  times  again,  perforated  by  a  round  hole,  or  bifid.  It  presents 
a  notch  at  each  side  for  the  articulation  of  the  lower  half  of  the 
cartilage  of  the  seventh  rib. 

Developement. — By  a  number  of  centres,  varying  from  six  to 
fourteen. 

Articulations. — With  sixteen  bones ;  viz.  with  the  clavicle,  and 
with  seven  true  ribs  at  each  side. 

Attachment  of  Muscles. — To  nine  pairs  and  one  single  muscle ; 
viz.  to  the  pectoralis  major,  sterno-mastoid,  sterno-hyoid,  sterno- 
thyroid, triangularis  sterni,  aponeurosis  of  the  obliquus  externus, 
internus,  and  transversalis  muscles,  rectus,  and  diaphragm. 

Ribs, — The  ribs  are  twelve  in  number  at  each  side;  the  seven 
first  are  connected  with  the  sternum,  and  hence  named  true;  the 
remaining  five  are  the  false  ribs  ;  and  the  two  last  shorter  than  the 
rest,  and  free  at  their  extremities,  are  the  floating  ribs.  The 
ribs  increase  in  length  from  the  first  to  the  eighth,  whence  they 
again  diminish  to  the  twelfth ;  in  breadth  they  diminish  gra- 
dually from  the  first  to  the  last.  Each  rib  presents  an  external 
and  internal  surface,  a  superior  and  inferior  border,  and  two 
extremities ;  it  is  curved  to  correspond  with  the  arch  of  the 
thorax,  and  twisted  upon  itself,  so  that  when  laid  upon  its  side,  one 
end  is  tilted  up,  while  the  other  rests  upon  the  surface. 

The  external  surface  is  convex,  and  marked  by  the  attachment 
of  muscles  ;  the  internal  is  flat,  and  corresponds  with  the  pleura  ; 
the  superior  harder  is  rounded  ;  and  the  inferior  sharp  and  grooved 
upon  its  inner  side,  for  the  attachment  of  the  intercostal  muscles. 
Near  its  vertebral  extremity,  the  rib  is  suddenly  bent  upon  itself; 
and  opposite  the  bend,  upon  the  external  surface,  is  a  rough  oblique 


KIBS — TRUE  AND  FALSE. 


93 


ridge,  which  gives  attachment  to  a  tendon  of  the  sacro-lumbalis  mus- 
cle, and  is  called  the  angle.     The  distance  between  the  vertebral 
extremity  and  the  angle  increases  gradually,  from  the  second  to 
the  eleventh   rib.     Beyond  the 
angle  is  a  rough  elevation,  the  Fig.  33. 

tuberosity ;  and  immediately  at 
the  base  and  rather  belovv^  the 
tuberosity  a  smooth  surface  for 
articulation  with  the  extremity 
of  the  transverse  process  of  the 
corresponding  vertebra.  Beyond 
the  tuberosity  is  the  nech  ;  and 
at  the  extremity  of  the  neck  an 
oval  surface,  the  head,  divided 
by  a  ridge  into  two  facets  for 
articulation  with  two  contiguous 
vertebrae.  The  posterior  surface 
of  the  neck  is  rough,  for  the  at- 
tachment of  the  middle  costo- 
transverse ligament;  and  upon 
its  upper  border  is  a  crest,  which 
gives  attachment  to  the  anterior 
costo-transverse  ligament.  The 
sternal    extremity   is    flattened, 

and  presents  an  oval  depression,  into  which  the  costal  cartilage  is 
received. 

The  ribs  that  demand  especial  consideration  are  the  first,  and  the 
three  last. 

The  first  is  the  shortest  rib ;  it  is  broad  and  flat,  and  placed  hori- 
zontally at  the  upper  part  of  the  thorax,  the  surfaces  looking  up- 
wards and  downwards,  in  place  of  forwards  and  backwards  as  in 
the  other  ribs.  At  about  the  anterior  third  of  the  upper  surface  of 
the  bone,  and  near  its  internal  border,  is  a  tubercle  which  gives  at- 
tachment to  the  scalenus  anticus  muscle,  and  immediately  before 
and  behind  this  tubercle,  a  shallow  oblique  groove,  the  former  for 
the  subclavian  vein,  and  the  latter  for  the  subclavian  artery.  Near 
the  posterior  extremity  of  the  bone  is  a  thick  and  prominent  tube- 
rosity, with  a  smooth  articular  surface  for  the  transverse  process  of 
the  first  dorsal  vertebra.  There  is  no  angle.  Beyond  the  tube- 
rosity is  a  narrow  constricted  neck ;  and  quite  at  the  extremity,  a 
head,  presenting  a  single  articular  surface.  The  second  rib  ap- 
proaches in  some  of  its  characters  to  the  first. 


Fig.  33.  An  anterior  view  of  the  thorax.  1.  The  superior  piece  of  the  sternnm 
2.  The  middle  piece.  3.  The  inferior  piece,  or  ensiform  cartilage.  4.  The  first  dorsal 
vertebra.  5.  The  last  dorsal  vertebra.  6.  The  first  rib.  7.  Its  head.  8.  Its  neck, 
resting  against  the  transverse  process  of  the  first  dorsal  vertebra.  9.  Its  tuberosity. 
10.  The  seventh  or  last  true  rik  11.  The  costal  cartilages  of  the  true  ribs.  12.  The 
two  last  false  ribs — the  floating  ribs.  13.  The  groove  along  the  lower  border  of  the 
rib  for  the  lodgment  of  the  intercostal  vessels  and  nerve. 


94  COSTAL  CARTILAGES. 

The  tenth  rib  has  a  single  articular  surface  on  its  head. 

The  eleventh,  and  twelfth  have  each  a  single  articular  surface  on 
the  head,  no  neck  or  tuberosity,  and  are  pointed  at  the  extremity. 
The  eleventh  has  a  slight  ridge,  representing  the  angle,  and  a  shal- 
low groove  on  the  lower  border;  the  twelfth  has  neither. 

Costal  Cartilages. — The  costal  cartilages  (fig.  33.  11,  11)  serve 
to  prolong  the  ribs  forwards  to  the  anterior  part  of  the  chest,  and 
contribute  mainly  to  the  elasticity  of  the  thorax.  They  are  bi'oad 
at  their  attachment  to  the  ribs,  and  taper  slightly  towards  their  oppo- 
site extremities ;  they  gradually  diminish  in  breadth  from  the  first  to 
the  last,  and  increase  in  length  from  the  first  to  the  seventh,  and  then 
diminish  to  the  last. 

The  seven  first  cartilages  articulate  with  the  sternum  ;  the  three 
next  with  the  lower  border  of  the  cartilage  immediately  preceding. 
All  the  cartilages  of  the  false  ribs  terminate  by  pointed  extremities. 

Developement — The  ribs  are  developed  by  three  centres ;  one  for 
the  central  part,  one  for  the  head,  and  one  for  the  tuberosity.  The 
two  last  have  only  one  centre. 

Articulations. — Each  rib  articulates  with  two  vertebrse,  and  one 
costal  cartilage,  with  exception  of  the  first,  tenth,  eleventh,  and 
twelfth,  which  articulate  each  with  a  single  vertebra  only. 

Attachment  of  Muscles. — To  the  ribs  and  their  cartilages  are  at- 
tached twenty-tico  pairs,  and  one  single  muscle.  To  the  cartilages, 
the  subclavius,  sterno-thyroid,pectoralis  major,  internal  oblique,  rec- 
tus, transversalis,  diaphragm,  triangularis  sterni,  internal  and  exter- 
nal intercostals.  To  the  ribs,  the  intercostal  muscles,  scalenus 
anticus,  scalenus  posticus,  pectoralis  minor,  serratus  magnus,  obli- 
quus  externus,  obliquus  internus,  latissimus  dorsi,  quadratus  lumbo- 
rum,  serratus  posticus  superior,  serratus  posticus  inferior,  sacro- 
lumbalis,  longissimus  dorsi,  cervicalis  ascendens,levatores  costarum, 
transversalis,  and  diaphragm. 

Clavicle. — The  clavicle  is  a  long  bone  shaped  somewhat  like  the 
italic  letter  S,  the  convexity  at  one  end  being  anterior  and  internal, 
at  the  other  posterior  and  external.  The  inner  half  of  the  bone  is 
rounded  or  irregularly  quadrilateral,  and  terminates  in  a  broad  arti- 
cular surface.  The  outer  half  is  flattened  from  above  downwards, 
and  broad  at  its  extremity,  the  articular  surface  occupying  only  part 
of  its  extent.  The  upper  surface  is  smooth  and  convex,  and  partly 
subcutaneous ;  while  the  under  surface  is  rough  and  depressed,  for 
the  insertion  of  the  subclavius  muscle.  At  the  sternal  extremity  of 
the  under  surface  is  a  very  rough  prominence,  which  gives  attach- 
ment to  the  rhomboid  ligament ;  and  at  the  other  extremity  a  rough 
tubercle  and  ridge,  for  the  coraco-clavicular  ligament.  The  open- 
ing for  the  nutritious  vessels  is  seen  upon  the  under  surface  of  the 
bone. 

Developement. — By  two  centres  ;  one  for  the  shaft, and  one  for  the 
anterior  prominence  of  the  sternal  extremity. 

Jlrticvlations. — With  the  sternum  and  scapula. 

Attachment  of  Muscles. — To  six;  the  sterno-mastoid,  trapezius, 
pectoralis  major,  deltoid,  subclavius,  and  sterno-hyoid. 


SCAPULA. 


95 


Fig.  34. 


Scapula. — The  scapula  is  a  flat  triangular  bone,  situated  upon  the 
posterior  aspect  and  side  of  the  thorax.  It  is  divisible  into  an  ante- 
rior and  posterior  surface,  superior,  inferior,  and  posterior  border, 
anterior,  superior,  and  inferior  angle  and  processes. 

The  anterior  surface,  or  subscapular  fossa,  is  concave  and  irregu- 
lar, and  marked  by  several  oblique  ridges.  The  whole  concavity  is 
occupied  by  the  subscapularis  muscle,  with  the  exception  of  a  small 
triangular  portion  near  the  superior  angle.  The  posterior  surface 
or  dorsum  is  convex,  and  unequally  divided  into  two  portions  by  the 
spine  ;  that  portion  above  the  spine  is  the  supra-spinous  fossa  ;  and 
that  below,  the  infra-spinous  fossa. 

The  superior  border  is  the  shortest  of  the  three ;  it  is  thin  and  con- 
cave, and  terminated  at  one  extremity  by  the  superior  angle,  and 
at  the  other  by  the  coracoid  process.  At  its  inner  termination,  and 
formed  partly  by  the  base  of  the  coracoid  process,  is  the  supra-sca- 
pular notch,  for  the  transmission  of  the  supra-scapular  nerve. 

The  inferior  or  anterior  border  is  thick,  and  marked  by  several 
grooves  and  depressions;  it  terminates  superiorly  at  the  glenoid 
cavity,  and  inferiorly  at  the  inferior  angle.  Immediately  below  the 
glenoid  cavity  is  a  rough  ridge,  which  gives  origin  to  the  long  head 
of  the  triceps  muscle.  Upon  the  poste- 
rior surface  of  the  border  is  a  depression 
for  the  teres  minor ;  and  upon  its  ante- 
rior surface  a  deeper  groove  for  the 
teres  major  ;  near  the  inferior  angle  is 
a  projecting  lip,  which  increases  the  sur- 
face of  origin  of  the  latter  muscle.  The 
posterior  border,  the  longest  of  the  three 
is  also  named  the  base.  It  is  interme- 
diate in  thickness  between  the  supe- 
rior and  inferior,  and  convex,  being 
considerably  inflected  forwards  towards 
the  superior  angle. 

The  anterior  angle  is  the  thickest 
part  of  the  bone,  and  forms  the  head 
of  the  scapula;  it  is  immediately 
surrounded  by  a  depressed  surface, 
the  necJi.  The  head  presents  a  shal- 
low pyriform  articular  surface,  the 
glenoid  cavity,  having  the  pointed  ex- 
tremity upwards ;  and  at  its  apex  is  a  rough  depression,  which 
gives  attachment  to  the  long  tendon  of  the  biceps.     The  superior 

Fi^.  34.  A  posterior  view  of  tlie  scapula.  1.  Tlie  supra-spinous  fossa.  2.  The  infra- 
spinous  foesa.  3.  The  superior  border.  4.  The  supra-scapular  notch.  5.  The 
anterior  or  inferior  border.  6.  The  head  of  the  scapula  and  glenoid  cavity.  7.  The 
inferior  angle.  8.  The  neck  of  the  scapula,  the  ridge  opposite  to  the  number  gives 
origin  to  the  long  head  of  the  triceps.  9.  The  posterior  border  or  base  of  the  scapula. 
10.  The  spine.  11.  The  triangular  smooth  surface,  over  which  the  tendon  of  the 
trapezius  glides.  12.  The  acromion  process.  13.  One  of  the  nutritious  foramina. 
14.  The  coracoid  process. 


96  HUMERUS. 

angle  is  thin  and  pointed.  The  inferior  angle  is  thick  and  smooth 
upon  the  external  surface  for  the  origin  of  the  teres  major,  and  for 
a  large  bursa  over  which  the  upper  border  of  the  latissimus  dorsi 
muscle  plays. 

The  spine  of  the  scapula  crosses  the  upper  part  of  its  dorsum ; 
it  commences  at  the  posterior  border  by  a  smooth  triangular 
surface  over  which  the  trapezius  glides  upon  a  bursa,  and  termi- 
nates at  the  point  of  the  shoulder  in  the  acromion  process.  The 
upper  border  of  the  spine  is  rough  and  subcutaneous,  and  gives 
attachment  by  two  projecting  lips  to  the  trapezius  and  deltoid 
nnuscles. 

The  acromion  is  somewhat  triangular  and  flattened  from  above 
downwards;  it  overhangs  the  glenoid  cavity,  the  upper  surface 
being  rough  and  subcutaneous,  the  lower  smooth  and  correspond- 
ing with  the  shoulder-joint.  Near  its  extremity  is  an  oval  articular 
surface,  for  the  end  of  the  clavicle.  The  nutritious  foramina  of 
the  scapula  are  situated  in  the  base  of  the  spine. 

The  coracoid  process  is  a  thick,  round,  and  curved  process  of 
bone  arising  from  the  upper  part  of  the  neck  of  the  scapula,  and 
overarching  the  glenoid  cavity.  It  is  about  two  inches  in  length 
and  very  strong ;  it  gives  attachment  to  several  ligaments  and 
muscles. 

Devehpement — By  six  centres ;  one  for  the  body,  one  for  the 
coracoid  process,  two  for  the  acromion,  one  for  the  posterior  border, 
and  one  for  the  inferior  angle. 

Articulations. — With  the  clavicle  and  humerus. 

Attachment  of  Muscles. — To  sixteen ;  by  its  anterior  surface  to 
the  subscapularis ;  posterior  surface,  supra-spinatus  and  infra-spi- 
natus ;  superior  border,  omo-hyoid ;  posterior  border,  levator  an- 
guli  scapulae,  rhomboideus  minor,  rhomboideus  major,  and  serratus 
magnus ;  anterior  border,  long  head  of  the  triceps,  teres  minor,  and 
teres  major  ;  upper  angle  of  the  glenoid  cavity,  to  the  long  tendon 
of  the  biceps ;  spine  and  acromion,  to  the  trapezius  and  deltoid ; 
coracoid  process,  to  the  pectoralis  minor,  short  head  of  the  biceps, 
and  coraco-brachialis.  The  ligaments  attached  to  the  coracoid 
process  are,  the  coracoid,  coraco-clavicular,  and  coraco-humeral, 
and  the  costo-coracoid  membrane. 

Humerus. — The  humerus  is  a  long  bone  divisible  into  a  shaft  and 
two  extremities. 

The  superior  extremity  presents  a  rounded  head ;  a  constriction 
immediately  around  the  base  of  the  head,  the  neck  ;  a  greater  and 
a  lesser  tuberosity.  The  greater  tuberosity  is  situated  most  exter- 
nally, and  is  separated  from  the  lesser  by  a  vertical  furrow — the 
bicipital  groove, — which  lodges  the  long  tendon  of  the  biceps.  The 
edges  of  this  groove  below  the  head  of  the  bone  are  raised  and 
rough,  and  are  called  the  anterior  and  posterior  bicipital  ridge ;  the 
former  serves  for  the  insertion  of  the  pectoralis  major  muscle,  and 
the  latter  for  the  teres  major. 

The  constriction  of  the  bone  below  the  tuberosities  is  the  sur- 


HUMERUS. 


97 


si^'-.-^ 


gical  neck,  and  is  so  named,  in  contradistinction  to  the  true  neck, 
from  being  the  seat  of  the  accident  called  by  surgical  writers //-ac- 
ture  of  the  neck  of  the  humerus.  ' 

The  shaft  of  the  bone  is  prismoid  at  its  upper  part,  and  flattened 
from  before  backwards  below.  Upon  its  outer  side,  at  about  its 
middle,  is  a  rough  triangular  eminence,  which  gives  insertion  to 
the  deltoid  ;  and  immediately  on  each  side  of  this  eminence  is  a 
smooth  depression,  corresponding  with  the  two  heads  of  the  bra- 
chialis  anticus.  Upon  the  inner  side  of  the  middle  of  the  shaft  is  a 
ridge,  for  the  attachment  of  the  coraco-brachialis  muscle  ;  and 
behind,  an  oblique  and  shallow-groove,  which  lodges  the  musculo- 
spiral  nerve  and  superior  profunda  artery.  The  foramen  for  the 
medullary  vessels  is  situated  upon  the  inner  surface  of  the  shaft  of 
the  bone,  a  little  below  the  coraco-brachial  ridge ;  it  is  directed 
downwards. 

The  lower  extremity  is  flattened  from  before  backwards,  and  is 
terminated  inferiorly  by  a  long  articular  surface,  divided  into  two 
parts  by  an  elevated  ridge.  The  external  portion 
of  the  articular  surface  is  a  rounded  protuberance,  F»g-  35. 
which  articulates  with  the  cup-shaped  depression 
on  the  head  of  the  radius  ;  the  internal  portion  is  a 
concave  and  pulley-like  surface,  which  articulates 
with  the  ulna.  Projecting  beyond  the  articular 
surface  on  each  side  are  the  external  and  internal 
condyle,  the  latter  being  considerably  the  longer ; 
and  running  upwards  from  the  condyles  upon  the 
borders  of  the  bone  are  the  condyloid  ridges,  of 
which  the  external  is  the  most  prominent.  Immedi- 
ately in  front  of  the  articular  surface  is  a  small  de- 
pression, for  receiving  the  coronoid  process  of  the 
ulna  during  flexion  of  the  fore-arm ;  and  immedi- 
ately behind  it  a  large  and  deep  fossa,  for  containing 
the  olecranon  process  in  extension. 

Developement. — By  seven  centres ;  one  for  the 
shaft,  one  for  the  upper  extremity,  one  for  the 
greater  tuberosity,  one  for  the  rounded  protuberance, 
and  one  for  the  trochlear  portion  of  the  articular 
surface,  and  one  for  each  condyle. 

Articulations. — With  the  glenoid  cavity  of  the 
scapula,  and  with  the  ulna  and  radius. 

Attachment  of  Muscles. — To  twenty-four  ;  by  the 
greater  tuberosity  to  the  supra-spinatus,  infra-spina- 

Fig;.  35.  The  humerus  of  the  riglit  side;  its  anterior  surface.  1.  the  shaft  of  the 
bone.  2.  The  head.  3.  The  anatomical  neck.  4.  The  greater  tuberosity.  5.  The 
lesser  tuberosity.  6.  The  bicipital  groove.  7.  The  anterior  bicipital  ridge.  8.  The 
posterior  bicipital  ridge.  9.  The  rough  surface  into  which  the  deltoid  is  inserted.  10. 
The  nutritious  foramen.  11.  The  rounded  protuberance  of  tlie  articular  surface. 
12.  The  pulley-like  surface.  13.  The  external  condyle.  14.  The  internal  condyle.  15. 
The  external  condyloid  ridge.  16.  The  internal  condyloid  ridge.  17.  The  ibssa  for 
the  coronoid  process  of  the  ulna. 

9 


98  riNA. 

tus,  and  teres  minor ;  lesser  tuberosity,  subscapularis ;  anterior  bi- 
cipital ridge,  pectoralis  major  ;  posterior  bicipital  ridge  and  groove, 
teres  major  and  latissimus  dorsi ;  shaft,  external  and  internal  heads 
of.  the  triceps,  deltoid,  coraco-brachialis,  and  brachialis  anticus  ; 
external  condyloid  ridge  and  condyle,  extensors  and  supinators  of 
the  forearm,  viz.  supinator  longus,  extensor  carpi  radialis  longior, 
extensor  carpi  radialis  brevior,  extensor  communis  digitorum,  ex- 
tensor minimi  digiti,  extensor  carpi  ulnaris,  anconeus  and  supinator 
brevis;  internal  condyle,  flexors  and  one  pronator,  viz.  pronator 
radii  teres,  flexor  carpi  radialis,  palmaris  longus,  flexor  sublimis 
digitorum,  and  flexor  carpi  ulnaris. 

Ulna. — The  ulna  is  a  long  bone,  divisible  into  a  shaft  and  two 
extremities.  The  upper  extremity  is  large,  and  forms  principally 
the  articulation  of  the  elbow ;  while  the  lower  extremity  is  small, 
and  excluded  from  the  wrist-joint  by  an  inter-articular  fibro- 
cartilage. 

The  superior  extremity  presents  a  semilunar  concavity  of  large 
size,  the  greater  sigmoid  notch,  for  articulation  with  the  humerus ; 
and  upon  the  outer  side  a  lesser  sigmoid  notch,  which  articulates 
with  the  head  of  the  radius.  Bounding  the  greater  sigmoid  notch 
posteriorly  is  the  olecranon  process  ;  and  overhanging  it  in  front,  a 
pointed  eminence  with  a  rough  triangular  base — the  coronoid  process. 
Behind  the  lesser  sigmoid  notch,  and  extending  downwards  on  the 
side  of  the  olecranon,  is  a  triangular  rough  surface,  for  the  an- 
coneus muscle;  and  upon  the  posterior  surface  of  the  olecranon 
another  triangular  surface,  which  is  subcutaneous. 

The  shaft  is  prismoid  in  form,  and  presents  three  surfaces, — an- 
terior, posterior,  and  internal ;  and  three  borders.  The  anterior 
surface  is  occupied  by  the  flexor  profundus  digitorum  for  the  upper 
■  three-fourths  of  its  extent ;  and  below  by  a  depression,  for  the  pro- 
nator quadratus  muscle.  A  little  above  its  middle  is  the  nutritious 
foramen,  which  is  directed  upwards.  Upon  the  posterior  surface  at 
the  upper  part  of  the  bone  is  the  triangular  rough  depression  for  the 
anconeus  muscle,  bounded  inferiorly  by  an  oblique  ridge  which 
runs  downwards  from  the  posterior  extremity  of  the  lesser  sigmoid 
notch.  Below  the  ridge  the  surface  is  marked  into  several  grooves, 
for  the  attachment  of  the  extensor  ossis  metacarpi,  extensor  secundi 
internodii,  and  extensor  indicis  muscle.  The  internal  surface  is 
covered  in  for  its  whole  extent  by  the  flexor  carpi  ulnaris. 
The  anterior  border  is  rounded,  and  gives  origin  by  its  lower  fourth 
to  the  pronator  quadratus  ;  the  posterior  is  more  prominent,  and 
affords  attachment  to  the  flexor  carpi  ulnaris  and  extensor  carpi 
ulnaris.  At  its  upper  extremity  it  expands  into  the  triangular  sub- 
cutaneous surface  of  the  olecranon.  The  external  or  radial  border 
is  sharp  and  prominent,  for  the  attachment  of  the  interosseous 
membrane. 

The  lower  extremity  terminates  in  a  small  rounded  head,  from  the 
side  of  which  projects  the  styloid  process.  Upon  the  posterior 
surface  of  the  head  is  a  groove  for  the  tendon  of  the  flexor  carpi 


BADIUS. 


99 


Fig.  36. 


ulnaris ;  and  upon  the  side  opposite  to  the  styloid  process  a  smooth 
surface,  for  articulation  with  the  side  of  the  radius. 

Devehpement. — By  four  centres  ;  one  for  the  shaft,  one  for  each 
extremity,  and  one  for  the  olecranon. 

Articulations. — With  tico  bones;  the  humerus  and  radius. 

Attachment  of  Muscles, — To  twelve ;  by  the  olecranon,  to  the 
triceps  extensor  cubiti,  one  head  of  the  flexor  carpi  ulnaris,  and  to 
the  anconeus  ;  by  the  coronoid  process,  to  the  brachialis  anticus, 
pronator  radii  teres,  flexor  sublimis  digitorum,  and  flexor  profundus 
digitorum  ;  by  the  shaft,  to  the  flexor  profundus  digitorum,  flexor 
carpi  ulnaris,  pronator  quadratus,  anconeus,  extensor  carpi  ulnaris, 
extensor  ossis  metacarpi  pollicis,  extensor  secundi  internodii  pollicis, 
and  extensor  indicis. 

Radius. — The  radius  is  the  rotatory  bone  of  the  fore-arm  ;  it  is 
divisible  into  a  shaft  and  two  extremities :  unlike  the  ulna,  its  upper 
extremity  is  small,  and  merely  accessory  to  the  formation  of  the 
elbow-joint;  while  the  lower  extremity  is  large,  and 
forms  almost  solely  the  joint  of  the  wrist. 

The  su-perior  extremity  presents  a  rounded  head, 
depressed  upon  its  upper  surface  into  a  shallow  cup. 
Around  the  margin  of  the  head  is  a  smooth  articular 
surface,  which  is  broad  on  the  inner  side,  where  it 
articulates  with  the  lesser  sigmoid  notch  of  the  ulna, 
and  narrow  in  the  rest  of  its  circumference,  to  play 
in  the  orbicular  ligament.  Beneath  the  head  is  a 
round  constricted  neck ;  and  beneath  the  neck  on  its 
internal  aspect  a  prominent  process — the  tuberosity. 
The  surface  of  the  tuberosity  is  partly  smooth,  and 
partly  rongh  ;  rough  below,  where  it  receives  the  at- 
tachment of  the  tendon  of  the  biceps  ;  and  smooth 
above,  where  a  bursa  is  interposed  between  the  ten- 
don and  the  bone. 

The  shaft  of  the  bone  is  prismoid,  and  presents 
three  surfaces.  The  anterior  surface  is  somewhat 
concave  superiorly,  w'here  it  lodges  the  flexor  longus 
pollicis  ;  and  flat  below,  where  it  supports  the  pro- 
nator quadratus.  At  about  the  upper  third  of  this 
surface  is  the  nutritious  foramen,  which  is  directed 
upwards.  H^hefosteriorsurfaceis  round  above, where 
it  supports  the  supinator  brevis  muscle,  and  marked  by  several  shal- 
low oblique  grooves  below,  which  aflford  attachment  to  the  extensor 


Fig.  36.  The  two  bones  of  the  fore-arm  seen  from  the  front.  1.  The  shaft  of  the 
ulna.  2.  The  greater  sigmoid  notch.  3.  The  lesser  sigmoid  notch,  with  which  the 
head  of  the  radius  is  articulated.  4.  The  olecranon  process.  5.  The  coronoid  process. 
6.  The  nutritious  foramen.  7.  The  sharp  ridges  upon  the  two  bones  to  which  the 
interosseous  membrane  is  attached.  8.  The  rounded  head  at  the  lower  extremity  of 
the  ulna.  9.  The  styloid  process.  10.  The  shaft  of  the  radius.  11.  Its  head  sur- 
rounded by  the  smooth  border  for  articulation  with  the  orbicular  ligament.  12.  The 
neck  of  the  radius.  13.  Its  tuberosity.  14.  The  oblique  line.  15.  The  lower  extremity 
of  the  bone.     16.  Its  styloid  process. 


100  CARPUS. 

muscles  of  the  thumb.  The  external  surface  is  rounded  and  con- 
vex, and  marked  by  an  oblique  ridge,  which  extends  from  the  tube- 
rosity to  the  styloid  process  at  the  lower  extremity  of  the  bone. 
Upon  the  inner  margin  of  the  bone  is  a  sharp  and  prominent  crest, 
which  gives  attachinent  to  the  interosseous  membrane.  The  lower 
extremity  of  the  radius  is  broad  and  triangular,  and  provided  with 
two  articular  surfaces ;  one  at  the  side  of  the  bone,  which  is  con- 
cave to  receive  the  rounded  head  of  the  ulna  ;  the  other  at  the  ex- 
tremity, and  marked  by  a  slight  ridge  into  two  facets, — one  exter- 
nal and  triangular,  corresponding  with  the  scaphoid ;  the  other 
square,  with  the  semilunar  bone.  Upon  the  outer  side  of  the  ex- 
tremity is  a  strong  conical  projection,  the  styloid  process,  which 
gives  attachment  by  its  base  to  the  tendon  of  the  supinator  longus, 
by  its  apex  to  the  external  lateral  ligament  of  the  wrist  joint,  and  by 
its  inner  side  to  the  triangular  interarticular  cartilage. 

Immediately  in  front  of  the  styloid  process  is  a  groove,  which 
lodges  the  tendons  of  the  extensor  ossis  metacarpi  pollicis,  and  ex- 
tensor primi  internodii :  and  behind  the  process  a  broader  groove, 
for  the  tendons  of  the  extensor  carpi  radialis  longior  and  brevior,  and 
extensor  secundi  internodii ;  behind  this  is  a  prominent  ridge,  and  a 
deep  and  narrow  groove,  for  the  tendon  of  the  extensor  indicis;and 
still  farther  back  part  of  a  broad  groove,  completed  by  the  ulna,  for 
the  tendons  of  the  extensor  communis  digitorum. 

Beoelopement. — By  three  centres  ;  one  for  the  shaft,  and  one  for 
each  extremity. 

Articulations. — With  four  bones  ;  humerus,  ulna,  scaphoid,  and 
semilunar. 

Attachment  of  Muscles. — To  nine ;  by  the  tuberosity  and  oblique 
ridge,  to  the  biceps,  supinator  brevis,  pronator  radii  teres,  flexor  sub- 
limis  digitorum,  and  pronator  quadratus  ;  by  the  anterior  surface,  to 
the  flexor  longus  pollicis  and  pronator  quadratus ;  by  the  posterior 
surface,  to  the  extensor  ossis  metacarpi  pollicis,  and  extensor  primi 
internodii;  and  by  the  styloid  process,  to  the  supinator  longus. 

Carpus. — The  bones  of  the  carpus  are  eight  in  number,  they  are 
arranged  in  two  rows.  In  the  first  row,  commencing  from  the 
radial  side,  are  the  os  scaphoides,  semilunare,  cuneiforme,  pisiforme; 
and  in  the  second  row,;in  the  same  order,  the  os  trapezium,  trape- 
zoides,  OS  magnum  and  unciforme. 

The  scaphoid  bone  is  named  from  bearing  some  resemblance  to 
the  shape  of  a  boat,  being  broad  at  one  end,  narrowed  like  a  prow, 
at  the  opposite,  concave  on  one  side,  and  convex  upon  the  other. 
It  is,  however,  more  similar  in  form  to  a  cashew  nut,  flattened  and 
concave  upon  one  side.  If  carefully  examined,  it  will  be  found  to 
present  a  convex  and  a  concave  surface,  a  convex  and  a  concave 
border,  a  broad  end,  and  a  narrow  and  pointed  extremity — the  tube- 
rosity. 

To  ascertain  to  which  hand  it  belongs,  let  the  student  hold  it 
horizontally,  so  that  the  convex  surface  may  look  backwards  {i.  e. 
towards  himself,)  and  the  convex  border  upwards ;  the  broad  ex- 


SCAPHOID  BONE — SEMILUNARE CUNEIFORME. 


101 


Fig.  37. 


tremity  will  indicate  its  appropriate  hand;  if  it  be  directed  to  the 
right,  the  bone  belongs  to  the  right;  and  if  to  the  left,  to  the  left 
carpus. 

Articulations. — With  jive  bones  ;  by  its 
convex  surface  with  the  radius ;  by  its 
concave  surface,  with  the  os  magnum  and 
semilunare ;  and  by  the  extremity  of  its 
upper  or  dorsal  border,  with  the  trapezium 
and  trapezoides. 

Attachments. — By  its  tuberosity  to  the 
abductor  pollicis,  and  annular  ligament. 

The  semilunar  bone  may  be  known  by 
having  a  crescentic  concavity,  and  a 
somewhat  crescentic  outline.  It  presents 
for  examination  four  articular  surfaces 
and  two  extremities;  the  articular  sur- 
faces are,  one  concave,  one  convex,  and 
two  lateral — one  lateral  surface  being 
crescentic ;  the  other  nearly  circular,  and 
divided  generally  into  two  facets :  and  the  extremities,  one  dorsal, 
which  is  quadrilateral,  flat,  and  indented,  for  the  attachment  of 
ligaments  ;  the  other  palmar,  which  is  convex,  rounded,  and  of 
larger  size. 

To  determine  to  which  hand  it  belongs,  let  the  bone  be  held  per- 
pendicularly, so  that  the  dorsal  or  flat  extremity  look  upwards,  and 
the  convex  side  backwards  (towards  the  holder).  The  circular 
lateral  surface  will  point  to  the  side  corresponding  with  the  hand  to 
which  the  bone  belongs. 

Articulations. — With  jive  bones,  but  occasionally  with  only  four ; 
by  its  convex  surface,  with  the  radius ;  by  its  concave  surface, 
with  the  OS  magnum  ;  by  its  crescentic  lateral  facet,  with  the  sca- 
phoid ;  and  by  the  circular  surface,  with  the  cuneiform  bone  and 
with  the  point  of  the  unciform.  This  surface  is  divided  into  two 
parts  by  a  ridge,  when  it  articulates  with  the  unciform  as  well  as 
with  the  cuneiform  bone. 

The  cuneiform  bone,  although  somewhat  wedge-shaped  in  form, 
may  be  best  distinguished  by  a  circular  and  isolated  facet,  which 
articulates  with  the  pisiform  bone.  It  presents  for  examination 
three  surfaces,  a  base  and  an  apex.  One  surface  is  very  rough 
and   irregular ;  the  opposite  forms  a  concave   articular  surface, 


Fig.  37.  A  diagram  showing  the  dorsal  surface  of  the  bones  of  the  carpus,  with  their 
articulations. — The  right  hand.  2.  The  lower  end  of  the  radius.  1.  The  lower  ex- 
tremity of  the  ulna.  3.  The  inter-articular  fibro-cartilage  attached  to  the  styloid  pro- 
cess ol'  the  ulna,  and  to  the  margin  of  the  articular  surface  of  the  radius.  S.  The 
scapliofd  bone.  L.  The  semilunare  articulating  with  five  bones.  C.  The  cuneiforme, 
articulating  with  three  bones.  P.  The  pisiforme,  articulating  with  the  cuneiforme 
only.  T.  The  first  bone  of  the  second  row — the  trapezium,  articulating  with  four 
bones.  T.  The  second  bone — the  trapezoides,  articulating  also  with  four  bones.  M. 
The  OS  magnum,  articulating  with  .seven.     U.  The  uncifonne  articulating  with  five. 

9* 


102  TRAPXIZIUM — TRAPEZOIDES. 

while  the  third  is  partly  rough  and  partly  smooth,  and  presents 
that  circular  facet  which  is  characteristic  of  the  bone.  The  base 
is  an  articular  surface,  and  the  apex  is  rough  and  pointed. 

To  distinguish  its  appropriate  hand,  let  the  base  be  directed 
backwards  and  the  pisiform  facet  upwards  ;  the  concave  articular 
surface  will  point  to  the  hand  to  which  it  belongs. 

Articulations. — With  three  bones,  and  with  the  triangular  fibro- 
cartilage.  By  the  base,  with  the  semilunare  ;  by  the  concave  sur- 
face, with  the  unciforme;  by  the  circular  facet,  with  the  pisiforme ; 
and  by  the  superior  angle  of  the  rough  surface,  with  the  fibro- 
cartilage. 

The  pisiform  bone  may  be  recognised  by  its  small  size,  and  by 
possessing  a  single  articular  facet.  If  it  be  examined  carefully,  it 
will  be  observed  to  present  four  sides  and  two  extremities;  one 
side  is  articular,  the  smooth  facet  approaching  nearer  to  the 
superior  than  the  inferior  extremity.  The  side  opposite  to  this  is 
I'ounded,  and  the  remaining  sides  are,  one  slightly  concave,  the 
other  slightly  convex. 

If  the  bone  be  held  so  that  the  articular  facet  shall  look  down- 
wards, and  the  extremity  which  overhangs  the  articular  facet 
forwards,  the  concave  side  will  point  to  the  hand  to  which  it 
belongs. 

Articulations. — With  the  cuneiform  bone  only. 

Attachments. — To  two  muscles  —  the  flexor  carpi  ulnaris,  and 
abductor  minimi  digiti ;  and  to  the  annular  ligament. 

The  trapezium  is  too  irregular  in  form  to  be  compared  to  any 
known  object ;  it  may  be  distinguished  by  a  deep  groove  for  the 
tendon  of  ihe  flexor  carpi  radialis  muscle.  It  is  sornewhat  com- 
pressed, and  may  be  divided  into  two  surfaces  which  are  smooth 
and  articular,  and  three  rough  borders.  One  of  the  articular  sur- 
faces is  nval,  concave  in  one  direction,  and  convex  in  the  other ; 
the  other  is  marked  into  three  facets.  One  of  the  borders  presents 
the  groove  for  the  tendon  of  the  flexor  carpi  radialis,  which  is 
surmounted  by  a  prominent  tubercle  for  the  attachment  of  the  annular 
ligament ;  the  other  two  borders  are  rough  and  form  the  outer  side 
of  the  carpus.  The  grooved  border  is  narrow  at  one  extremity 
and  broad  at  the  other,  where  it  presents  the  groove  and  tubercle. 

U  the  bone  be  held  so  that  the  grooved  border  look  upwards 
while  the  apex  of  this  border  be  directed  forwards,  and  the  base 
with  the  tubercle  backwards,  the  concavo-convex  surface  will 
point  to  the  hand  to  which  the  bone  belongs. 

Articulations. — W\i\\  four  bones  ;  by  the  concavo-convex  surface, 
with  the  metacarpal  bone  of  the  thumb ;  and  by  the  three  facets  of 
the  other  articular  surface,  with  the  scaphoid,  trapezoid,  and  second 
metacarpal  bone. 

Attachments. — To  two  muscles — flexor  ossis  metacarpi,  and  flexor 
brevis  pollicis  ;  and  by  the  tubercle,  to  the  annular  ligament. 

The  trapezoides  is  a  small,  oblong,  and  quadrilateral  bone,  bent 


OS  MAGNUM UNCIFORME.  103 

near  its  middle  upon  itself.  It  presents  four  articular  surfaces  and 
two  extremities.  One  of  the  surfaces  is  concavo-convex, — /.  e.  con- 
cave in  one  direction  and  convex  in  the  other ;  another,  contiguous 
to  the  preceding,  is  concave,  so  as  to  be  almost  angular  in  the 
middle,  and  is  often  marked  by  a  small  rough  depression,  for  an 
interosseous  ligament ;  the  two  remaining  sides  are  Jlat,  and  present 
nothing  remarkable.  One  of  the  two  extremities  is  broad  and  of 
large  size, — the  dorsal;  the  other,  or  j)almar,  is  small  and  rough. 

If  the  bone  be  held  perpendicularly,  so  that  the  broad  extremity 
be  upwards,  and  the  concavo-convex  surface  forwards,  the  angular 
concave  surface  will  point  to  the  hand  to  which  the  bone  belongs. 

Articulations. — With  four  bones  ;  by  the  concavo-convex  surface 
with  the  second  metacarpal  bone;  by  the  angular  concave  surface 
with  the  OS  magnum  ;  and  by  the  other  two  surfaces,  with  the  trape- 
zium and  scaphoid. 

Attachments. — To  the  flexor  brevis  pollicis  muscle. 

The  OS  magnum  is  the  largest  bone  of  the  carpus,  and  is  divisible 
into  a  body  and  head.  The  head  is  round  for  the  greater  part  of 
its  extent,  but  is  flattened  on  one  side.  The  body  is  irregularly 
quadrilateral,  and  pi^esents  four  sides  and  a  smooth  extremity.  Two 
of  the  sides  are  rough,  the  one  being  square  and  flat  —  the  dorsal, 
the  other  rounded  and  prominent — the  palmar;  the  other  two  sides 
are  articular,  the  one  being  concave,  the  other  convex.  The 
extremity  is  a  triangular  articular  surface,  divided  into  three  facets. 

If  the  bone  be  held  perpendicularly,  so  that  the  articular  extremity 
look  upwards  and  the  broad  dorsal  surface  backwards  (towards  the 
holder),  the  concave  articular  surface  will  point  to  the  hand  to  which 
the  bone  belongs. 

Articulations. — With  seven  bones;  by  the  rounded  head,  with  the 
cup  formed  by  the  scaphoid  and  semilunar  bone ;  by  the  side  of  the 
convex  surface,  with  the  trapezoides ;  by  the  concave  surface,  with 
the  unciforme ;  and  by  the  extremity,  with  the  second,  third,  and 
fourth  metacarpal  bones. 

Attachments. — To  the  flexor  brevis  pollicis  muscle. 

The  unciforme  is  a  triangular-shaped  bone,  remarkable  for  a  long 
and  curved  process,  which  projects  from  its  palmar  aspect.  It  pre- 
sents five  surfaces; — three  articular,  and  two  free.  One  of  the 
articular  surfaces  is  divided  by  a  slight  ridge  into  two  facets;  the 
other  two  converge,  and  meet  at  a  flattened  angle.*  One  of  the 
free  surfaces — the  dorsal — is  rough  and  triangular  ;  the  other — 
palmar,  also  triangular,  but  somewhat  smaller,  gives  origin  to  the 
unciform  process. 

If  the  bone  be  held  perpendicularly,  so  that  the  articular  surface 
with  two  facets  look  upwards,  and  the  unciform  process  back- 
wards (towards  the  holder),  the  concavity  of  the  unciform  process 
will  point  to  the  hand  to  which  the  bone  belongs. 

Articulations. — With  ^t;e  bones ;  by  the  two  facets  on  its  base, 

*  When  the  unciforme  does  not  articulate  witli  the  semilunare,  this  angle  is  sharp. 


104 


METACARPUS. 


with  the  fourth  and  fifth  metacarpal  bones ;  by  the  two  lateral  arti- 
culating surfaces,  with  the  magnum  and  cuneiforme ;  and  by  the 
flattened  angle  of  its  apex,  witfi  the  semilunare. 

Attachnients. — To  two  muscles — the  adductor  minimi  digiti,  and 
flexor  brevis  minimi  digiti ;  and  to  the  annular  ligament. 

Developement. — The  bones  of  the  carpus  are  each  developed  by 
a  single  centre. 

The  number  of  articulations  which  each  bone  of  the  carpus  pre- 
sents with  surrounding  bones,  may  be  expressed  in  figures,  which 
will  materially  facilitate  their  recollection;  the  number  for  the  first 
row  is  5531,  and  for  the  second  4475. 

Metacarpus. — The  bones  of  the  metacarpus  are  five  in  number. 
They  are  long  bones,  divisible  into  a  head,  shaft,  and  base. 

The  head  is  rounded  at  the  extremity,  and  flattened  at  each  side, 
for  the  insertion  of  strong  ligaments ;  the  shaft  is  prismoid,  and 
marked  deeply  on  each  side,  for  the  attachment  of  the  interossei 
muscles;  and  the  base  is  irregularly  quadrilateral  and  rough,  for 
the  insertion  of  tendons  and  ligaments.  The  base  presents  three 
articular  surfaces,  one  at  each  side,  for  the  adjoining  metacarpal 

bones ;  and  one  at  the  extremity  for  the 
carpus. 

The  metacarpal  bone  of  the  thumb  is 
one-third  shorter  than  the  rest,  flattened 
and  broad  on  its  dorsal  aspect,  and  convex 
on  its  palmar  side ;  the  articular  surface 
of  the  head  is  not  so  round  as  that  of  the 
other  metacarpal  bones  ;  and  the  base  has 
a  single  concavo-convex  surface,  to  arti- 
culate with  the  similar  surface  of  the  tra- 


Fig.  38. 


pezmm. 

The  metacarpal  bones  of  the  different 
fingers  may  be  distinguished  by  certain 
obvious  characters.  The  base  of  the 
metacarpal  bone  of  the  index  finger  is  the 
largest  of  the  four,  and  presents  four  arti- 
cular surfaces.  That  of  the  middle  finger 
may  be  distinguished  by  a  rounded  pro- 
jecting process  upon  the  radial  side  of  its 
base,  and  two  small  circular  facets  upon 
its  ulnar  lateral  surface.  The  base  of  the  metacarpal  bone  of  the 
ring-finger  is  small  and  square,  and  has  two  small  circular  facets  to 
correspond  with  those  of  the  middle  metacarpal.  The  metacarpal 
bone  of  the  little  finger  has  only  one  lateral  articular  surface. 

Fig.  38.  Tlic  hand  viewed  upon  its  anterior  or  palmar  aspect.    1.  The  scaphoid  bone, 
2.   The    scinilunare.     3.    The    cuneiforme.     4.    The    pisiforme.     .5.    The    trapezium. 

6.  The  groove   in   the  trapezium  that  iodgca  the   tendon  of  the  flexor  carpi   radialis. 

7.  The  trapczoides.  8.  The  os  magnutn.  9.  The  uneiforme.  10,  10.  The  five  mcta- 
carpal  bone.s.  11,  11.  The  first  row  of  phalanges.  13,  12.  The  .second  row.  13,  13. 
The  third  row,  or  ungual  phalanges.  14.  The  first  phalanx  of  the  thumb,  l.").  The 
second  and  last  phalanx  of  the  tiiumb. 


METACARPUS PHALANGES.  105 

Developement. — By  Uw  centres  ;  one  for  the  shaft,  and  one  for  the 
digital  extremity. 

Articulations.— The  first  with  the  trapezium  ;  second,  with  the 
trapezium,  trapezoides,  and  os  magnum,  and  with  the  middle  meta- 
carpal bone ;  third,  or  middle,  with  the  os  magnum,  and  adjoining 
metacarpal  bones;  fourth,  v.^ith  the  os  magnum  and  unciforme, and 
with  the  adjoining  metacarpal  bones ;  and  fifth,  with  the  unciforme, 
and  with  the  metacarpal  bone  of  the  ring-finger. 

The  figures  resulting  from  the  number  of  articulations  which  each 
metacarpal  bone  possesses,  taken  from  the  radial  to  the  ulnar  side, 
are  13121. 

Attachment  of  Muscles. — To  the  metacarpal  bone  of  the  thumb, 
three — the  flexor  ossis  metacarpi,  extensor  ossis  metacarpi  and  first 
dorsal  interosseous ;  of  the  index  finger,  five — the  extensor  carpi 
radialis  longior,  flexor  carpi  radialis,  first  and  second  dorsal  interos- 
seous, and  first  palmar  interosseous  ;  of  the  middle  finger,  fout^ — 
the  extensor  carpi  radialis  brevior,  adductor  pollicis,  and  second 
and  third  dorsal  interosseous ;  of  the  ring-finger,  three — the  third 
and  fourth  dorsal  interosseous,  and  second  palmar  ;  and  of  the  little 
finger,  four — extensor  carpi  ulnaris,  adductor  minimi  digiti,  fourth 
dorsal  and  third  palmar  interosseous. 

Phalanges. — The  phalanges  are  the  bones  of  the  fingers  ;  they 
are  named  from  their  arrangement  in  rows,  and  are  fourteen  in 
number, — -three  to  each  finger,  and  two  to  the  thumb.  In  confor- 
mation they  are  long  bones,  divisible  into  a  shaft,  and  two  extre- 
mities. 

The  shaft  is  compressed  from  before  backwards  convex  on  its 
posterior  surface,  and  flat  with  raised  edges  in  front.  The  meta- 
carpal extremity  of  the  first  row  is  a  simple  concave  articular  surface 
— of  the  other  two  rows  a  double  concavity,  separated  by  a  slight 
ridge.  The  digital  extremities  of  the  first  and  second  row  present 
a  pulley-like  surface,  concave  in  the  middle,  and  convex  on  each 
side.  The  unguial  extremity  of  the  last  phalanx  is  broad,  rough 
and  expanded  into  a  semilunar  crest. 

Deveh'pement. — By  two  centres ;  one  for  the  shaft,  and  one  for 
the  metacarpal  extremity. 

Articulations. — The  first  row,  with  the  metacarpal  bones  and 
second  row  of  phalanges;  the  second  row,  with  the  first  and  third  ; 
and  the  third,  with  the  second  row. 

Attachment  of  Muscles. — To  the  base  of  ihe  first  phalanx  of  the 
thumb  four  muscles — abductor  pollicis,  flexor  brevis  pollicis,  ad- 
ductor pollicis,  and  extensor  primi  internodii ;  and  to  the  second 
phalanx  two — the  flexor  longus  pollicis,  and  extensor  secundi  in- 
ternodii. To  the  first  phalanx  of  the  second,  third,  and  fourth 
fingers,  one  dorsal  and  one  palmar  interosseous,  and  to  the  first 
phalanx  of  the  little  finger,  the  abductor  minimi  digiti,  flexor  brevis 
minimi  digiti,  and  one  palmar  interosseous.  To  the  second  phalanges 
the  flexor  sublimis  and  extensor  communis  digitorum ;  and  to  the 


106  PELVIS. 

last  phalanges — the  flexor  profundus  and  extensor  communis  digi- 
torum. 

PELVIS     AND     LOWER     EXTREMITY. 


Fiff.  39. 


The  bones  of  the  pelvis  are  the  two  ossa  innominata,  the  sacrum, 
and  the  coccyx;  and  of  the  lower  extremity,  the  femur,  patella,  tibia 
and  fibula,  tarsus,  metatarsus,  and  phalanges. 

Os  LvNOMiivATUM. — The  OS  innominatum  is  an  irregular  flat  bone, 
consisting  in  the  young  subject  of  three  parts,  which  meet  at  the 
acetabulum.  Hence  it  is  usually  described  in  the  adult  as  divisible 
into  three  portions, — ilium,  ischium,  and  pubis.  The  ilium  is  the 
superior  broad  and  expanded  portion  which  forms  the  prominence 
of  the  hip,  and  articulates  with  the  sacrum.  The  ischium  is  the 
inferior  and  strong  part  of  the  bone  on  which  we  sit.  The  fubis  is 
that  portion  which  forms  the  front  of  the  pelvis,  and  gives  support 
to  the  external  organs  of  generation. 

The  ilium  may  be  described  as  divisible  into  an  internal  and  ex- 
ternal surface,  a  crest,  and  an  anterior  and  posterior  border. 

The  internal  surface  is  bounded  above  by  the  crest,  below  by  a 
prominent  line — the  linea  ilio-pectinea,  and  before  and  behind  by 

the  anterior  and  posterior  bor- 
ders ;  it  is  concave  and  smooth 
for  the  anterior  two-thirds  of  its 
extent,  and  lodges  the  iliacus 
muscle.  The  posterior  third  is 
rough,  for  articulation  with  the 
sacrum,  and  is  divided  into  two 
parts  by  a  deep  groove ; — an 
anterior  or  auricular  portion, 
which  is  shay^ed  like  the  pinna, 
and  coated  by  cartilage  in  the 
fresh  bone ;  and  a  posterior 
portion,  which  is  very  rough, 
for  the  attachment  of  interos- 
seous ligaments. 

The  external  surface  is 
rough,  partly  convex,  and 
partly  concave ;  it  is  bounded 
above  by  the  crest;  below,  by 
a  prominent  arch,  which  forms 

Fig'.  39.  The  os' innominatum  of  the  riirht  side.  1.  The  ilium  ;  its  external  surface, 
2.  The  ischium.  3.  Tlic  os  pubis.  4.  The  crest  of  the  ilium,  5.  The  superior  curved 
line.  6.  'I'he  inferior  curved  line.  7.  The  surface  for  the  gluteus  maximus.  8.  The 
anterior  superior  spinous  process.  9.  The  anterior  inferior  spinous  process.  10.  The 
posterior  superior  spinous  process.  11.  The  posterior  inferior  spinous  process.  12. 
The  spine  of  the  iscliium.  13.  Tiie  great  saero-ischiaiic  notch.  14.  The  lesser  sacro- 
ischiatic  notch.  15.  The  tuberosity  of  the  ischium,  showing  its  three  facets.  16. 
The  ramus  of  the  ischium.  17.  The  body  of  the  os  pubis.  18.  The  ramus  of  the 
pubis.    19.  The  acetabulum.    20.  The  foramen  thyroideum. 


ISCHIUM  —  OS  PUBIS.  107 

the  upper  segment  of  the  acetabulum ;  and  before  and  behind 
by  the  anterior  and  posterior  borders.  Crossing  this  surface  in  an 
arched  direction,  from  the  anterior  extremity  of  the  crest  to  a  notch 
upon  the  lower  part  of  the  posterior  border,  is  a  groove,  which 
lodges  the  gluteal  vessels  and  nerve — the  superior  curved  line  ;  and 
below  this,  at  a  short  distance,  a  rough  ridge, — the  inferior  curved 
line.  The  surface  included  between  the  superior  curved  line  and 
the  crest,  gives  origin  to  the  gluteus  medius  muscle ;  that  between 
the  curved  lines,  to  the  gluteus  minimus ;  and  the  rough  interval 
between  the  inferior  curved  line  and  the  arch  of  the  acetabulum,  to 
one  head  of  the  rectus.  The  posterior  sixth  of  this  surface  is  rough 
and  raised,  and  gives  origin  to  part  of  the  gluteus  maximus. 

The  crest  of  the  ilium  is  arched  and  sigmoid  in  its  direction,  being 
bent  inwards  at  its  anterior  termination,  and  outwards  towards  the 
posterior.  It  is  broad  for  the  attachment  of  three  planes  of  muscles, 
which  are  connected  with  its  external  and  internal  borders  or  lips, 
and  with  the  intermediate  space. 

The  anterior  border  is  marked  by  two  projections, — the  anterior 
superior  spinous  process,  which  is  the  anterior  termination  of  the 
crest,  and  the  anterior  inferior  spinous  process ;  the  two  processes 
being  separated  by  a  notch  for  the  attachment  of  the  sartorius 
muscle.  This  border  terminates  inferiorly  in  the  lip  of  the  aceta- 
bulum. The  posterior  border  also  presents  two  projections, — the  pos- 
terior superior  and  the  posterior  inferior  spinous  process, — separated 
by  a  notch.  Inferiorly  this  border  is  broad  and  arched,  and  forms 
the  upper  part  of  the  great  sacro-ischiatic  notch. 

The  ischium  is  divisible  into  a  thick  and  solid  portion — the  body, 
and  into  a  thin  and  ascending  part — the  ramus ;  it  may  be  consi- 
dered also,  for  convenience  of  description,  as  presenting  an  external 
and  internal  surface,  and  three  borders, — posterior,  inferior,  and 
superior. 

The  external  suiface  is  rough, for  the  attachment  of  muscles  ;  and 
broad  and  smooth  above,  where  it  enters  into  the  formation  of  the 
acetabulum.  Below  the  inferior  lip  of  the  acetabulum  is  a  notch, 
which  lodges  the  obturator  externus  muscle  in  its  passage  outwards 
to  the  trochanteric  fossa  of  the  femur.  The  internal  surface  is 
smooth,  and  somewhat  encroached  upon  at  its  posterior  border  by 
the  spine. 

The  posterior  border  of  the  ischium  presents  towards  its  middle  a 
remarkable  projection, — the  spine.  Immediately  above  the  spine  is 
a  notch  of  large  size — the  great  sacro-ischiatic,  and  below  the  spine 
the  lesser  sacro-ischiatic  notch  ;  the  former  being  converted  into  a 
foramen  by  the  lesser  sacro-ischiatic  ligament,  gives  passage  to  the 
pyriformis  muscle,  and  to  the  gluteal  vessels  and  nerve,  pudic  vessels 
and  nerve,  and  ischiatic  vessels  and  nerves ;  and  the  lesser  com- 
pleted by  the  great  sacro-ischiatic  ligament,  to  the  obturator  internus 
muscle,  and  to  the  internal  pudic  vessels  and  nerve.  The  inferior 
border  is  thick  and  broad,  and  is  called  the  tuberosity.  The  surface 
of  the  tuberosity  is  divided  into  three  facets ;  one  anterior,  which  is 


108  ACETABULUM OBTURATOR  FORAMEN. 

rough  for  the  origin  of  the  semi-membranosus ;  and  two  posterior, 
which  are  smooth,  and  separated  by  a  sUght  ridge  for  the  semi-ten- 
dinosus  and  biceps  muscles.  The  inner  margin  of  the  tuberosity  is 
bounded  by  a  sharp  ridge,  which  gives  attachment  to  a  prolongation 
of  the  great  sacro-ischiatic  hgament.  The  superior  border  of  the 
ischium  is  thin,  and  forms  the  lower  circumference  of  the  obturator 
foramen.  The  ramus  of  the  ischium  is  continuous  with  the  ramus 
of  the  pubis,  and  is  slightly  everted. 

The  pubis  is  divided  into  a  horizontal  portion  or  body,  and  a  de- 
scending portion  or  ramus;  it  presents  for  examination  an  external 
and  internal  surface,  a  superior  and  inferior  border,  and  symphysis. 

The  external  surface  is  rough,  for  the  attachment  of  muscles  ;  and 
prominent  at  its  outer  extremity,  where  it  forms  part  of  the  acetabu- 
lum. The  internal  surface  is  smooth.  The  superior  border  is  marked 
by  a  rough  ridge — the  crest ;  the  inner  termination  of  the  crest  is  the 
angle ;  and  the  outer  end,  the  spine  or  tuberosity.  Running  out- 
wards from  the  spine  is  a  sharp  ridge,  the  pectineal  line — or  linea 
ilio-pectinea,  which  marks  the  brim  of  the  true  pelvis.  In  front  of 
the  pectineal  line  is  a  smooth  depression,  which  supports  the  femoral 
vein,  and  a  little  more  externally  an  elevated  prominence,  the  pec- 
tineal eminence,  which  divides  the  surface  for  the  vein  from  another 
depression  which  overhangs  the  acetabulum,  and  lodges  the  psoas 
and  iliacus  muscles.  The  inferior  border  is  broad  and  deeply 
grooved,  for  the  passage  of  the  obturator  vessels  and  nerve  ;  and 
sharp  upon  the  side  of  the  ramus,  to  form  part  of  the  boundary  of 
the  obturator  foramen.  The  symphysis  is  the  inner  extremity  of  the 
body  of  the  bone  ;  it  is  oval  and  rough,  for  the  attachment  of  a  liga- 
mentous structure  analogous  to  the  intervertebral  substance.  The 
ramus  of  the  pubis  descends,  and  is  continuous  with  the  ramus  of 
the  ischium.  Its  inner  border  is  considerably  everted,  to  afibrd  a 
strong  attachment  to  the  crus  penis. 

The  acetabulum  is  a  deep  cup-shaped  cavity,  situated  at  the  point 
of  union  between  the  ilium,  ischium,  and  pubis;  a  little  less  than 
two-fifths  being  formed  by  the  ilium,  a  little  more  than  two-fifths 
by  the  ischium,  and  the  remaining  fifth  by  the  pubis.  It  is  bounded 
by  a  deep  rim  or  lip,  which  is  broad  and  strong  above,  where  most 
resistance  is  required,  and  marked  in  front  by  a  deep  notch,  which 
transmits  the  nutrient  vessels  into  the  joint.  At  the  bottom  of  the 
cup,  and  communicating  with  the  notch,  is  a  deep  and  circular  pit, 
which  lodges  a  mass  of  fat,  and  gives  attachment  to  the  broad  ex- 
tremity of  the  ligamentum  teres. 

The  obturator  or  thyroid  foramen  is  a  large  oval  interval  between 
the  ischium  and  pubis,  bounded  by  a  narrow  rough  margin,  to  which 
a  ligamentous  membrane  is  attached.  The  upper  part  of  the  fora- 
men is  increased  in  depth  by  the  groove  in  the  under  surface  of  the 
OS  pubis,  which  lodges  the  obturator  vessels  and  nerve. 

Developement. — By  eight  centres;  three  principal — one  for  the 
ilium,  one  for  the  ischium,  and  one  for  the  pubis  ;  and  five  secondary 
— one  for  the  crest  of  the  ilium,  and  one  for  its  anterior  inferior 


PELVIS.  109 

spinous  process,  one  for  the  centre  of  the  acetabulum,  one  for  the 
tuberosity  of  the  ischium,  and  one  (not  constant)  for  the  angle  of 
the  pubis. 

Articulations. — With  three  bones  ;  sacrum,  opposite  innominatum, 
and  femur. 

Attachment  of  Muscles  and  Ligaments. — To  thirty -Jive  muscles; 
to  the  ilium,  thirteen  ;  by  the  outer  lip  of  the  crest,  to  the  obliquus 
externus  for  two-thirds,  and  to  the  latissimus  dorsi  for  one-third  its 
length,  and  to  the  tensor  vaginae  femoris  by  its  anterior  fourth ;  by 
the  middle  of  the  crest,  to  the  internal  oblique  for  three-fourths  its 
length,  by  the  remaining  fourth  to  the  erector  spinse  ;  by  the  inter- 
nal lip,  to  the  transversalis  for  three-fourths,  and  to  the  quadratus 
lumborum  by  the  posterior  part  of  its  middle  third.  By  the  external 
surface,  to  the  gluteus  medius,  minimus  and  maximus,  and  to  one 
head  of  the  rectus ;  by  the  internal  surface,  to  the  iliacus ;  and  by 
the  anterior  border,  to  the  sartorius,  and  the  other  head  of  the  rectus. 
To  the  ischium  sixteen ;  by  its  external  surface,  the  adductor  mag- 
nus  and  obturator  externus  ;  by  the  internal  surface,  the  obturator 
internus  and  levator  ani ;  by  the  spine,  the  gemellus  superior,  levator 
ani,  coccygeus,  and  lesser  sacro-ischiatic  ligament ;  by  the  tubero- 
sity, the  biceps,  semi-tendinosus,  semi-membranosus,  gemellus  infe- 
rior, quadratus  femoris,  erector  penis,  transversus  perinei,  and  great 
sacro-ischiatic  ligament  ;  and  by  the  ramus,  the  gracilis,  accelera- 
tor urinae,  and  compressor  urethrse.  To  the  pubis  fifteen ;  by  its 
upper  border,  the  obliquus  externus,  obliquus  internus,  transver- 
salis, rectus,  pyramidalis,  pectineus,  and  psoas  parvus ;  by  its  ex- 
ternal surface,  the  adductor  longus,  adductor  brevis  and  gracilis ; 
by  its  internal  surface,  the  levator  ani,  compressor  urethrse,  and 
obturator  internus ;  and  by  the  ramus,  the  adductor  magnus,  and 
accelerator  urinae. 

PELVIS. 

The  pelvis  considered  as  a  whole  is  divisible  into  a  false  and  true 
pelvis ;  the  former  is  the  expanded  portion,  bounded  on  each  side  by 
the  ossa  ilii,  and  separated  from  the  true  pelvis  by  the  linea  ilio- 
pectinea.  The  true  pelvis  is  all  that  portion  which  is  situated  be- 
neath the  linea  ilio-pectinea.  This  line  forms  the  margin  or  brim  of 
the  true  pelvis,  while  the  included  area  is  called  the  inlet.  The  form 
of  the  inlet  is  heart-shaped,  obtusely  pointed  in  front  at  the  symphy- 
sis pubis,  expanded  on  each  side,  and  encroached  upon  behind  by  a 
projection  of  the  upper  part  of  the  sacrum,  which  is  named  the  pro- 
montory. The  cavity  is  somewhat  encroached  upon  at  each  side 
by  a  smooth  quadrangular  plane  of  bone,  corresponding  with  the 
internal  surface  of  the  acetabulum,  and  leading  to  the  spine  of  the 
ischium.  In  front  are  two  fossie  around  the  obturator  foramina,  for 
lodging  the  obturator  internus  muscle,  at  each  side.  The  inferior 
termination  of  the  pelvis  is  very  irregular,  and  is  termed  the  outlet. 
It  is  bounded  in  front  by  the  convergence  of  the  rami  of  the  ischium 

10 


110  PELVIS. 

and  pubis,  which  constitute  the  arch  of  the  pubis ;  on  each  side  by 
ihe  tuberosity  of  the  ischium,  and  by  two  irregular  fissures  formed 
by  the  greater  and  lesser  sacro-ischiatic  notches  ;  and  behind  by  the 
inferior  borders  of  the  sacrum,  and  by  the  coccyx. 

The  pelvis  is  placed  obliquely  with' regard  to  the  trunk  of  the  body, 
so  that  a  line  drawn  through  the  central  axis  of  the  inlet,  would  touch 
by  one  extremity  the  lower  part  of  the  sacrum,  and  by  the  other 
would  pass  through  the  umbilicus.  The  axis  of  the  inlet  is  therefore 
directed  downwards  and  backwards,  while  that  of  the  outlet  points 
doionwards  and.  forwards,  and  corresponds  with  a  line  drawn  from 
the  upper  part  of  the  sacrum,  through  the  centre  of  the  outlet.  The 
axis  of  the  cavity  represents  a  curve,  the  extremities  of  which  will 
be  indicated  by  the  central  points  of  the  inlet  and  outlet.  A  know- 
ledge of  the  direction  of  these  axes  is  most  important  to  the  surgeon, 
as  indicating  the  line  in  which  instruments  should  be  used  in  opera- 
tions upon  the  viscera  of  the  pelvis,  and  the  direction  of  force  in  the 
removal  of  calculi  from  the  bladder  ;  and  to  the  accoucheur,  as  ex- 
plaining the  course  of  the  foetus  during  parturition. 

There  are  certain  striking  differences  between  the  male  and 
female  pelvis.  In  the  male  the  bones  are  thicker,  stronger,  and 
more  solid,  and  the  cavity  deeper  and  narrower.  In  the  female  the 
bones  are  lighter  and  more  delicate,  the  iliac  fossae  are  large  and 
the  ilia  projecting ;  the  inlet,  and  the  outlet,  and  the  cavity  are 
large,  and  the  acetabula  farther  removed  from  each  other;  the 
cavity  is  shallow,  the  tuberosities  widely  separated — the  obturator 
foramina  triangular,  and  the  arch  of  the  pubis  wide.  The  precise 
diameter  of  the  inlet  and  outlet,  and  the  depth  of  the  cavity,  are 
very  important  considerations  to  the  accoucheur. 

The  diameters*  of  the  inlet  or  brim  are  three: — 1.  Antero-pos- 
terior,  sacro-pubic  or  conjugate ;  2,  transverse ;  and  3,  oblique. 
The  antero-posterior  extends  from  the  symphysis  pubis  to  the  middle 
of  the  promontory  of  the  sacrum,  and  measures  four  inches  and  a 
half.  The  transverse  extends  from  the  middle  of  the  brim  on  one 
side  to  the  same  point  on  the  opposite,  and  measures  five  inches  and 
a  quarter.  The  oblique  extends  from  the  sacro-iliac  symphysis  on 
one  side,  to  the  margin  of  the  brim  corresponding  with  the  aceta- 
bulum on  the  opposite,  and  measures  five  inches  and  one-eighth. 

The  diameters  of  the  outlet  are  two,  antero-posterior,  and  trans- 
verse. The  antero-posterior  diameter  extends  from  the  lower  part 
of  the  symphysis  pubis,  to  the  apex  of  the  coccyx ;  and  the  trans- 
verse from  the  first  part  of  one  tuberosity  to  the  same  point  on  the 
opposite  side;  they  both  measure  four  inches.  The  cavity  of  the 
pelvis  measures  in  depth  four  inches  and  a  half,  posteriori}^;  three 
inches  and  a  half  in  the  middle ;  and  one  and  a  half  at  the  sym- 
physis pubis. 

Femur. — The  femur  is  a  long  bone,  divisible,  like  other  bones  of 
the  same  class,  into  a  shaft,  a  superior  and  an  inferior  extremity. 

*  Tlicac  diameters  are  quoted  from  an  excellent  "Manual  of  Practical  Midwifery," 
by  Dr.  James  lleid. 


FEMUR. 


Ill 


At  the  superior  extremity  is  a  rounded  head,  directed  upwards  and 
inwards,  and  marked  just  below  its  centre  by  an  oval  depression  for 
the  ligamentum  teres.  The  head  is  supported  by  a  neck,  which 
varies  in  length  and  obliquity  at  various  periods  of  life,  being  long 
and  oblique  in  the  adult— short  and  almost  horizontal  in  the  aged. 
Externally  to  the  neck  is  a  large  process,— the  trochanter  major, 
which  presents  upon  its  anterior  surface  an  oval 
facet,  for  the  attachment  of  the  tendon  of  the  glu-  Fig.  40, 

teus  minimus  muscle;  and  above,  a  double  facet, 
for   the  insertion  of  the  gluteus  medius.     On  its 
posterior  side  is  a  vertical  ridge — the  linea  quad-     ^.™,^,     ,  m 
rati,  for  the  attachment  of  the  quadratus  femoris      ^M^^'"/^* 
muscle.     Upon  the  inner  side  of  the  trochanter      ^«™y^>^ 
major  is  a  deep  ^ai,  trochanteric  or  digital  fossa,        iiii|]i|'4^ 
in  which  are  inserted  the  tendons  of  the  pyrifor- 
mis,  gemellus  superior  and  inferior,  and  obturator 
externus  and  internus  muscles.  Passing  downwards 
from  the  trochanter  major  in  front  of  the  bone  is 
an  oblique  ridge,  which  forms  the  inferior  boun- 
dary of  the  neck, — the  anterior  intertrochanteric 
line ;  and  behind,  another  oblique  ridge,  the  poste- 
rior intertrochanteric  line,  which  terminates  in  a 
rounded  tubercle  upon  the  posterior  and  inner  side 
of  the  bone,  the  trochanter  minor. 

The  shaft  of  the  femur  is  convex  and  rounded  in 
front,  and  covered  with  muscles;  and  somewhat 
concave  and  raised  into  a  rough  and  prominent 
ridge  behind,  the  linea  aspera.  The  linea  aspera 
near  the  upper  extremity  of  the  bone  divides  into 
three  branches.  The  anterior  branch  is  continued 
forwards  in  front  of  the  lesser  trochanter,  and  is 
continuous  with  the  anterior  intertrochanteric  line ; 
the  middle  is  continued  directly  upwards  into  the 
linea  quadrati ;  and  the  posterior,  broad  and 
strongly  marked,  ascends  to  the  base  of  the  trochanter  major. 
Towards  the  lower  extremity  of  the  bone  the  linea  aspera  divides 
into  two  ridges,  which  descend  to  the  two  condyles,  and  enclose  a 
triangular  space  upon  which  rests  the  popliteal  artery.  The  in- 
ternal condyloid  ridge  is  less  marked  than  the  external,  and 
piresents  a  broad  and  shallow  groove,  for  the  passage  of  the  femoral 
artery.  The  nutritious  foramen  is  situated  in  or  near  the  linea 
aspera,  at  about  one-third  from  its  upper  extremity,  and  is  directed 
obliquely  from  below-  upwards. 

Fitr.  40.  The  right  femur,  seen  upon  the  anterior  aspect.  1,  The  shaft.  2.  The 
headr  3.  The  neck.  4.  The  great  trochanter.  5.  The  anterior  intertrochanteric  line. 
6.  The  lesser  trochanter.  7.  The  external  condyle.  8.  The  interna!  condyle.  9.  The 
tuberosity  for  the  attachment  of  the  external  lateral  ligaments.  10.  The  groove  for  the 
tendon  of  origin  of  the  popliteus  muscle.  11.  The  tuberosity  for  the  attachment  of  the 
internal  lateral  ligament. 


112 


m 


The  loicer  extremity  of  the  femur  is  broad  and  porous,  and  divided 
by  a  smooth  depression  in  front,  and  by  a  considerable  notch 
behind,  into  two  condyles. 

The  external  condyle  is  the  broadest  and  most  projecting,  and  the 
internal  the  narrowest  and  longest ;  the  difference  in  length  depend- 
ing upon  the  obliquity  of  the  femur,  in  consequence  of  the  separa- 
tion of  the  two  bones  at  their  upper  extremities  by  the  breadth  of 
the  pelvis.  The  external  condyle  is  marked  upon  its  outer  side  by 
a  prominent  tuberosity,  which  gives  attachment  to  the  external 
lateral  ligaments ;  and  immediately  beneath  this  is  the  groove  which 
lodges  the  tendinous  origin  of  the  popliteus.  By  the  internal  sur- 
face it  gives  attachment  to  the  anterior  crucial  ligament  of  the 
knee-joint ;  and  by  its  upper  and  posterior  part,  to  the  external  head 
of  the  gastrocnemius  and  to  the  plantaris.  The 
Fig.  41.  internal  condyle  projects  upon  its  inner  side  into  a 

tuberosity,  to  which  is  attached  the  internal  lateral 
ligament ;  above  this  tuberosity,  at  the  extremity 
of  the  internal  condyloid  ridge,  is  a  tubercle,  for 
the  insertion  of  the  tendon  of  the  adductor  magnus ; 
and  beneath  the  tubercle,  upon  the  upper  surface  of 
the  condyle,  a  depression,  from  which  the  internal 
head  of  the  gastrocnemius  arises.  The  outer  side 
of  the  internal  condyle  is  rough  and  concave,  for 
the  attachment  of  the  posterior  crucial  ligament. 

Developement. — By  Jive  centres ;  one  for  the 
shaft,  one  for  each  extremity,  and  one  for  each 
trochanter. 

Articulations. — With  three  bones ;  with  the  os 
innominatum,  tibia,  and  patella. 

Attachment  of  Muscles. — To  twenty-three ;  by  the 
greater  trochanter,  to  the  gluteus  medius  and  mini- 
mus, pyriformis,  gemellus  superior,  obturator  in- 
ternus,  gemellus  inferior,  obturator  externus,  and 
quadratus  femoris ;  by  the  lesser  trochanter,  to  the 
common  tendon  of  the  psoas  and  iliacus.  By  the 
linea  aspera,  its  outer  lip,  to  the  vastus  externus, 
gluteus  maximus,  and  short  head  of  the  biceps  ;  by 
its  inner  lip,  to  the  vastus  internus,  pectineus,  ad- 
ductor brevis,  and  adductor  longus;  by  its  middle 
to  the  adductor  magnus ;  by  the  anterior  part  of 
the  bone,  to  the  crurseus  and  subcrurrous ;  by  its 
condyles,  to  the  gastrocnemius,  plantaris  and  popliteus. 


ahU 


Fig.  41.  A  diagram  of  the  posterior  aspect  of  the  right  femur,  showing  the  lines  of 
attachment  of  the  muscles.  The  muscles  attached  to  the  inner  lip  are, — p,  the  pecti- 
neus ;  a  h,  the  adductor  brevis ;  and  a  I,  the  adductor  longus.  The  middle  portion  is 
occupied  for  its  whole  extent  by  a  m,  the  adductor  magnus  ;  and  is  continuous  supe- 
riorly with  q  f,  the  linea  quadrati,  into  which  the  quadratus  femoris  is  inserted.  The 
outer  lip  is  occupied  by  g  m,  tlie  gluteus  maximus ;  and  6,  the  short  head  of  the 
biceps. 


PATELLA TIBIA. 


113 


M' 


Patella. — The  patella  is  a  sesamoid  bone,  developed  in  the  ten- 
don of  the  quadriceps  extensor  muscle,  and  usually  described  as  a 
bone  of  the  lower  extremity.  It  is  heart-shaped  in  figure,  the  broad 
side  being  directed  upwards  and  the  apex  downwards,  the  external 
surface  convex,  and  the  internal  divided  by  a  ridge  into  two  smooth 
surfaces,  to  articulate  with  the  condyles  of  the  femur.  The  exter- 
nal articular  surface  corresponding  with  the  external  condyle  is  the 
larger  of  the  two,  and  serves  to  indicate  the  leg  to  which  the  bone 
belongs. 

Articulations. — With  the. two  condyles  of  the  femur. 

Attachment  of  Muscles. — To  four  ;  the  rectus,  cruraeus,  vastus  in- 
ternus,  and  vastus  externus,  and  to  the  ligamentum  patellae. 

Tibia. — The  tibia  is  the  large  bone  of  the  leg ;  it  is  prismoid  in 
form,  and  divisible  into  a  shaft,  an  upper  and  lower  extremity. 

The  upper  extremity,  or  head,  is  large,  and  ex- 
panded on  each  side  into  two  tuberosities.    Upon  the        Fig.  42. 
upper  surface  the  tuberosities  are  smooth,  to  articu-  ^ 

late  with  the  condyles  of  the  femur ;  the  internal 
articular  surface  being  oval  and  oblong,  to  corre- 
spond with  the  internal  condyle  ;  and  the  external  wfj. 
broad  and  nearly  circular.  Between  the  two  arti- 
cular surfaces  is  a  spinous  process ;  and  in  front  and 
behind  the  spinous  process  a  rough  depression  giving 
attachment  to  the  anterior  and  posterior  crucial  liga- 
ments. Between  the  two  tuberosities  on  the  front 
aspect  of  the  bone  is  a  prominent  elevation, — the 
tubercle, — for  the  insertion  of  the  ligamentum  patellse, 
and  immediately  above  the  tubercle,  a  smooth  sur- 
face corresponding  with  a  bursa.  Upon  the  outer 
side  of  the  external  tuberosity  is  an  articular  surface, 
for  the  head  of  the  fibula ;  and  upon  the  posterior 
part  of  the  internal  tuberosity  a  depression,  for  the 
insertion  of  the  tendon  of  the  semi-membranosus 
muscle. 

The  shaft  of  the  tibia  presents  three  surfaces ; 
internal,  which  is  subcutaneous  and  superficial;  ex- 
ternal, which  is  concave  and  marked  by  a  sharp 
ridge,  for  the  insertion  of  the  interosseous  mem- 
brane ;  and  posterior,  grooved  for  the  attachment  of 
muscles.  Near  the  upper  extremity  of  the  posterior  surface,  is  an 
oblique  ridge, — the  popliteal  line,  for  the  attachment  of  the  fascia  of 
the  popliteus  muscle ;  and  immediately  below  the  oblique  line,  the 
nutritious  canal,  which  is  directed  downwards. 

The  inferior  extremity  of  the  bone  is  somewhat  quadrilateral,  and 

Fig.  42.  The  tibia  and  fibula  of  the  right  leg,  articulated  and  seen  from  the  front. 
1.  The  shaft  of  the  tibia.  2.  The  inner  tuberosity.  3.  The  outer  tuberosity.  4.  The 
spinous  process.  5.  The  tubercle.  6.  The  internal  subcutaneous  surface  of  the  shaft. 
7.  The  lower  extremity  of  the  tibia.  8.  The  internal  malleolus.  9.  The  shaft  of  the 
fibula.     10,  Its  upper  extremity.     11.  Its  lower  extremity,  the  external  malleolus. 

10* 


114  FIBULA. 

prolonged  on  its  inner  side  into  a  large  process,  the  internal  mal- 
leolus. Behind  the  internal  malleolus,  is  a  broad  and  shallow  groove, 
for  lodging  the  tendons  of  the  tibialis  posticus  and  flexor  longus 
digitorum  ;  and  farther  outwards  another  groove,  for  the  tendon  of 
the  flexor  longus  pollicis.  Upon  the  outer  side  the  surface  is  con- 
cave and  triangular, — rough  above,  for  the  attachnnent  of  the  inter- 
osseous ligament ;  and  smooth  below,  to  articulate  with  the  fibula. 
Upon  the  extremity  of  the  bone  is  a  triangular  smooth  surface,  for 
articulating  with  the  astragalus. 

Developement. — By  three  centres ;  one  for  the  shaft,  and  one  for 
each  extremity. 

Articulations. — With  thi^ee  bones  ;  femur,  fibula,  and  astragalus. 

Attachment  of  Muscles. — To  ten ;  by  the  internal  tuberosity,  to 
the  sartorius,  gracilis,  semitendinosus,  and  semimembranosus;  by 
the  external  tuberosity,  to  the  tibialis  anticus  and  extensor  longus 
digitorum  ;  by  the  tubercle,  to  the  ligamentum  patellae  ;  by  the  ex- 
ternal surface  of  the  shaft,  to  the  tibialis  anticus  ;  and  by  the  poste- 
rior surface,  to  the  popliteus,  soleus,  flexor  longus  digitorum,  and 
tibialis  posticus. 

Fibula. — The  fibula  is  a  long  and  slender  prismoid  bone,  divisible 
into  a  shaft  and  two  extremities. 

The  superior  extremity  or  head  is  thick  and  large,  and  depressed 
upon  the  upper  part  by  a  concave  surface,  which  articulates  with 
the  external  tuberosity  of  the  tibia.  Externally  to  this  surface  is 
a  thick  and  rough  prominence,  for  the  attachment  of  the  external 
lateral  ligaments  of  the  knee-joint,  terminated  behind  by  a  styloid 
process,  for  the  insertion  of  the  tendon  of  the  biceps. 

The  lower  extremity  is  flattened  from  without  inwards,  and  pro- 
longed downwards  beyond  the  articular  surface  of  the  tibia,  form- 
ing the  external  malleolus.  Its  external  side'  presents  a  rough  and 
triangular  surface,  which  is  subcutaneous.  Upon  the  internal  surface 
is  a  smooth  triangular  facet,  to  articulate  with  the  astragalus ;  and 
a  rough  depression,  for  the  attachment  of  the  interosseous  ligament. 
The  anterior  border  is  thin  and  sharp,  and  the  posterior,  broad  and 
grooved,  for  the  tendons  of  the  peronei  muscles. 

To  place  the  bone  in  its  proper  position,  and  ascertain  to  which 
leg  it  belongs,  let  the  inferior  or  flattened  extremity  be  directed 
downwards,  and  the  narrow  border  of  the  malleolus  forwards ;  the 
triangular  subcutaneous  surface  will  then  point  to  the  side  corre- 
sponding with  the  limb  of  which  the  bone  forms  a  part. 

The  shaft  of  the  fibula  is  prismoid,  and  presents  three  surfaces ; 
external,  internal,  and  posterior ;  and  three  borders.  The  external 
surface  is  the  broadest  of  the  three ;  it  commences  upon  the  anterior 
part  of  the  bone  above,  and  curves  around  it  so  as  to  terminate 
upon  its  posterior  side  below.  The  surface  is  completely  occupied 
by  the  two  peronei  muscles.  The  internal  surface  commences  on 
the  side  of  the  superior  articular  surface,  and  terminates  below,  by 
narrowing  to  a  ridge,  which  is  continuous  with  the  anterior  border 


TARSUS —  ASTRAGALUS. 


115 


-With  the  tibia  and  astragalus. 


Fig.  43. 


of  the  malleolus.     It  is  marked  along  its  middle  by  the  interosseous 
ridge,  which  is  lost  above  and  below  in  the  inner  border  of  the  bone. 

The  posterior  surface  is  twisted  like  the  external,  it  commences 
above  on  the  posterior  side  of  the  bone,  and  terminates  below  on  its 
internal  side  ;  at  about  its  middle  is  the  nutritious  foramen,  which  is 
directed  downwards. 

The  internal  border  commences  superiorly  in  common  with  the 
interosseous  ridge,  and  bifurcates  inferiorly  into  two  lines,  which 
bound  the  triangular  subcutaneous  space  of  the  external  malleolus. 
The  external  border  begins  at  the  base  of  the  styloid  process  upon 
the  head  of  the  fibula,  and  winds  around  the  bone,  following  the  di- 
rection of  the  corresponding  surface.  The  posterior  border  is  sharp 
and  prominent,  and  is  lost  inferiorly  in  the  interosseous  ridge. 

Developement. — By  three  centres  ;  one  for  the  shaft,  and  one  for 
each  extremity. 

Articulations.- 

Attachment  of  Muscles. — To  nine  ;  by  the  head,  to  the  tendon  of 
the  biceps  and  soleus  ;  by  the  shaft, — its  external  surface, — to  the 
peroneous  longus  and  brevis ;  internal  surface,  to  the  extensor  lon- 
gus  digitorum,  extensor  proprius  pollicis,  peroneus  tertius,  and  tibia- 
lis posticus;  by  the  posterior  surface,  to  the 
popliteus  and  flexor  longus  pollicis. 

Tarsus. — The  bones  of  the  tarsus  are  seven 
in  number ;  viz.  the  astragalus,  os  calcis,  sca- 
phoid, internal,  middle,  and  external  cuneiform 
and  cuboid. 

The  Astragalus  may  be  recognised  by  a 
rounded  head,  a  broad  articular  facet  upon  its 
convex  surface,  and  two  articular  facets,  sepa- 
rated by  a  deep  groove,  upon  its  concave  sur- 
face. 

The  bone  is  divisible  into  a  superior  and  in- 
ferior surface,  an  external  and  internal  border, 
and  an  anterior  and  posterior  extremity.  The 
superior  surface  is  convex,  and  presents  a  large 
quadrilateral  and  smooth  facet,  somewhat  broad- 
er in  front  than  behind,  to  articulate  with  the 
tibia.  The  inferior  surface  is  concave,  and 
divided  by  a  deep  and  rough  groove,  which 
lodges  a  strong  interosseous  ligament,  into  two 
facets — the  posterior  large  and  quadrangular, 
and  the  anterior  smaller  and  elliptic, — which 
articulate  with  the  os  calcis.   The  internal  border  is  flat  and  irregu- 

Fig.  43.  The  dorsal  surface  of  the  left  foot,  t.  The  astragalus;  its  superior  quad- 
rilateral and  articular  surface.  2.  The  anterior  extremity  of  the  astragalus,  which 
articulates  with  (4)  the  scaphoid  bone.  3.  The  os  calcis.  4.  The  scaphoid  bone.  5. 
internal  cuneiform  bone. .  6.  The  middle  cuneiform  bone.  7.  The  external  cuneiform 
bone  8.  The  cuboid  bone.  9.  The  metatarsal  bones  of  the  first  and  second  toes. 
10.  The  first  phalanx  of  the  great  toe.  11.  The  second  phalanx  of  the  great  toe.  1^. 
The  first  phalanx  of  the  second  toe.     13.  Its  second  phalanx.     14.  Its  third  phalanx. 


116  OS  CALCIS SCAPHOID, 

lar,  and  marked  by  a  pyriform  articular  surface,  for  the  inner  mal- 
leolus. The  external  presents  a  large  triangular  articular  facet,  for 
the  external  malleolus,  and  is  rough  and  concave  in  front.  The 
anterior  extremity  presents  a  rounded  head,  surrounded  by  a  con- 
striction somewhat  resembling  a  neck  ;  and  the  -posterior  extremity 
is  narrow,  and  marked  by  a  deep  groove,  for  the  tendon  of  the 
flexor  longus  pollicis. 

Hold  the  astragalus  with  the  broad  articular  surface  upwards, 
and  the  rounded  head  forwards ;  the  triangular  lateral  articular 
surface  will  point  to  the  side  to  which  the  bone  belongs. 

Articulations. — With  four  bones ;  tibia,  fibula,  calcis  and  sca- 
phoid. 

The  Os  Calcis  may  be  known  by  its  large  size  and  oblong  figure, 
by  the  large  and  irregular  portion  which  forms  the  heel,  and  by  two 
articular  surfaces,  separated  by  a  deep  groove  upon  its  upper  side. 

The  OS  calcis  is  divisible  into  four  surfaces, — superior,  inferior, 
external,  and  internal ;  and  two  extremities, — anterior  and  poste- 
rior. The  superior  surface  is  convex  behind  and  irregularly  con- 
cave in  front,  where  it  presents  two  and  sometimes  three  articular 
facets,  divided  by  a  broad  and  shallow  groove,  for  the  interosseous 
ligament.  The  inferior  surface  is  convex  and  rough,  and  bounded 
posteriorly  by  the  two  inferior  tuberosities,  of  which  the  internal 
is  broad  and  large,  and  the  external  smaller  and  prominent.  The 
external  surface  is  convex  and  subcutaneous,  and  marked  towards 
its  anterior  third  by  two  grooves,  often  separated  by  a  tubercle  for 
the  tendons  of  the  peroneus  longus  and  brevis.  The  internal  surface 
is  concave  and  grooved,  for  the  tendons  and  vessels  which  pass  into 
the  sole  of  the  foot.  At  the  anterior  extremity  of  this  surface  is  a  pro- 
jecting process,  which  supports  the  anterior  articulating  surface  for 
the  astragalus,  and  serves  as  a  pulley  to  the  tendon  of  tiie  flexor  lon- 
gus digitorum.  Upon  the  anterior  extremity  is  a  flat  articular  surface 
surmounted  by  a  rough  projection,  which  affords  one  of  the  guides 
to  the  surgeon  in  the  performance  of  Chopart's  operation.  The 
posterior  extremity  is  prominent  and  convex,  and  constitutes  the 
posterior  tuberosity ;  it  is  smooth  for  the  upper  half  of  its  extent, 
where  it  corresponds  with  a  bursa  ;  and  rough  below,  for  the  inser- 
tion of  the  tendo  Achillis  ;  the  lower  part  of  this  surface  is  bounded 
by  the  two  inferior  tuberosities. 

Articulations. — With  two  bones;  the  astragalus  and  cuboid. 

Attachment  of  Muscles. — To  nine  ;  by  the  posterior  tuberosity,  to 
the  tendo  Achillis  and  plantaris  ;  by  the  inferior  tuberosities  and 
under  surface,  to  the  abductor  pollicis,  abductor  minimi  digiti,  flexor 
brevis  digitorum,  flexor  accessorius,  and  flexor  brevis  pollicis,  and 
to  the  plantar  fascia ;  and  by  the  external  surface,  to  the  extensor 
brevis  digitorum. 

Tlie  Scaphoid  bone  may  be  distinguished  by  its  boat-like  figure, 
concave  on  one  side,  and  convex  with  three  facets  upon  the  other. 
It  presents  for  examination  an  anterior  and  posterior  surfiice,  a  supe- 
rior and  inferior  border,  and  two  extremities — one  broad,  the  other 


CUNEIFORM  BONES.  117 

pointed  and  thick.  The  anterior  surface  is  convex,  and  divided  into 
three  facets,  to  articulate  with  the  three  cuneiform  bones ;  and  the 
'posterior  concave,  to  articulate  with  the  rounded  head  of  the  astra- 
galus. The  superior  border  is  convex  and  rough,  and  the  ivferior 
somewhat  concave  and  irregular.  The  external  extremity  is  broad 
and  rough,  and  the  internal  pointed  and  projecting,  so  as  to  form  a 
tuberosity. 

If  the  bone  be  held  so  that  the  convex  surface  with  three  facets 
look  forwards,  and  the  convex  border  upwards,  the  broad  extremity- 
will  point  to  the  side  corresponding  with  the  foot  to  which  the  bone 
belongs. 

Articulations. — With  four  bones ;  astragalus  and  three  cuneiform 
bones. 

Attachment  of  Muscles. — To  the  tendon  of  the  tibialis  posticus. 

The  Internal  Cuneiform  may  be  known  by  its  irregular  wedge- 
shape,  and  by  being  larger  than  the  two  other  bones  bearing  the 
same  name.  It  presents  for  examination  a  convex  and  a  concave 
surface,  a  long  and  a  short  articular  border,  and  a  small  and  a 
large  extremity. 

Place  the  bone  so  that  the  small  extremity  may  look  upwards  and 
the  long  articular  border  forwards,  the  concave  surface  will  point  to 
the  side  corresponding  with  the  foot  to  which  it  belongs. 

The  convex  surface  is  internal  and  free,  and  assists  in  forming 
the  inner  border  of  the  foot,  and  the  concave  is  exterhal,  and  in 
apposition  with  the  middle  cuneiform  and  second  metatarsal  bone; 
the  long  border  articulates  with  the  metatarsal  bone  of  the  great 
toe,  and  the  short  border  with  the  scaphoid  bone.  The  small  extre- 
mity is  sharp,  and  the  larger  extremity  rounded  into  a  broad  tuberosity. 

Articulations. — With  four  bones  ;  a  scaphoid,  middle  cuneiform, 
and  the  two  first  metatarsal  bones. 

Attachment  of  Muscles. — To  the  tibialis  anticus,  and  posticus. 

The  Middle  Cuneiform  is  the  smallest  of  the  three ;  it  is  wedge- 
shaped,  the  broad  extremity  being  placed  upwards,  and  the  sharp 
end  downwards  in  the  foot.  It  presents  for  examination  four  arti- 
cular surfaces  and  two  extremities.  The  anterior  and  posterior  sur- 
faces have  nothing  worthy  of  remark.  One  of  the  lateral  surfaces 
has  a  long  articular  facet,  extending  its  whole  length  for  the  inter- 
nal cuneiform ;  the  other  has  only  a  partial  articular  facet  for  the 
external  cuneiform  bone. 

If  the  bone  be  held  so  that  the  square  extremity  looks  upwards,  the 
broadest  side  of  the  square  being  towards  the  holder,  the  small  and 
partial  articular  surface  will  point  to  the  side  to  which  the  bone 
belongs. 

Articulations. — With  four  bones;  scaphoid,  internal  and  external 
cuneiform,  and  second  metatarsal  bone. 

Attachment  of  Muscles. — To  the  flexor  brevis  pollicis. 

The  External  Cuneiform  is  intermediate  in  size  between  the  two 
preceding,  and  placed,  like  the  middle,  with  the  broad  end  upwards 
and  the  sharp  extremity  downwards.     It  presents  for  examination 


118  CUBOID — METATARSAL  BONES. 

five  surfaces,  and  a  superior  and  an  inferior  extremity.  The  wpiper 
extremity  is  flat,  of  an  oblong  square  form,  and  bevelled  posteriorly 
at  the  expense  of  the  outer  surface,  into  a  sharp  edge. 

If  the  bone  be  held  so  that  the  square  extremity  look  upwards 
and  the  sharp  border  backwards,  the  bevelled  surface  will  point  to 
the  side  corresponding  with  the  foot  to  which  the  bone  belongs. 

Articulations. — With  six  bones  ;  scaphoid,  middle  cuneiform,  cu- 
boid, and  second,  third,  and  fourth  metatarsal  bones. 

Attachment  of  Muscles. — To  its  inferior  extremity,  the  flexor 
brevis  pollicis. 

The  Cuboid  Bone  is  irregularly  cuboid  in  form,  and  marked 
upon  its  under  surface  by  a  deep  groove,  for  the  tendon  of  the 
peroneus  longus  muscle.  It  presents  for  examination  six  surfaces, 
three  articular  and  three  non-articular.  The  non-articular  surfaces 
are  the  swperior,  which  is  slightly  convex,  and  assists  in  forming 
the  dorsum  of  the  foot ;  the  inferior,  marked  by  a  prominent  ridge 
and  a  deep  grove,  for  the  tendon  of  the  peroneus  longus ;  and  an 
external,  the  smallest  of  the  whole,  and  deeply  notched  by  the  com- 
mencement of  the  peroneal  groove.  The  articular  surfaces  are  the 
posterior,  which  is  of  large  size,  and  concavo-convex,  to  articulate 
with  the  OS  calcis  ;  anterior,  of  smaller  size,  divided  by  a  ridge 
into  two  facets  for  the  fourth  and  fifth  metatarsal  bones ;  and 
internal,  a  small  oval  articular  facet,  upon  a  large  and  quadran- 
gular surface,  for  the  external  cuneiform  bone. 

If  the  bone  be  held  so  that  the  plantar  surface,  with  the  peroneal 
groove,  look  downwards,  and  the  largest  articular  surface  back- 
wards, the  small  non-articular  surface,  marked  by  the  deep  notch, 
will  point  to  the  side  corresponding  with  the  foot  to  which  the  bone 
belongs. 

Articulations. — With  four  bones ;  os  calcis,  external  cuneiform, 
and  fourth  and  fifth  metatarsal  bones. 

Attachment  of  Muscles. — To  three  ;  the  flexor  brevis  pollicis, 
adductor  pollicis,  and  flexor  brevis  minimi  digiti. 

Upon  a  consideration  of  the  tarsus  it  will  be  observed,  that  each 
bone  artici^'lates  with  four  adjoining  bones,  with  the  exception  of 
the  OS  calcis,  which  articulates  with  two,  and  the  external  cunei- 
form with  six. 

Developement. — By  a  single  centre  for  each  bone,  with  the  ex- 
ception of  the  OS  calcis,  which  has  two  centres  of  ossification;  the 
second  centre  makes  its  appearance  at  about  the  ninth  year,  and  is 
not  united  with  the  preceding  until  the  fifteenth. 

The  Metatarsal  Boives,  five  in  number,  are  long  bones,  and 
divisible  therefore  into  a  shaft  and  two  extremities.  The  shaft  is 
prismoid,  and  compressed  from  side  to  side  ;  the  posterior  extremity, 
or  base,  is  square-shaped,  to  articulate  with  the  tarsal  bones  and 
with  each  other;  and  the  anterior  extremity  presents  a  rounded 
head,  circumscribed  by  a  neck,  to  articulate  with  the  first  row  of 
phalanges. 


METATARSAL  BONES. 


119 


arger  than 


Fig.  44. 


Peculiar  Metatarsal  Bones. — The  first  is  shorter  and 
the  rest,  forming  the  inner  border  of  the  foot ;  its  posterior  extremity 
presents  only  one  articular  surface  on  the  side, 
and  an  oval  rough  surface  upon  a  prominent 
process  beneath,  for  the  insertion  of  the  tendon 
of  the  peroneus  longus.  The  anterior  extremity 
has,  upon  its  plantar  surface,  two  grooved 
facets,  for  sesamoid  bones. 

The  second  is  the  longest  and  largest  of  the 
remaining  metatarsal  bones ;  it  presents  at  its 
base  three  articular  facets,  for  the  three  cunei- 
form bones ;  a  large  oval  facet,  but  often  no 
articular  surface,  on  its  inner  side,  to  articulate 
with  the  metatarsal  bone  of  the  great  toe,  e.  nd 
two  externally  for  the  metatarsal  bone. 

The  third  may  be  known  by  two  facets  upon 
the  outer  side  of  its  base,  corresponding  with 
the  second,  and  may  be  distinguished  by  its 
smaller  size. 

The  fourth  may  be  distinguished  by  its 
smaller  size,  and  by  having  a  single  articular 
surface  on  each  side  of  the  base. 

The Jifth  is  recognised  by  its  broad  base,  and 
by  the  absence  of  an  articular  surface  upon  its 
outer  side. 

Developement. — Each  bone  by  tivo  centres ;  one  for  the  body  and 
one  for  the  digital  extremity  in  the  four  outer  metatarsal  bones ;  and 
one  for  the  body,  the  other  for  the  base  in  the  metatarsal  bone  of 
the  great  toe. 

Articulations. — With  the  tarsal  bones  by  one  extremity,  and  with 
the  first  row  of  phalanges  by  the  other.  The  number  of  tarsal 
bones  with  which  each  metatarsal  articulates  from  within  outwards, 
is  the  same  as  between  the  metacarpus  and  carpus, — one  for  the 
fiirst,  three  for  the  second,  one  for  the  third,  two  for  the  fourth,  and 
one  for  the  fifth;  forming  the  cipher  13121.  ^ 

Attachment  of  Muscles. — To  fourteen  ;  to  the  first,  the  peroneus 
longus  and  first  dorsal  interosseous  muscle;  to  the  second,  two  dor- 
sal interossei  and  transversus  pedis;  to  the  third,  two  dorsal  and 
one  plantar  interosseous,  adductor  pollicis  and  transversus  pedis  ;  to 
the  fourth,  two  dorsal  and  one  plantar  interosseous  and  adductor 
pollicis ;  to  the  fifth,  one  dorsal  and  one  plantar  interosseous,  pero- 

Fig.  44.  The  solw^f  the  left  foot.  1.  The  inner  tuberosity  of  the  os  calcis.  2.  The 
outer  tuberosity.  3.  The  groove  for  the  tendon  of  the  flexor  long^us  digiiorutn.  4.  The 
rounded  head  of  the  astragalus.  5.  The  scaphoid  bone.  6.  Its  tuberosity.  7.  The 
internal  cuneiform  bone ;  its  broad  extremity.  8.  The  middle  cuneiform  bone.  9. 
The  external  cuneiform  bone.  10,  11.  The  cuboid  bone.  11.  Refers  to  the  g-roove  for 
the  tendon  of  the  peroneus  long-us.  12,  12.  The  metatarsal  bones.  13,  13.  The  first 
phalanges.  14,  14.  The  second  phalanges  of  the  four  lesser  toes.  15,  15.  The  third, 
or  ungual  phalanges  of  the  four  lesser  toes.     16.  The  last  phalanx  of  the  great  toe. 


120  PHALANGES — SESAMOID  BONES. 

neus  brevis,  peroneus  tertius,  abductor  minimi  digiti,  flexor  brevis 
minimi  digiti,  and  transversus  pedis. 

Phala.vges. — There  are  two  phalanges  in  the  great  toe,  and  three 
in  the  other  toes,  as  in  the  hand.  They  are  long  bones,  divisible 
into  a  central  portion  and  extremities. 

The  phalanges  of  the  first  row  are  convex  above,  concave  upon 
the  under  surface,  and  compressed  from  side  to  side.  The  posterior 
extremity  has  a  single  concave  articular  surface,  for  the  head  of  the 
metatarsal  bone ;  and  the  anterior  extremity,  a  pulley-like  surface, 
for  the  second  phalanx. 

The  second  phalanges  are  short  and  diminutive,  but  somewhat 
broader  than  the  first  row. 

The  third,  or  ungual  phalanges,  including  the  second  phalanx  of 
the  great  toe,  are  flattened  from  above  downwards,  and  spread  out 
laterally  at  the  base,  to  articulate  with  the  second  row,  and,  at  the 
opposite  extremity,  to  support  the  nail  and  the  rounded  extremity  of 
the  toe. 

Deoehpement. — By  two  centres  ;  one  for  the  body  and  one  for  the 
metacarpal  extremity. 

Articulations. — The  first  row  with  the  metatarsal  bones  and  second 
phalanges ;  the  second,  of  the  great  toe  with  the  first  phalanx,  and 
of  the  other  toes  with  the  first  and  third  phalanges;  and  the  third, 
with  the  second  row.  * 

Attachment  of  Muscles. — To  twenty-three ;  to  the  jirst  phalanges ; 
great  toe,  the  innermost  tendon  of  the  extensor  brevis  digitorum,  ab- 
ductor pollicis,  adductor  pollicis,  flexor  brevis  pollicis,  and  transver- 
sus pedis  ;  second  toe,  first  dorsal  and  first  palmar  interosseous  and 
lumbricalis ;  third  toe,  second  dorsal  and  second  palmar  interosseous 
and  lumbricalis ;  fourth  toe,  third  dorsal  and  third  palmar  interos- 
seous and  lumbricalis ;  fifth  toe,  fourth  dorsal  interosseous,  abductor 
minimi  digiti,  flexor  brevis  minimi  digiti,  and  lumbricalis.  Second 
phalanges  ;  great  toe,  extensor  longus  pollicis,  and  flexor  longus  pol- 
licis ;  other  toes,  one  slip  of  the  common  tendon  of  the  extensor  lon- 
gus digitorum,  and  extensor  brevis  digitorum,  and  flexor  brevis  digi- 
torum. Third  phalanges ;  two  slips  of  the  common  tendon  of  the 
extensor  longus  and  extensor  brevis  digitorum,  and  the  flexor  longus 
digitorum. 

Sesamoid  Bones. — These  are  small  osseous  masses,  developed  in 
those  tendons  which  exert  a  certain  degree  of  force  upon  the  sur- 
face over  which  they  glide,  or  where,  by  continued  pressure  and 
friction,  the  tendon  would  become  a  source  of  irritation  to  neigh- 
bouring parts,  as  to  joints.  The  best  example  of  a  sesamoid  bone  is 
the  patella,  developed  in  the  common  tendon  of  th^  quadriceps  ex- 
tensor, and  resting  upon  the  front  of  the  knee-joint.  Besides  the  pa- 
tella, there  are  four  pairs  of  sesamoid  bones  included  in  the  number 
of  pieces  which  compose  the  skeleton,  two  upon  the  metacarpo- 
phalangeal articulation  of  each  thumb,  and  existing  in  the  tendons  of 
insertion  of  the  flexor  brevis  pollicis,  and  two  upon  the  correspond- 
ing joint  in  the  foot,  in  the  tendons  of  the  pnpscles  inserted  into  the 


SESAMOID  BONES.  121 

base  of  the  first  phalanx.  Tn  addition  to  these  there  is  often  a  sesa- 
moid bone  upon  the  metacarpo-phalangeal  joint  of  the  httle  finger, 
and  upon  the  corresponding  joint  in  the  foot,  in  the  tendons  inserted 
into  the  base  of  the  first  phalanx ;  there  is  one  also  in  the  tendon  of 
the  peroneus  longus  muscle,  where  it  glides  through  the  groove  in 
the  cuboid  bone ;  sometimes  in  the  tendons,  as  they  wind  around  the 
inner  and  outer  malleolus ;  in  the  psoas  and  iliacus,  where  they  glide 
over  the  body  of  the  os  pubis ;  and  in  the  external  head  of  the  gas- 
trocnemius. 

The  bones  of  the  tympanum,  belonging  to  the  apparatus  of  hear- 
ing, will  be  described  with  the  anatomy  of  the  ear. 


11 


CHAPTER    II. 

ON  THE  LIGAMENTS. 

The  bones  are  variously  connected  with  each  other  in  the  con- 
struction of  the  skeleton,  and  the  connexion  between  any  two  bones 
constitutes  a  joint  or  articulation.  If  the  joint  be  immovable,  the 
surfaces  of  the  bones  are  appUed  in  direct  contact ;  but  if  motion 
be  intended,  the  opposing  surfaces  are  expanded,  and  coated  by  an 
elastic  substance,  named  cartilage  ;  a  fluid  secreted  by  a  membrane 
closed  on  all  sides  lubricates  their  surface,  and  they  are  firmly  held 
together  by  means  of  short  bands  of  glistening  fibres,  which  are 
called  ligaments  (ligare,  to  bind).  The  study  of  ligaments  is  named 
syndesmology  {dvv  together,  (^stf/xoj,  bond),  which,  with  the  anatomy 
of  the  articulations,  forms  the  subject  of  the  present  chapter. 

The  forms  of  articulation  met  with  in  the  human  frame  may  be 
considered  under  three  classes  : — Synarthrosis,  Amphi-arthrosis  and 
Diarthrosis. 

Synarthrosis  (tfov,  ag^^wtfig,  articulation)  is  expressive  of  the  fixed 
form  of  joint  in  which  the  bones  are  immovably  connected  with 
each  other.  The  kinds  of  synarthrosis  are  four  in  number.  1. 
Sutura.  2.  Harmonia.  3.  Schindylesis.  4.  Gomphosis.  The  cha- 
racters of  the  three  first  have  been  sufficiently  explained  in  the  pre- 
ceding chapter,  p.  74.  It  is  here  only  necessary  to  state  that  in  the 
construction  of  sutures,  the  substance  of  the  bones  is  not  in  imme- 
diate contact,  but  it  is  separated  by  a  layer  of  membrane  which  is 
continuous  externally  with  the  pericranium  and  internally  with  the 
dura  mater.  It  is  the  latter  connexion  which  gives  rise  to  the  great 
difficulty  sometimes  experienced  in  tearing  the  calvarium  from  the 
dura  mater.  Cruveilhier  describes  this  interposed  membrane  as  the 
sutural  cartilage :  I  never  saw  any  structure  in  the  sutures,  which 
could  be  regarded  as  cartilage,  and  the  history  of  the  formation  of 
the  cranial  bones  would  seem  to  point  to  a  different  explanation. 
The  fourth,  Gomphosis  (/ofxqjoj,  a  nail)  is  expressive  of  the  insertion 
of  one  bone  into  another,  in  the  same  manner  that  a  nail  is  fixed 
into  a  board  ;  this  is  illustrated  in  the  articulation  of  the  teeth  with  the 
alveoli  of  the  maxillary  bones. 

Amphi-arthrosis  {dii^cpi,  both,  af^g«*»g)  is  a  joint  intermediate  in 
aptitude  for  motion  between  the  immovable  synarthrosis  and  the 
movable  diarthrosis.  It  is  constituted  by  the  approximation  of  sur- 
faces partly  coated  with  cartilage  lined  by  synovial  membrane,  and 
partly  connected  by  the  interosseous  ligaments,  or  by  the  interven- 


ARTICULATIONS MOVEMENTS.  123 

tion  of  an  elastic  fibro-cartilage  which  adheres  to  the  ends  of  both 
bones.  Examples  of  this  articulation  are  seen  in  the  union  between 
the  bodies  of  the  vertebrge,  of  the  sacrum  with  the  coccyx,  of  the 
two  first  pieces  of  the  sternum,  the  sacro-iliac  and  pubic  sym- 
physes, ((Jiv,(pusiv,  to  grow  together),  and  according  to  some,  of  the 
necks  of  the  ribs,  with  the  transverse  processes. 

DiARTHROsis  {Sia,  through,  a^^^wff'ij)  is  the  movable  articulation, 
which  constitutes  by  far  the  greater  number  of  the  joints  of  the 
body.  The  degree  of  motion  in  this  class  has  given  rise  to  a  sub- 
division into  three  genera,  Arthrodia,  Ginglymus,  and  Enarthrosis. 

Arthrodia  is  the  movable  joint  in  which  the  extent  of  motion  is 
slight  and  limited,  as  in  the  articulation  of  the  clavicle,  of  the  ribs, 
articular  processes  of  the  vertebra,  axis  with  the  atlas,  radius  with 
the  ulna,  fibula  with  the  tibia,  carpal  and  metacarpal,  tarsal  and 
metatarsal  bones. 

Ginglymus  {yiyy'kvy.os,  a  hinge)  or  hinge-joint,  is  the  movement  of 
bones  upon  each  other  in  two  directions  only,  viz.  forwards  and 
backwards ;  but  the  degree  of  motion  may  be  very  considerable. 
The  instances  of  this  form  of  joint  are  numerous  ;  they  comprehend 
the  elbow,  wrist,  metacarpo-phalangeal  and  phalangeal  joints  in  the 
upper  extremity;  and  the  knee,  ankle,  metatarso-phalangeal  and 
phalangeal  joints  in  the  lower  extremity.  The  lower  jaw  may  also 
be  admitted  into  this  category,  as  partaking  more  of  the  character 
of  the  hinge-joint  than  of  the  less  movable  arthrodia. 

The  form  of  the  ginglymoid  joint  is  somewhat  quadrilateral,  and 
each  of  its  four  sides  is  provided  with  a  ligament,  which  is  named 
from  its  position,  anterior,  posterior,  internal  or  external  lateral. 
The  lateral  ligaments  are  thick  and  strong,  and  are  the  chief  bond 
of  union  between  the  bones.  The  anterior  and  posterior  are  thin 
and  loose  in  order  to  permit  the  required  extent  of  movement. 

Enarthrosis  {iv,  in,  d^^^wtfi?)  is  the  most  extensive  in  its  range  of 
motion  of  all  movable  joints.  From  the  manner  of  connexion  and 
form  of  the  bones  in  this  articulation,  it  is  called  the  ball  and  socket 
joint.  There  are  three  instances  in  the  body,  viz.  the  hip,  the 
shoulder,  and  the  articulation  of  the  metacarpal  bone  of  the  thumb 
with  the  trapezium. 

The  ball  and  socket  joint  has  a  circular  form ;  and,  in  place  of 
the  four  distinct  ligaments  of  the  ginglymus,  is  enclosed  in  a  bag  of 
ligamentous  membrane,  called  a  capsular  ligament. 

The  kinds  of  articulation  may  probably  be  conveyed  in  a  more 
satisfactory  manner  in  the  tabular  form,  thus : 

Examples. 
^Sutura     ....     bones  of  the  skull. 

<^        fh .  -■     J  Harmonia    .     .     .     superior  maxillary  bones. 
^  "         I  Schindylesis     .     .     vomer  with  rostrum. 

(^Gomphosis  .     .     .     teeth  with  alveoli. 

Amphi-arthrosis     .     Bodies  of  the  vertebrae     .     Symphyses. 
i  Arthrodia     .     .     .     carpal  and  tarsal  bones. 

Diarthrosis        <  Ginglymus  .     .     .     elbow,  w^rist,  knee,  ankle. 
( Enarthrosis       .     .     hip,  shoulder. 


124  STRUCTURE  OF  JOINTS. 

The  motions  permitted  in  joints  may  be  referred  to  four  heads, 
viz.:  1.  Gliding.  2.  Angular  movement.  3.  Circumduction.  4. 
Rotation. 

1.  Gliding  is  the  simple  movement  of  one  articular  surface  upon 
another,  and  exists  to  a  greater  or  less  extent  in  all  the  joints.  In 
the  least  movable  joints,  as  in  the  carpus  and  tarsus,  this  is  the 
only  motion  which  is  permitted. 

'Z.  Angular  movement  may  be  performed  in  four  different  direc- 
tions, either  forwards  and  backwards,  as  in  flexion  and  extension ; 
or  inwards  and  outwards,  constituting  adduction  and  abduction. 
Flexion  and  extension  are  illustrated  in  the  ginglymoid  joint,  and 
exist  in  a  large  proportion  of  the  joints  of  the  body.  Adduction 
and  abduction  conjoined  with  flexion  and  extension,  are  met  with 
complete  only  in  the  most  movable  joints,  as  in  the  shoulder,  the 
hip,  and  the  thumb.  In  the  wrist  and  in  the  ankle  adduction  and 
abduction  are  only  partial. 

3.  Circumduction  can  be  performed  only  in  the  shoulder  and 
hip  joints ;  it  consists  in  the  slight  degree  of  motion  which  takes 
place  in  the  head  of  a  bone  against  its  articular  cavity,  while  the 
extremity  of  the  limb  is  made  to  describe  a  large  circle  upon  a 
plane  surface. 

4.  Rotation  is  the  movement  of  a  bone  upon  its  own  axis,  and 
is  illustrated  in  the  hip  and  shoulder,  or  better  in  the  rotation  of  the 
cup  of  the  radius,  against  the  rounded  articular  protuberance  of  the 
humerus.  Rotation  is  also  observed  in  the  movements  of  the  atlas 
upon  the  axis,  in  which  the  odontoid  process  serves  as  a  pivot  around 
which  the  atlas  turns. 

The  structures  entering  into  the  composition  of  a  joint  are  bone, 
cartilage,  fibro-cartilage,  ligament,  and  synovial  membrane. 

Cartilage  is  an  elastic  and  apparently  homogeneous  substance  of 
a  pearly  whiteness,  which  forms  the  thin  incrustation  upon  the 
articular  surfaces  of  bones.  Upon  convex  surfaces  it  is  thickest  in 
the  centre,  and  thin  towards  the  circumference,  and  presents  upon 
concave  surfaces  an  opposite  arrangement.  It  is  composed  of  a 
number  of  minute  fibres  placed  perpendicularly  to  the  surface, 
attached  by  one  extremity  to  the  bone,  and  forming  by  the  other 
a  smooth  plane,  covered  by  synovial  membrane. 

Fibro-cartilage,  as  expressed  in  its  name,  is  a  compound  struc- 
ture, consisting  in  the  combination  of  fibrous  and  cartilaginous  tis- 
sues in  variable  proportions.  It  is  found  in  joints  under  three  forms: 
1.  Of  interarticular  fibro-cartilages.  2.  Of  fibro-cartilages  of  cir- 
cumference.    3.  Of  intervertebral  substance. 

The  interarticular  fibro-cartilages  (menisci,)  composed  chiefly  of 
cartilage,  are  found  in  the  articulations  of  the  lower  jaw,  sternal 
and  acromial  end  of  the  clavicle,  knee  and  wrist-joint.  The  trian- 
gular cartilage  of  the  wrist  is  not  admitted  by  Dr.  Todd*  among 
the  fibro-carlilages,  but  is  considered  by  him  to  be  merely  an  exten- 

*  Cyclopaedia  of  Anatomy  and  Physiology,  article,  Articulation. 


STRUCTURE  OF  JOINTS.  125 

sion  of  the  cartilaginous  incrustation  of  the  inferior  extremity  of  the 
radius. 

The  Jibro-cartilages  of  ciixumference  contain  a  large  proportion 
of  fibrous  tissue;  they  are  situated  upon  the  margins  of  the  glenoid 
and  cotyloid  cavities,  and  serve  to  deepen  those  articulations,  and 
at  the  same  time  to  protect  the  edges  from  injurious  pressure. 

The  intervertebral  substance  is  composed  of  concentric  lamellae  of 
fibrous  structure,  surrounding,  towards  the  centre,  a  soft  cartilagi- 
nous and  almost  pulpy  mass.  The  fibres  of  which  the  lamellte  are 
formed,  interlace  with  each  other  obliquely  ;  the  intervening  meshes 
being  filled  with  a  soft  cartilaginous  substance,  and  becoming  larger 
towards  the  central  pulp. 

Ligament  is  composed  of  numerous  straight  fibres  collected  toge- 
ther, and  arranged  into  short  bands  (fasciculi)  of  various  breadth, 
or  interwoven  so  as  to  form  a  broad  layer,  which  completely 
surrounds  the  articular  extremities  of  the  bones,  and  constitutes  a 
capsular  ligament. 

All  the  ligaments  of  the  joints  consist  of  fibres  of  this  kind,  which 
are  white,  glistening  and  inelastic.  But  besides  these  there  are 
other  ligaments,  which  are  composed  of  yellow  elastic  tissue,  and 
serve  to  connect  parts  which  are  subject  to  frequent  and  conside- 
rable separation,  as  the  arches  of  the  vertebrae,  where  they  form 
the  ligamenta  subflava. 

The  synovial  membrane  is  a  thin  membranous  layer,  which  invests 
the  articular  cartilages  of  the  bones,  and  is  thence  reflected  upon 
the  surfaces  of  the  ligaments  which  surround  and  enter  into  the 
composition  of  a  joint.  It  resembles  the  serous  membranes  in  being 
a  shut  sac,  and  secretes  a  transparent  and  viscous  fluid,  which  is 
named  synovia.  Synovia  is  an  alkaline  secretion,  containing  albu- 
men, which  is  coagulable  at  a  boiling  temperature.  The  continua- 
tion of  this  membrane  over  the  surface  of  the  articular  cartilage,  a 
much  agitated  question,  has  lately  been  decided  by  the  interesting 
discoveries  of  Henle,  who  has  ascertained  the  existence  of  an 
epithelium  upon  cartilage  identical  with  that  secreted  by  the  reflected 
portion  of  the  membrane.  In  some  of  the  joints  the  synovial  mem- 
brane is  pressed  into  the  articular  cavity  by  a  cushion  of  fat,  which 
serves  the  purpose  of  facilitating  the  movements  of  the  surfaces.  This 
mass  was  called  by  Havers  the  synovial  gland,  from  an  incorrect 
supposition  that  it  was  the  source  of  the  synovia.  It  is  found  in  the 
hip  and  in  the  knee-joint.  In  the  knee-joint,  moreover,  the  synovial 
membrane  forms  folds,  which  are  most  improperly  named  ligaments, 
— as  the  mucous  and  alar  ligaments, — the  two  latter  being  an 
appendage  to  the  cushion  of  fat.  Besides  the  synovial  membranes 
entering  into  the  composition  of  joints,  there  are  numerous  smaller 
sacs  of  a  similar  kind  interposed  between  surfaces  which  move 
upon  each  other  so  as  to  cause  friction  ;  they  are  often  associated 
with  the  articulations.  These  are  the  burscB  mucoscB ;  they  are 
shut  sacs,  analogous  in  structure  to  synovial  membranes,  and 
secreting  a  similar  synovial  fluid. 

11*  4 


126  IIGAMENTS  OF  THE  TRUNK. 


ARTICULATIONS. 

The  joints  may  be  arranged,  according  to  a  natural  division, 
into  ttiose  of  the  trunk,  those  of  the  upper  extremity,  and  those  of 
the  lower  extremity. 

Ligaments  of  the  Trunk. — The  articulations  of  the  trunk  are 
divisible  into  nine  groups,  viz. : 

1.  Of  the  vertebral  column. 

2.  Of  the  atlas  with  the  occipital  bone. 

3.  Of  the  axis,  with  the  occipital  bone. 

4.  Of  the  atlas,  with  the  axis. 

5.  Of  the  lower  jaw. 

6.  Of  the  ribs,  with  the  vertebrae. 

7.  Of  the  ribs,  with  the  sternum,  and  with  each  other. 

8.  Of  the  vertebral  column,  with  the  pelvis. 

9.  Of  the  pelvis. 

1.  Articulation  of  the  Vertebral  Column. — The  ligaments  connect- 
ing together  the  different  pieces  of  the  vertebral  column,  admit  of 
the  same  arrangement  with  that  of  the  vertebrae  themselves.  Thus 
the  ligaments 

Of  the  bodies  are  the —  Anterior  common  ligament. 

Posterior  common  ligament. 
Intervertebral  substance. 

Of  the  arches, —  Ligamenta  subflav^. 

Of  the  articular  processes, —    Capsular  ligaments. 

Synovial  membranes. 
Of  the  spinous  processes, —        Inter-spinous. 

Supra-spinous. 

Of  the  transverse  processes, —  Inter-transverse. 

Bodies. — The  anterior  common  ligament  is  a  broad  and  riband- 
like band  of  ligamentous  fibres,  extending  along  the  front  surface  of 
the  vertebral  column,  from  the  axis  to  the  sacrum.  It  is  intimately 
connected  with  the  intervertebral  substances,  and  less  closely  with 
the  bodies  of  the  vertebrae. 

The  anterior  common  ligament  is  thicker  in  the  dorsal  than  in 
the  cervical  and  lumbar  regions,  and  consists  of  a  median  and  two 
lateral  portions,  separated  from  each  other  by  a  series  of  openings 
for  the  passage  of  vessels.  The  ligament  is  composed  of  fibres  of 
various  length  closely  interwoven  with  each  other;  the  deeper  and 
shorter  crossing  the  intervertebral  substances  from  one  vertebra  to 
the  next ;  and  the  superficial  and  longer  fibres  crossing  three  or 
four  vertebrae. 

Relations. — The  anterior  common  ligament  is  in  relation  by  its 
posterior  or  vertebral  surface,  with  the  intervertebral  substances,  the 


LIGAMENTS  OF  THE  VERTEBRAL  COLUMN. 


127 


Fig.  45. 


bodies  of  the  vertebras  and  with  the  vessels,  principally  veins, 
which  separate  its  central  from  its  lateral  portions.  By  its  ante- 
rior or  visceral  surface  it  is  in  relation  in  the  neck,  with  the  longus 
colli  muscles,  the  pharynx  and  the 
oesophagus ;  in  the  thoracic  re- 
gion, with  the  aorta,  the  vena 
azygos,  and  thoracic  duct ;  and  in 
the  lumbar  region,  with  the  aorta, 
right  renal  artery,  right  lumbar 
arteries,  arteria  sacra  media,  vena 
cava  inferior,  left  lumbar  veins, 
receptaculum  chyli,  the  com- 
mencement of  the  thoracic  duct, 
and  the  tendons  of  the  lesser  mus- 
cle of  the  diaphragm  with  the 
fibres  of  which  the  ligamentous  fibres  interlace. 

The  posterior  common  ligament  lies  upon  the  posterior  surface  of 
the  bodies  of  the  vertebra,  and  extends  from  the  axis  to  the  sacrum. 
It  is  broad  opposite  the  intervertebral  substances,  to  which  it  is 
closely  adherent ;  and  narrow  and  thick  over  the  bodies  of  the  ver- 
tebrse,  from  which  it  is  separated  by  the  veins  of  the  base  of  the 
vertebra.  It  is  composed  like  the  anterior  ligament  of  shorter  and 
longer  fibres  which  are  disposed  in  a  similar  manner. 

Relations. — The  posterior  common  ligament  is  in  relation  by  its 
anterior  surface  with  the  intervertebral  substances,  the  bodies  of 
the  vertebrae,  and  with  the  venee  basis  vertebrae ;  and  by  its  foste- 
rior  surface  with  the  dura  mater  of  the  spinal  cord,  some  loose 
cellular  tissue  and  numerous  small  veins  being  interposed. 

The  intervertebral  substance  is  a  lenticular  disc  of  fibro-cartilage, 
interposed  between  each  of  the  vertebra  from  the  axis  to  the 
sacrum,  and  retaining  them  firmly  in  connexion  with  each  other. 
It  differs  in  thickness  in  different  parts  of  the  column,  and  varies  in 
depth  at  different  points  of  its  extent ;  thus,  it  is  thickest  in  the  lum- 
bar region,  deepest  in  front  in  the  cervical  and  lumbar  regions, 
and  behind  in  the  dorsal  region ;  and  contributes,  in  a  great 
measure,  to  the  formation  of  the  natural  curves  of  the  vertebral 
column. 

Arches. — The  ligamenta  subfava  are  composed  of  yellow  elastic 
tissue,  and  are  situated  between  the  arches  of  the  vertebrae,  from  the 
axis  to  the  sacrum.  From  the  imbricated  position  of  the  laminae 
they  are  attached  to  the  posterior  surface  of  the  vertebra  below,  and 
to  the  anterior  surface  of  the  arch  of  the  vertebra  above,  and  are 
separated  from  each  other  at  the  middle  line  by  a  slight  fissure. 
They  counteract,  by  their  elasticity,  the  efforts  of  the  flexor  muscles 


Fig-,  45.  The  anterior  ligaments  of  the  vertebrte,  and  ligaments  of  the  ribs.  1.  The 
anterior  common  ligament.  2.  The  anterior  costo-vertebral  or  stellate  ligament.  3. 
The  anterior  costo-transverse  ligament.  4.  The  interarticular  ligament  connecting  the 
head  of  the  rib  to  the  intervertebral  substance,  and  separating  the  two  synovial  mem- 
branes of  thip-  articulation. 


'¥' 


128 


LIGAMENTS  OF  THE  VERTEBRAL  COLUMN. 


of  the  trunk;  and  by  preserving  the  upright  position  of  the  spine, 
limit  the  expenditure  of  muscular  force.  They  are  longer  in  the 
cervical  than  in  the  other  regions  of  the  spine,  and  are  thickest  in 
the  lumbar  region. 


Fig-.  46. 


Tig.  47. 


Relations. — The  ligamenta  subflava  are  in  relation  by  both  sur- 
faces with  the  meningo-rachidian  veins,  and  internally  they  are 
separated  from  the  dura  mater  of  the  spinal  cord  by  those  veins  and 
some  loose  cellular  tissue. 

Articular  Processes. — The  ligaments  of  the  articular  processes 
of  the  vertebrae,  are  loose  synovial  capsules,  which  surround  the 
articulating  surfaces.  They  are  protected  on  their  external  side  by 
a  thin  layer  of  ligamentous  fibres. 

Spinous  Processes. — The  inter-spinous  ligaments  are  thin  and 
membranous,  and  are  extended  between  the  spinous  process  in  the 
dorsal  and  lumbar  regions.  They  are  thickest  in  the  latter  region ; 
and  are  in  relation  with  the  multifidus  spinse  muscle  at  each  side. 

The  supraspinous  ligament  is  a  strong  and  inelastic  fibrous 
cord,  which  extends  from  the  apex  of  the  spinous  process  of  the 
last  cervical  vertebra  to  the  sacrum,  being  attached  to  each 
spinous  process  in  its  course ;  it  is  thickest  in  the  lumbar  region. 
The  continuation  of  this  ligament  upwards  to  the  tuberosity  of  the 
occipital  bone,  constitutes  the  rudimentary  ligamentum  nuchas  of 
man.  It  is  strengthened,  as  in  animals,  by  a  thin  slip  from  the 
^inous  process  of  each  of  the  cervical  vertebree. 

Transverse  Processes. — The  inter-transverse  ligaments  are  thin 

Fig,  46.  A  posterior  view  of  the  bodies  of  three  dorsal  vertebrae,  connected  by  their 
intervertebral  substance  (1,  1.)  The  laminae  (2)  have  been  savi^n  away  near  to  the  bodies 
of  the  vertebrae,  and  the  arches  and  processes  removed,  in  order  to  show  (3)  the  poste- 
rior common  lio;amcnt.  A  part  of  one  of  the  openings  in  the  posterior  surface  of  the 
vertebra,  for  the  transmission  of  the  vena  basis  vertebraB,  is  seen  at  4,  by  the  side  of  the 
narrow  and  unattached  portion  of  the  ligament. 

Fig.  47.  An  internal  view  of  the  arches  of  the  vertebrae.  To  obtain  this  view  the 
lamina}  have  been  divided  through  their  pedicles.  1.  One  of  the  ligamenta  subflava. 
2.  The  capsular  ligament  of  one  side. 


LIGAMENTS  OF  THE  VERTEBRAL  COLUMN. 


129 


and  membranous ;  they  are  found  only  between  the  transverse  pro- 
cesses of  the  lower  dorsal  vertebrse. 

2.  Articulation  of  the  Atlas  witk  the  Occipital  hone. — The  ligaments 
of  this  articulation  are  seven  in  number. 

Two  anterior  occipito-atloid. 

Posterior  occipito-atloid. 

Lateral  occipito-atloid. 

Two  capsular. 
Of  the  two  anterior  ligaments  one  is  a  rounded  cord,  situated  in 
the  middle  line,  and  superficially  to  the  other.  It  is  attached  above, 
to  the  basilar  process  of  the  occipital  bone  ;  and  below,  to  the  an- 
terior tubercle  of  the  atlas.  The  deeper  ligament  is  a  hroad  mem- 
branous layer,  attached  above,  to  the  margin  of  the  occipital  fora- 
men ;  and  below,  to  the  whole  length  of  the  anterior  arch  of  the 
atlas.  It  is  in  relation  in  front  with  the  recti  antici  minores  and 
behind  with  the  dura  mater. 


Fig.  48. 


Fig.  49. 


The  "posterior  ligament  is  extremely  thin  and  membranous  ;  it  is 
attached  above,  to  the  margin  of  the  occipital  foramen;  and  below, 
to  the  posterior  arch  of  the  atlas.  It  is  closely  adherent  to  the  dura 
mater,  by  its  inner  surface  ;  and  forms  a  ligamentous  arch  at  each 
side,  for  the  passage  of  the  vertebral  arteries  and  first  cervical 
nerves.    It  is  in  relation  posteriorly  with  the  recti  postici  minores. 

The  lateral  ligaments  are  strong  fasciculi  of  ligamentous  fibres, 

Fig.  48.  An  anterior  view  of  the  ligaments  connecting  the  atlas,  the  axis,  and  the 
occipital  bone.  A  transverse  section  has  been  carried  through  the  base  of  the  sknll, 
dividing  the  basilar  process  of  the  occipital  bone  and  the  petrous  portions  of  the  tempo- 
ral bones.  1.  The  anterior  round  occipito-atloid  ligament.  2,  2.  The  anterior  broad 
occipito-atloid  ligament.  3.  The  commencement  of  the  anterior  common  ligament. 
4.  The  anterior  atlo-axoid ligament,  whicii  is  continuous  inferiorly  with  tiie  commence- 
ment of  the  anterior  common  ligament.  5.  One  of  the  atlo-axoid  capsular  ligaments  ; 
the  one  on  the  opposite  side  (6)  has  been  removed,  to  show  tlie  approximated  surfaces 
of  the  articular  process.  7.  One  of  the  occipito-atloid  capsular  ligaments.  The  most 
external  of  these  fibres  constitute  the  lateral  occipito-atloid  ligament. 

Fig.  49.  The  posterior  ligaments  of  tiie  occipilo-atloid,  and  atlo-axoid  articulations. 
1.  The  atlas.  2.  The  axis.  3.  The  posterior  ligament  of  the  occipito-atloid  articula- 
tion. 4,  4.  The  capsular  and  lateral  ligaments  of  this  articulation.  5.  The  posterior 
ligaments  of  the  atlo-axoid  articulation.  6,  6.  Its  capsular  ligaments.  7.  The  first  of 
the  ligamenta  subflava  passing  between  the  axis  and  the  third  cervical  vertebra.  8,  8. 
Their  capsular  ligaments. 


130 


LIGAMENTS  OF  THE  VERTEBRAL  COLUMN. 


attached  below,  to  the  base  of  the  transverse  process  of  the  atlas  at 
each  side,  and  above  to  the  transverse  process  of  the  occipital  bone. 
With  a  ligamentous  expansion  derived  from  the  vaginal  process  of 
the  temporal  bone,  these  ligaments  form  a  strong  sheath  around  the 
vessels  and  nerves  which  pass  through  the  carotid  and  jugular  fora- 
men. 

The  capsular  ligaments  are  the  thin  and  loose  ligamentous  cap- 
sules, which  surround  the  synovial  membranes  of  the  articulations, 
between  the  condyles  of  the  occipital  bone  and  the  superior  articular 
processes  of  the  atlas.  The  ligamentous  fibres  are  most  numerous 
upon  the  anterior  and  external  part  of  the  articulation. 

The  movements  taking  place  between  the  cranium  and  atlas,  are 
those  of  flexion  and  extension,  giving  rise  to  the  forward  nodding  of 
the  head.  When  this  motion  is  increased  to  any  extent  the  whole 
of  the  cervical  region  concurs  in  its  production. 

3.  Articulation  of  the  Axis  loith  the  Occipital  bone. — The  ligaments 
of  this  articulation  are  three  in  number. — 


Occipito-axoid, 
Two  odontoid. 


Fig.  50. 


The  occipito-axoid  ligament  (appa- 
ratus ligamentosus  colli)  is  a  broad 
band,  which  covers  in  the  odontoid 
process  and  its  ligaments.  It  is  at- 
tached below  to  the  body  of  the  axis, 
and  is  continuous  with  the  posterior 
common  ligament;  superiorly  it  is 
inserted  by  a  broad  expansion,  into 
the  basilar  groove  of  the  occipital 
bone.  It  is  firmly  connected  oppo- 
site the  body  of  the  axis,  with  the 
dura  mater.  It  is  sometimes  de- 
scribed as  consisting  of  a  central  and  two  lateral  portions ;  this  how- 
ever is  an  unnecessary  refinement. 

The  odontoid  ligaments  (alar)  are  two  short  and  thick  fasciculi  of 
fibres,  which  pass  outwards  from  the  apex  of  the  odontoid  process, 
to  the  sides  of  the  occipital  foramen  and  condyles.  A  third  and 
smaller  fasciculus  also  proceeds  from  the  apex  of  the  odontoid  pro- 
cess, to  the  anterior  margin  of  the  foramen  magnum.* 

These  ligaments  serve  to  limit  the  extent  to  which  rotation  of  the 
head  may  be  carried,  hence  they  are  termed  check  ligaments. 

4.  Articulation  of  the  Atlas  with  the  Axis. — The  ligaments  of  this 
articulation  are  five  in  number  : 

Fig.  50.  The  upper  part  of  the  vertebral  canal,  opened  from  behind  in  order  to  show 
the  occipito-axoid  ligament.  1.  The  basilar  portion  of  the  sphenoid  bone.  2.  Section 
of  the  occipital  bone.  .3.  The  atlas,  its  posterior  arch  removed.  4.  The  axis,  the  pos- 
terior  arch  also  removed.  5.  The  occipito-a.xoid  ligament,  rendered  prominent  at  its 
middle  by  the  projection  of  the  odontoid  process.  G.  Lateral  and  capsular  ligament  of 
the  oceipito-atloid  articulation.  7.  Capsular  ligament  between  the  articulating  process 
of  the  atl:i8  and  axis. 

*  Called  7ni(J<Ile  strnight,  ligament. — G. 


LIGAMENTS  OF  THE  VERTEBRAL  COLUMN.  131 

Anterior  atlo-axoid.  Two  capsular. 

Posterior  atlo-axoid.  Transverse. 

The  anterior  ligament  consists  of  ligamentous  fibres,  which  pass 
from  the  anterior  tubercle  and  arch  of  the  atlas  to  the  base  of  the 
odontoid  process  and  body  of  the  axis,  where  they  are  continuous 
with  the  commencement  of  the  anterior  common  ligament,* 

The  posterior  ligament  is  a  thin  and  membranous  layer,  passing 
between  the  posterior  arch  of  the  atlas  and  the  laminai  of  the  axis. 

The  capsular  ligaments  surround 
the  articular  processes  of  the  atlas  Tig-.  51. 

and  axis ;  they  are  loose,  to  permit 
of  the  freedom  of  movement  which 
subsists  between  the  atlas  and  axis. 
The  ligamentous  fibres  are  most 
numerous  on  the  outer  and  anterior 
part  of  the  articulation,  and  the 
synovial  membrane  usually  commu- 
nicates with  the  synovial  cavity  be- 
tween the  transverse  ligament  and 
the  odontoid  process. 

The  transverse  ligament  is  a  strong  ligamentous  band,  which 
arches  across  the  area  of  the  ring  of  the  atlas  from  a  rough  tubercle 
upon  the  inner  surface  of  one  articular  process  to  a  similar  tubercle 
on  the  other.  It  serves  to  retain  the  odontoid  process  of  the  axis 
in  connexion  with  the  anterior  arch  of  the  atlas.  As  it  crosses  the 
odontoid  process,  some  fibres  are  sent  downwards  to  be  attached  to 
the  body  of  the  axis,  and  others  pass  upwards  to  be  inserted  into 
the  basilar  process  of  the  occipital  bone;-]-  hence  the  ligament  has  a 
cross-like  appearance,  and  has  been  denominated  cruciform.  A 
synovial  membrane  is  situated  between  the  transverse  ligament  and 
the  odontoid  process ;  and  another  between  that  process  and  the 
inner  surface  of  the  anterior  arch  of  the  atlas. 

Actions. — It  is  the  peculiar  disposition  of  this  ligament  in  relation 
to  the  odontoid  process,  that  enables  the  atlas,  and  with  it  the  entire 
cranium,  to  rotate  upon  the  axis  ;  the  perfect  freedom  of  movement 
between  these  bones  being  insured  by  the  two  synovial  membranes. 
The  lower  part  of  the  ring,  formed  by  the  transverse  ligament  with 
the  atlas,  is  smaller  than  the  upper,  while  the  summit  of  the  odontoid 
process  is  larger  than  its  base ;  so  that  the  process  is  still  retained  in 

Fig.  51.  A  posterior  view  of  the  ligaments  connecting  the  alias,  the  axis,  and  the 
occipital  bone.  The  posterior  part  of  the  occipital  bone  has  been  sawn  away,  and  the 
arches  of  the  alias  and  axis  removed.  1.  The  superior  part  of  the  occipito-axoid  liga- 
ment, which  has  been  cut  away  in  order  to  show  the  ligaments  beneath.  2.  The  trans- 
verse ligament  of  the  atlas.  3,  4.  The  ascending  and  descending  slips  of  the  transverse 
ligament,  which  have  obtained  for  it  the  title  of  cruciform  ligament.  5.  One  of  the 
odontoid  ligaments.  6.  One  of  the  occipito-atloid  capsular  ligaments.  7.  One  of  the 
atlo-axoid  capsular  ligaments. 

*  Usually  considered  a  part  of  the  anterior  vertebral  ligament. — G. 

t  These  bands  are  called  the  appendices  of  the  transverse  ligament, — G. 


132  LIGAMENTS  OF  THE  LOWER  JAW. 

its  position  by  the  transverse  ligament,  when  the  other  ligaments  are 
cut  through.  The  extent  to  which  the  rotation  of  the  head  upon  the 
axis  can  be  carried  is  determined  by  the  odontoid  ligaments.  The 
odontoid  process  with  its  ligaments  is  covered  in  by  the  occipito- 
axoid  ligament. 

5.  Jlrticulation  of  the  Lower  Jaw. — The  lower  jaw  has  properly 
but  one  ligament,  the  external  lateral;  the  ligaments  usually  described 
are  three  in  number  ;  to  which  may  be  added,  as  appertaining  to  the 
mechanism  of  the  joint,  an  interarticular  fibro-cartilage,  and  two 
synovial  membranes : — 

External  lateral, 
Internal  lateral. 
Capsular. 

Interarticular  fibro-cartilage. 

Two  synovial  membranes. 

The  external  lateral  ligament  is  a  short  and  thick  band  of  fibres, 
passing  obliquely  forwards  from  the  tubercle  of  the  zygoma,  to  the 

external  surface  of  the  neck  of  the 
F'g-  52.  lower  jaw.     It  is  in  relation,  exter- 

nally with  the  integument  of  the 
face,  and  internally  with  the  syno- 
vial membranes  of  the  articulation, 
and  with  the  interarticular  fibro-car- 
tilage. The  external  lateral  ligament 
acts  conjointly  with  its  fellow  of  the 
opposite  side  of  the  head  in  the  move- 
ments of  the  jaw. 

The  internal  lateral  ligament  has 
no  connexion  with  the  articulation 
of  the  lower  jaw,  and  is  incorrectly 
named  in  relation  to  the  joint;  it  is  a  thin  aponeurotic  expansion, 
extending  from  the  extremity  of  the  spinous  process  of  the  sphenoid 
bone  to  the  margin  of  the  dental  foramen.  It  is  pierced  at  its  inser- 
tion by  the  mylo-hyoidean  nerve. 

A  triangular  space  is  left  between  the  internal  lateral  ligament  and 
the  neck  of  the  jaw,  in  which  are  situated  the  internal  maxillary 
artery  and  auricular  nerve,  the  inferior  dental  artery  and  nerve,  and 
a  part  of  the  external  pterygoid  muscle  ;  internally  it  is  in  relation 
with  the  internal  pterygoid. 

The  capsular  ligament  consists  of  a  few  irregular  ligamentous 
fibres,  which  pass  from  the  edge  of  the  glenoid  cavity  to  the  neck 
of  the  lower  jaw,  upon  the  inner  and  posterior  side  of  the  articula- 

Fig'.  52.  An  external  view  of  the  articulation  of  the  lower  jaw.  1.  The  zygomatic 
arch.  2.  Tlic  tiihorcle  of  the  zyjroma.  .3.  The  ramus  of  the  lower  jaw.  4,  The 
mastoid  portion  of  the  temporal  bone.  5.  The  external  lateral  ligament.  6.  The  stylo- 
maxillary  ligament. 


LIGAMENTS  OF  THE  LOWER  JAW. 


133 


Fig.  54. 


tion.     These  fibres  scarcely  deserve   consideration   as   a  distinct 
ligament. 

The  inter  articular  fibro-cartilage  is  a  thin  oval  plate,  thicker  at 
the  edges  than  in  the  centre,  and  placed  horizontally  between  the 
head   of   the    condyle   of    the 
lower  jaw  and  the  glenoid  ca-  Fig.  53. 

vity.  It  is  connected  b}'-  its 
outer  border  with  the  external 
lateral  ligament,  and  in  front 
receives  some  fibres  of  inser- 
tion of  the  external  pterygoid 
muscles.  Occasionally  it  is  in- 
complete in  the  centre.  It 
divides  the  joint  into  two  dis- 
tinct cavities,  the  one  being 
above  and  the  other  below  the 
cartilage. 

The  synovial  membranes  are  situated  the  one  above,  the  other 
below  the  fibro-cartilage,  the  former  being  the  larger  of  the  two. 
When  the  fibro-cartilage  is  perforate,  the  synovial  membranes  com- 
municate with  each  other. 

Besides  the  lower  jaw,  there  are 
several  other  joints  provided  with  a 
complete  interarticular  fibro-cartilage, 
and  consequently,  with  two  synovial 
membranes;  they  are,  the  sterno-clavi- 
cular  articulation,  the  acromio-clavi- 
cular,  and  the  articulation  of  the  ulna 
with  the  cuneiform  hone. 

The  interarticular  fibro-cartilages 
of  the  knee  joint  are  partial,  and 
there  is  but  one  synovial  membrane. 

The  articulations  of  the  heads  of  the 
ribs  with  the  vertebrae  have  two  syno- 
vial membranes,  separated  by  an  interarticular  ligament  without 
fibro-cartilage. 

Actions. — The  movements  of  the  lower  jaw  are  depression,  by 

Fig.  53.  An  internal  view  of  the  articulation  of  the  lower  jaw.  1.  A  section 
through  the  petrous  portion  of  the  temporal  bone  and  spinous  process  of  the  sphenoid. 
2.  An  internal  view  of  the  ramus,  and  part  of  the  body  of  the  lower  jaw.  3.  The 
internal  portion  of  the  capsular  ligament.  4.  The  internal  lateral  ligament.  5.  A 
small  interval  at  its  insertion  through  which  the  mylo-hyoidean  nerve  passes.  6.  The 
stylo-maxillary  ligament,  a  process  of  the  deep  cervical  fascia. 

Fig.  54.  In  this  sketch  a  section  has  been  carried  through  the  joint,  in  order  to 
show  the  natural  posilion  of  the  interarticular  fibro-cartilage,  and  the  manner  in  which 
it  is  adapted  to  the  difference  of  form  of  the  articulating  surfaces.  1.  The  glenoid 
fossa.  2.  The  eminentia  articularis.  3.  The  interarticular  fibro-cartilage.  4."  Th( 
superior  synovial  cavity.  5.  The  inferior  synovial  cavity.  G.  An  interarticular  fibro 
cartilage,  removed  from  the  joint,  in  order  to  show  its  oval  and  concave  form  ;  it  if 
seen  from  below. 

12 


134  LIGAMENTS  OF  THE  RIBS. 

which  the  mouth  is  opened ;  elevation,  by  which  it  is  closed  ;  2i  far- 
ward  and  backward  movement,  and  a  movement  from  side  to  side. 

In  the  movement  of  depression  the  interarticular  cartilage  glides 
forwards  on  the  eminentia  articularis,  carrying  with  it  the  condyle. 
If  this  movement  be  carried  too  far,  the  superior  synovial  membrane 
is  ruptured,  and  dislocation  of  the  fibro-cartilage  with  its  condyle 
into  the  zygomatic  fossa  occurs.  In  elevation  the  fibro-cartilage 
and  condyle  are  returned  to  their  original  position.  The  forward 
and  backward  movement  is  a  gliding  of  the  fibro-cartilage  upon  the 
glenoid  articular  surface,  in  the  antero-posterior  direction  ;  and  the 
movement  from  side  to  side,  in  the  lateral  direction. 

6.  Articulation  of  the  Ribs  loith  the  Vertebrce. — The  ligaments  of 
these  articulations  are  so  strong  as  to  render  dislocation  impossible, 
the  neck  of  the  rib  would  break  before  displacement  could  occur; 
they  are  divisible  into  two  groups: — 1.  Those  connecting  the  head 
of  the  rib  with  the  vertebrcB ;  and  2.  Those  connecting  the  neck 
and  tubercle  of  the  rib  with  the  transverse  processes.     They  are 

1st  Group. 

Anterior  costo-vertebral  or  stellate, 

Capsular, 

Interarticular  ligament, 

Two  synovial  membranes. 

2d  Group. 

Anterior  costo-transverse, 
Middle  costo-transverse, 
Posterior  costo-transverse. 

The  anterior  costo-vertebral  or  stellate  ligament  (fig.  45)  consists 
of  three  short  bands  of  ligamentous  fibres,  that  radiate  from  the 
anterior  part  of  the  head  of  the  rib.  The  superior  band  passes 
upwards,  and  is  attached  to  the  vertebra  above ;  the  middle  fasci- 
culus is  attached  to  the  intervertebral  substance;  and  the  inferior, 
to  the  vertebra  below. 

In  the  first,  eleventh,  and  tivelfth  ribs,  the  three  fasciculi  are 
attached  to  the  body  of  the  corresponding  vertebra. 

The  capsular  ligament  is  a  thin  layer  of  ligamentous  fibres  sur- 
rounding the  joint  in  the  interval  left  by  the  anterior  ligament;  it  is 
thickest  above  and  below  the  articulation,  and  protects  the  synovial 
membranes. 

The  interarticular  ligament  pstsses  between  the  sharp  crest  on  the 
head  of  the  rib  and  the  intervertebral  substance.  It  divides  the  joint 
into  two  cavities,  which  are  each  furnished  with  a  separate  synovial 
membrane.  The  first,  eleventh,  and  twelfth  ribs  have  no  interarticular 
ligament,  and  consequently  but  one  synovial  membrane. 

The  anterior  costo-transverse  ligament  is  a  broad  band  composed 


LIGAMENTS  OF  THE  RIBS. 


135 


Fig.  55. 


of  several  fasciculi,  which  ascend  from  the  crest  upon  the  neck  of 
the  rib,  to  the  transverse  process  immediately  above.  This  liga- 
ment separates  the  anterior  from  the  posterior  branch  of  the  inter- 
costal nerves. 

The  middle  costo-transverse  ligament  is  a  very  strong  interosseous 
ligament,  passing  directly  between  the  posterior  surface  of  the  neck 
of  the  rib,  and  the  transverse  process  against  which  it  rests. 

The  posterior  costo-transverse  ligament  is  a  small  but  strong  fasci- 
culus, passing  obliquely  from  the  tubercle  of  the  rib,  to  the  apex  of 
the  transverse  process.  The  articulation  between  the  tubercle  of  the 
rib  and  the  transverse  process  is  provided  with  a  small  synovial 
membrane. 

There  is  no  anterior  costo-transverse 
ligament  to  the  first  rib  ;  and  only  rudi- 
mentary posterior  costo-transverse  to  the 
eleventh  and  twelfth  ribs. 

Actions. — The  movements  permitted  by 
the  articulations  of  the  ribs,  are  ujnvards 
and  downwards,  and  slightly /orM)arc?s  and 
hackioards  ;  the  movement  increasing  in 
extent  from  the  head  to  the  extremity  of 
the  rib.  The  forvi^ard  and  backward 
movement  is  very  trifling  in  the  seven 
superior,  but  greater  in  the  inferior  ribs ; 
the  eleventh  and  twelfth  are  very  mo- 
vable. 

7.  Articulation  of  the  Ribs  loith  the  Sternum,  and  tvith  each  other. 
— The  ligaments  of  the  costo-sternal  articulations  are, 

Anterior  costo-sternal. 
Posterior  costo-sternal, 
Superior  costo-sternal, 
Inferior  costo-sternal, 
Synovial  membranes. 

The  anterior  costo-sternal  ligament  is  a  thin  band  of  ligamentous 
fibres,  that  passes  in  a  radiated  direction  from  the  extremity  of  the 
costal  cartilage  to  the  anterior  surface  of  the  sternum,  and  inter- 
mingles its  fibres  with  those  of  the  ligament  of  the  opposite  side, 
and  with  the  tendinous  fibres  of  origin  of  the  pectoralis  major 
muscle. 

The  posterior  costo-sternal  ligament  is  much  smaller  than  the  an- 
terior, and  consists  of  only  a  thin  fasciculus  of  fibres  situated  on  the 
posterior  surface  of  the  articulation. 


Fig.  55.  A  posterior  view  of  a  part  of  the  thoracic  portion  of  the  vertebral  column, 
showing  the  lig-aments  connecting-  the  vertebroe  with  each  other  and  tlie  ribs  with  the 
vertebraR.  1.  The  supra-spinous  ligament.  2,  2.  The  ligamenta  subflava,  connecting 
the  laminsB.  3.  The  anterior  costo-transverse  ligament.  4.  The  posterior  costo-trans- 
verse ligaments. 


136  LIGAMENTS  OF  THE  RIBS. 

The  superior  and  infeinor  costo-sternal  ligaments  are  narrow  fas- 
ciculi corresponding  with  the  breadth  of  the  cartilage,,  and  connect- 
ing its  superior  and  inferior  border  with  the  side  of  the  sternum. 

The  synovial  rnembrane  is  absent  in  the  articulation  of  the  first 
rib,  its  cartilage  being  usually  continuous  with  the  sternum  ;  that  of 
the  second  rib  has  an  inter-articular  ligament,  with  two  synovial 
membranes. 

The  sixth  and  seventh  ribs  have  several  fasciculi  of  strong  liga- 
mentous fibres,  passing  from  the  extremity  of  their  cartilages  to  the 
anterior  surface  of  the  ensiform  cartilage,  which  they  are  intended 
to  support.     They  may  be  named  the  costo-xyphoid  ligaments. 

The  sixth,  seventh,  and  eighth,  and  sometimes  the  fifth  and  the 
ninth  costal  cartilages,  have  articulations  with  each  other,  and  a 
perfect  synovial  membrane.  They  are  connected  by  ligamentous 
fibres  which  pass  from  one  cartilage  to  the  other,  external  and 
internal  ligaments. 

The  ninth  and  tenth  are  connected  at  their  extremities  by  liga- 
mentous fibres,  but  have  no  synovial  membranes. 

Actions. — The  movements  of  the  costo-sternal  articulations  are 
very  trifling;  they  are  limited  to  a  slight  sliding  motion.  The  first 
rib  is  the  least,  and  the  second  the  most  movable. 

8.  Articulation  of  the  Vertebral  Column  with  the  Pelvis. — The  last 
lumbar  vertebra  is  connected  with  the  sacrum  by  the  same  liga- 
ments with  which  ihe  various  vertebra  are  connected  to  each  other  ; 
viz.  the  anterior  and  posterior  common  ligaments,  intervertebral  sub- 
stance, ligamenta  subflava,  capsular  ligaments,  and  inter  and  supra- 
spinous ligaments. 

There  are  only  two  proper  ligaments  connecting  the  vertebral 
column  with  the  pelvis  ;  these  are,  the 

Lumbo-sacral, 
Lumbo-iliac. 

The  lumbosacral  ligament  is  a  thick  triangular  fasciculus  of  liga- 
mentous fibres,  connected  above,  with  the  transverse  process  of  the 
last  lumbar  vertebra;  and  below,  with  the  posterior  part  of  the 
upper  border  of  the  sacrum. 

The  lumbo-iliac  ligament  passes  from  the  apex  of  the  transverse 
process  of  the  last  lumbar  vertebra  to  that  part  of  the  crest  of  the 
ilium  which  surmounts  the  sacro-iliac  articulation.  It  is  triangular 
in  form. 

9.  The  Articulations  of  the  Pelvis. — The  ligaments  belonging  to 
the  articulations  of  the  pelvis  are  divisible  into  four  groups: — 1. 
Those  connecting  the  sacru7n  and  ilium ;  2,  those  passing  between 
the  sacrum  and  ischium;  3,  between  the  sacrum  and  coccyx;  and 
4,  between  the  two  pubic  bones. 

1st,  Between  the  sacrum  and  ilium. 

Sacro-iliac  anterior, 
Sacro-iliac  posterior. 


LIGAMENTS  OF  THE  PELVIS. 


137 


Snd,  Between  the  sacrum  and  ischium. 
Sacro-ischiatic  anterior  (short), 
Sacro-ischiatic  posterior  (long). 

3d,  Betiveen  the  sacrum  and  coccyx. 
Sacro-coccygean  anterior, 
Sacro-coccygean  posterior. 

4th,  Betiveen  the  ossa  'pubis. 
Anterior  pubic, 
Posterior  pubic, 
Superior  pubic. 
Sub-pubic, 
Interosseous  fibro-cartilage. 

1.  Between  the  Sacrum  and  Ilium. — The  anterior  sacra-iliac  liga- 
ment consists  of  numerous  short  ligamentous  fibres,  passing  from 
bone  to  bone  on  the  anterior  surface  of  the  joint. 

The  posterior  sacro-iliac  or  interos-  Fig.  56. 

seous  ligament*  is  composed  of  nume- 
rous strong  fasciculi  of  ligamentous 
fibres,  which  pass  horizontally  be- 
tween the  rough  surfaces,  in  the  pos- 
terior half  of  the  sacro-iliac  articula- 
tion, and  constitute  the  principal 
bond  of  connexion  between  the  sa- 
crum and  the  ilium.  One  fasciculus 
of  this  ligament,  longer  and  larger 
than  the  rest,  is  distinguished,  from 
its  direction,  by  the  name  of  the  ob- 
lique sacro-iliac  ligament.  It  is  at- 
tached by  one  extremity,  to  the  pos- 
terior superior  spine  of  the  ilium ; 
and  by  the  other,  to  the  third  trans- 
verse tubercle  on  the  posterior  sur- 
face of  the  sacrum. 

The  surfaces  of  the  two  bones 
forming  the  sacro-iliac  articulation,  are  partly  covered  with  carti- 
lage, and  partly  rough  and  connected  by  the  interosseous  ligament. 
The  anterior  or  auricvlar  half  is  coaled  with  cartilage,  which  is 
thicker  on  the  sacrum  than  on  the  ilium.  The  surface  of  the  car- 
tilage is  irregular,  and  provided  with  a  very  delicate  synovial  mem- 
Fig.  56.  The  ligaments  of  the  pelvis  and  hip-joint.  1.  The  lower  part  of  the  anterior 
common  ligament  of  the  vertebrc3,  extending  downwards  over  the  front  of  the  sacrum.  2. 
The  lumbo-sacral  ligament.  3.  The  lumbo-iliac  ligament.  4.  The  anterior  sacro-iliac 
ligaments.  5.  The  obturator  membrane.  6.  Poupart's  ligament.  7.  Gimbernat's 
ligament  8.  The  capsular  ligament  of  the  hip-joint.  9.  The  ilro-femoral  or  accessory 
ligament. 

*  This  includes  Horner's  sacro-spinous  ligament. — G. 

12* 


138 


LIGAMENTS  OF  THE  PELVIS. 


brane,  which  cannot  be  demonstrated  in  the  adult ;  but  it  is  apparent 
in  the  young  subject,  and  in  the  female  during  pregnancy. 

2.  Between  the  Sacrum  and  Ischium. — Ihe  anterior  or  lesser  sacro- 
ischiatic  ligament  is  thin,  and  triangular  in  form;  it  is  attached  by 

its  apex  to  the  spine  of  the 
Tig.  57.  ischium  ;  and  by  its  broad  ex- 

tremity to  the  side  of  the  sa- 
crum and  coccyx,  interlacing 
its  fibres  with  the  succeeding. 
The  anterior  sacro-ischiatic 
ligament  is  in  relation  in  front, 
with  the  coccygeus  muscle, 
AW''^  ^    "i^^iVS'l'/  ^^^  behind  with  the  posterior 

il^-^^^''*'~^\  III'     li^hi      >*.  ligament,  with  which  its  fibres 

are  intermingled.  By  its  up- 
per border  it  forms  a  part  of 
the  lower  boundary  of  the 
great  sacro-ischiatic  foramen, 
and  by  the  lower  part  of  the 
lesser  sacro-ischiatic  foramen. 
The  posterior  or  greater  sa- 
cro-ischiatic ligament,  consi- 
derably larger,  thicker,  and 
more  posterior  than  the  pre- 
ceding, is  narrower  in  the  middle  than  at  each  extremity.  It  is 
attached  by  its  smaller  end,  to  the  inner  margin  of  the  tuberosity 
and  ramus  of  the  ischium,  where  it  forms  a  falciform  process,  which 
protects  the  internal  pudic  artery,  and  is  continuous  with  the  ob- 
turator fascia.  By  its  larger  extremity  it  is  inserted  into  the  side  of 
the  coccyx,  sacrum,  and  posterior  inferior  spine  of  the  ilium. 

The  posterior  sacro-ischiatic  ligament  is  in  relation  in  front  with 
the  anterior  ligament,  and  behind  with  the  gluteus  maximus,  to  some 
of  the  fibres  of  which  it  gives  origin.  By  its  superior  border  it 
forms  part  of  the  lesser  ischiatic  foramen,  and  by  its  lower  border, 
a  part  of  the  boundary  of  the  perineum.  It  is  pierced  by  the  coc- 
cygeal branch  of  the  ischiatic  artery.  The  two  ligaments  convert 
the  sacro-ischiatic  notches  into  foramina. 

3.  Belireen  the  Sacrum  and  Coccyx. — The  anterior  sacro-coccy- 
geal  ligament  is  a  thin  fasciculus,  passing  from  the  anterior  surface 
of  the  sacrum  to  the  front  of  the  coccyx. 

The  posterior  sacro-coccygean  ligament  is  a  thick  ligamentous  layer, 

Fig.  57.  Ligaments  of  the  pelvis  and  hip-joint.  The  view  is  taken  from  the  side.  1. 
The  oblirpie  sacro-iliac  ligament.  The  other  fasciculi  of  the  posterior  sacro-iliac  liga- 
ments are  not  seen  in  this  view  of  the  pelvis.  2.  The  posterior  sacro-ischiatic  ligament. 
3.  The  anterior  sacro-ischiatic  ligament.  4.  The  great  sacro-ischiatic  foramen.  5.  The 
lesser  sacro-ischiatic  foramen.  6.  The  cotyloid  ligament  of  the  acetabulum.  7.  The 
ligamentum  teres.  8.  The  cut  edge  of  the  capsular  ligament,  showing  its  extent  pes- 
teriorly  as  compare'd  with  its  anterior  attaclimcnt.  9.  The  obturator  membrane  only 
partly  seen. 


LIGAMENTS  OF  THE  UPPER  EXTREMITY.  139 

v*?hich  completes  the  lower  part  of  the  sacral  canal,  and  connects 
the  sacrum  with  the  coccyx  posteriorly,  extending  as  far  as  the  apex 
of  the  latter  bone. 

Between  the  two  bones  is  a  thin  disc  of  a  soft  intervertebral  sub- 
stance. In  females  there  is  frequently  a  small  synovial  membrane. 
This  articulation  admits  of  a  certain  degree  of  movement  backwards 
during  parturition. 

The  ligaments  connecting  the  different  pieces  of  the  coccyx  con- 
sist of  a  few  scattered  anterior  and  posterior  fibres,  and  a  thin  disc 
of  intervertebral  substance ;  they  exist  only  in  the  young  subject,  in 
the  adult  the  pieces  become  ossified. 

4.  Betiveen  the  Ossa  Pubis. — The  anterior  pubic  ligament  is  com- 
posed of  ligamentous  fibres,  which  pass  obliquely  across  the  union  of 
the  two  bones  from  side  to  side,  and  form  an  interlacement  in  front 
of  the  symphysis. 

The  posterior  pubic  ligament  consists  of  a  few  irregular  fibres 
uniting  the  pubic  bones  posteriorly. 

The  superior  pubic  ligament  is  a  thick  band  of  fibres  connecting 
the  angles  of  the  pubic  bones  superiorly,  and  filling  the  inequalities 
upon  the  surface  of  the  bones. 

The  sub-pubic  ligament  is  a  thick  arch  of  fibres,  connecting  the 
two  bones  inferiorly,  and  forming  the  upper  boundary  of  the  pubic 
arch. 

The  interosseous  fibro-cartilage  unites  the  two  surfaces  of  the  pubic 
bones,  in  the  same  manner  that  the  intervertebral  substance  con- 
nects the  bodies  of  the  vertebrae.  It  resembles  the  intervertebral 
substance  also  in  being  composed  of  oblique  fibres  disposed  in  con- 
centric layers,  which  are  more  dense  towards  the  surface  than  near 
the  centre.  It  is  broad  in  front,  and  narrow  behind.  A  thin  syno- 
vial membrane  is  sometimes  found  in  the  posterior  half  of  the  articu- 
lation. 

This  articulation  becomes  movable  towards  the  latter  term  of  preg- 
nancy, and  admits  of  a  slight  degree  of  separation  of  its  surfaces. 

The  obturator  ligament  or  membrane  is  not  a  ligament  of  articula- 
tion, but  simply  a  tendino-fibrous  membrane  stretched  across  the 
obturator  foramen.  It  gives  attachment  by  its  surfaces,  to  the  two 
obturator  muscles  ;  and  leaves  a  space  in  the  upper  part  of  the  fora- 
men, for  the  passage  of  the  obturator  vessels  and  nerve. 

The  numerous  vacuities  in  the  walls  of  the  pelvis,  and  their  clo- 
sure by  ligamentous  structures,  as  in  the  case  of  the  sacro-ischiatic 
fissures  and  obturator  foramina,  serve  to  diminish  very  materially 
the  pressure  of  the  soft  parts  during  the  passage  of  the  head  of  the 
foetus  through  the  pelvis  in  parturition. 

LIGAMENTS    OF    THE     UPPER     EXTREMITY. 

The  Ligaments  of  the  upper  extremity  may  be  arranged  in  the 
order  of  the  articulation  between  the  different  bones ;  they  are,  the 


140  STERNO-CLAVICULAR  LIGAMENTS. 

1.  Sterno-clavicular  articulation. 

2.  Scapulo-clavacLilar  articulation. 

3.  Ligaments  of  the  scapula. 

4.  Shoulder  joint. 

5.  Elbow  joint. 

6.  Radio-ulnar  articulation. 

7.  Wrist  joint. 

8.  Articulation  between  the  carpal  bones. 

9.  Carpo-metacarpal  articulation. 

10.  Metacarpo-phalangeal  articulation. 

11.  Articulation  of  the  phalanges. 

1.  Sterno-clavicular  Articulation. — The  sterno-clavicular  is  an 
arthrodial  articulation  ;  its  ligaments  are, 

Anterior  sterno-clavicular, 
Posterior  sterno-clavicular, 
Inter-clavicular, 
Costo-clavicular  {rJiomhoid), 

Interarticular  fibro-cartilage, 

Two  synovial  membranes. 

The  anterior  sterno-clavicular  ligament  is  a  broad  ligamentous 
layer,  extending  obliquely  downwards  and  forwards,  and  covering 
the  anterior  aspect  of  the  articulation.  This  ligament  is  in  relation 
by  its  anterior  surface  with  the  integument  and  with  the  sternal 
origin  of  the  sterno-mastoid  muscle;  and  behind  with  the  interarti- 
cular fibro-cartilage  and  synovial  membranes. 

The  posterior  sterno-clavicular  ligament  is  a  broad  fasciculus, 
covering  the  posterior  surface  of  the  articulation.  It  is  in  relation 
by  its  anterior  surface  with  the  interarticular  fibro-cartilage  and 
synovial  membranes,  and  behind  with  the  sterno-hyoid  muscle. 

The  two  ligaments  are  continuous  at  the  upper  and  lower  part 
of  the  articulation,  so  as  to  form  a  complete  capsule  around  the 
joint. 

The  inter-clavicular  ligament  is  a  cord-like  band  which  crosses 
from  the  extremity  of  one  clavicle  to  the  other,  and  is  closely  con- 
nected with  the  upper  border  of  the  sternum.  It  is  separated  by 
cellular  tissue  from  the  sterno-thyroid  muscles. 

The  costo-clavicular  ligament  {rhomboid)  is  a  thick  fasciculus  of 
fibres,  connecting  the  sternal  extremity  of  the  clavicle  with  the 
cartilage  of  the  first  rib.  It  is  situated  obliquely  between  the  rib 
and  the  under  surface  of  the  clavicle.  It  is  in  relation  in  front 
with  the  tendon  of  origin  of  the  subclavius  muscle,  and  behind 
with  the  subclavian  vein. 

Actions. — The  movements  of  the  sterno-clavicular  articulation, 
are  &  gliding  movement  of  the  fibro-cartilage  with  the  clavicle,  upon 
the  articular  surf.ice  of  the  sternum  in  the  direction  forwards, 
backwards,  upwards,  and  downwards  ;  and  circumduction.  This 
articulation  is  the  centre  of  the  movement  of  the  shoulder. 


SCAPULO-CLAVICULAR  LIGAMENTS. 


141 


Fig.  58. 


The   rupture   of  the   rhomboid  ligament  in  dislocation  of  the 
sternal   end  of  the  clavicle,  gives 
rise  to   the   deformity  peculiar   to 
this  accident. 

The  inter  articular  jihro- cartilage 
isnearly  circular  in  form,  and  thicker 
at  the  edges  than  in  the  centre.  It 
is  attached  above,  to  the  clavicle  ; 
below  to  the  cartilage  of  the  first 
rib ;  and  throughout  the  rest  of  its 
circumference  to  the  anterior  and 
posterior  sterno-clavicular  liga- 
ment; it  divides  the  joint  into  two 
cavities,  which  are  lined  by  distinct 

synovial  membranes.  This  cartilage  is  sometimes  pierced  through 
its  centre,  and  not  unfrequently  absorbed  to  a  greater  or  less  extent, 
particularly  at  its  lower  part. 

2.  Scapulo-clavicular  Articulation. — The  ligaments  of  the  scapular 
end  of  the  clavicle  are,  the 

Superior  acromio-clavicular, 
Inferior  acromio-clavicular, 
Coraco-clavicular  {trapezoid  and  conoid), 

Interarticular  fibro-cartilage, 

Two  synovial  membranes. 

The  superior  acromio-clavicular  ligament  is  a  moderately  thick 
plane  of  superimposed  fibres  passing  between  the  extremity  of  the 
clavicle  and  th^  acromion,  upon  the  upper  surface  of  the  joint. 

The  inferior  acromio-clavicular  ligament  is  a  thin  plane  situated 
upon  the  under  surface.  These  two  ligaments  are  continuous  with 
each  other  in  front  and  behind,  and  form  a  complete  capsule  around 
the  joint. 

The  coraco-clavicular  ligament  {trapezoid,  conoid)  is  a  thick  fasci- 
culus of  ligamentous  fibres,  passing  obliquely  between  the  base  of  the 
coracoid  process  and  the  under  surface  of  the  clavicle,  and  holding 
the  end  of  the  clavicle  in  firm  connexion  with  the  scapula.  When 
seen  from  before,  it  has  a  quadrilateral  form :  hence  it  is  named 
trapezoid ;  and,  examined  from  behind,  it  has  a  triangular  form,  the 
base  being  upwards;  hence  another  name,  conoid. 

The  interarticular  fibro-cartilage  is  often  indistinct,  from  having 
partial  connexions  with  the  fibro-cartilaginous  surfaces  of  the  two 
bones  between  which  it  is  placed,  and  not  unfrequently  absent. 
When  partial,  it  occupies  the  upper  part  of  the  articulation.     The 

Fig.  58.  The  ligaments  of  the  pterno-clavicular  and  costo-sternal  articulations.  1. 
The  anterior  sterno-clavicular  ligament.  2.  The  inter-clavicular  ligament.  .3.  The 
costo-clavicular  or  rhomboid  ligament,  seen  on  both  sides.  4.  The  interarticular  fibro- 
cartilage,  brought  into  view  by  the  removal  of  the  anterior  and  posterior  ligaments. 
5.  The  anterior  costo-sternal  ligaments  of  the  first  and  second  ribs. 


143 


SHOULDEK  JOINT. 


Fig.  59. 


synovial  membranes  are  very  delicate.     There  is  only  one,  when  the 
fibro-cartilage  is  incomplete. 

Actions. — The  acromio-clavicular  articulation  admits  of  two  move- 
ments, the  gliding  of  the  surfaces  upon  each  other  ;  and  the  rotation 
of  the  scapula,  upon  the  extremity  of  the  clavicle. 
3.  The  Proper  ligaments  of  the  Scapula  are  the 
Coraco-acromial, 
Transverse. 
The  coraco-acromial  ligament  is  a  broad  and  thick  triangular 
band,  which  forms  a  protecting  arch  over  the  shoulder  joint.     It  is 
attached  by  its  apex  to  the  point  of  the  acromion  process,  and  by 
its  base  to  the  external  border  of  the  coracoid  process  its  whole 
length.     This  ligament  is  in  relation  above  with  the  under  surface 
of  the  deltoid  muscle;  and  below  with  the  tendon  of  the  supra-spi- 
natus  muscle,  a  bursa  mucosa  being  usually  interposed. 

The  transverse  or  coracoid  ligament  is 
a  narrow  but  strong  fasciculus,  which 
crosses  the  notch  in  the  upper  border  of 
the  scapula,  from  the  base  of  the  cora- 
coid process,  and  converts  it  into  a  fora- 
men. The  supra-scapular  nerve  passes 
through  this  foramen. 

4.  Shoulder  joint. — The  scapulo-hume- 
ral  articulation  is  an  enarthrosis,  or  ball 
and  socket  joint — its  hgaments  are,  the 
Capsular, 
Coraco-humeral, 
Glenoid. 
The  capsular  ligament  completely  en- 
circles the  articulating  head  of  the  sca- 
pula and  the  head  of  the  humerus,  and  is 
attached  to  the  neck  of  each  bone.  It  is 
thick  above,  where  resistance  is  most 
required,  and  is  strengthened  by  the  tendons  of  the  supra-spinatus, 
infra-spinatus,  teres  minor,  and  subscapularis  muscles;  below  it  is 
thin  and  loose.  The  capsule  is  incomplete  at  the  point  of  contact 
with  the  tendons,  so  that  they  obtain  upon  their  inner  surface  a 
covering  of  synovial  membrane. 

The  coraco-humeral  ligament  is  a  broad  band  which  descends 
obliquely  outwards  from  the  border  of  the  coracoid  process  to  the 
greater  tuberosity  of  tiie  humerus,  and  serves  to  strengthen  the 
superior  and  anterior  part  of  the  capsular  ligament. 

The  glenoid  ligament  is  the   prismoid  band  of  fibro-cartilage, 

Fig.  59,  The  ligaments  of  the  scapula  find  shoulder  joint.  ] .  The  superior  acro- 
mio-clavicular ligament.  2.  The  coraco-clavicular  ligament;  tiiis  aspect  of  the  liga- 
ment is  named  trapezoid.  3.  The  coraco-acromial  ligament.  4.  The  transverse  liga. 
mcnt.  5.  The  capsular  ligament.  6.  The  coraco-humeral  ligament.  7,  The  long 
tendon  of  the  biceps  issuing  from  the  capsular  ligament,  and  entering  the  bicipital 
groove. 


ELBOW  JOINT.  143 

-which  is  attached  around  the  margin  of  the  glenoid  cavity  for  the 
purpose  of  protecting  its  edges,  and  deepening  its  cavity.  It  divides 
superiorly  into  two  slips  which  are  continuous  with  the  long  tendon 
of  the  biceps ;  hence  the  ligament  is  frequently  described  as  being 
formed  by  the  splitting  of  that  tendon.  The  cavity  of  the  articu- 
lation is  traversed  by  the  long  tendon  of  the  biceps,  which  is 
enclosed  in  a  sheath  of  synovial  membrane  in  its  passage  through 
the  joint. 

The  synovial  membrane  of  the  shoulder  joint  is  very  extensive  ;  it 
communicates  anteriorly  through  an  opening  into  the  capsular  liga- 
ment wiih  a  large  bursal  sac,  which  lines  the  under  surface  of  the 
tendon  of  the  subscapularis  muscle.  Superiorly,  it  frequently  com- 
municates through  another  opening  in  the  capsular  ligament  with 
a  bursal  sac  belonging  to  the  infra-spinatus  muscle ;  and  it  more- 
over forms  a  sheath  around  that  portion  of  the  tendon  of  the  biceps, 
which  is  included  within  the  joint. 

The  muscles  immediately  surrounding  the  shoulder  joint  are  the 
subscapularis,  supra-spinatus,  infra-spinatus,  teres  minor,  long  head 
of  the  triceps,  and  deltoid  ;  the  long  tendon  of  the  biceps  is  within 
the  capsular  ligament. 

Actions. — The  shoulder  joint  is  capable  of  every  variety  of  motion, 
viz.  of  movement  forwards  and  backwarks,  of  abduction,  and  adduc- 
tion, of  circumduction  and  rotation. 

5.  ElboiD  Joint. — The  elbow  is  a  ginglymoid  articulation;  its 
ligaments  are  four  in  number: 

Anterior, 
Posterior, 
Internal  lateral, 
External  lateral. 

The  anterior  ligament  is  a  broad  and  thin  membranous  layer, 
descending  from  the  anterior  surface  of  the  humerus,  immediately 
above  the  joint,  to  the  coronoid  process  of  the  ulna  and  orbicular 
ligament.  On  each  side  it  is  connected  v;ith  the  lateral  ligaments. 
It  is  composed  of  fibres  which  pass  in  three  different  directions, 
vertical,  transverse,  and  oblique,  the  latter  being  extended  from 
within  outwards  to  the  orbicular  ligament,  into  which  they  are 
attached  inferiorly.  This  ligament  is  covered  in  by  the  brachialis 
anticus  muscle. 

The  posterior  ligarnent  is  a  broad  and  loose  fold,  passing  between 
the  posterior  surface  of  the  humerus  and  the  anterior  surface  of  the 
base  of  the  olecranon,  and  connected  at  each  side  with  the  lateral 
ligaments.     It  is  covered  in  by  the  tendon  of  the  triceps.. 

The  internal  lateral  ligament  is  a  thick  triangular  layer,  attached 
above,  by  its  apex,  to  the  internal  condyle  of  the  humerus ;  and 
below,  by  its  expanded  border,  to  the  margin  of  the  greater  sig- 
moid cavity  of  the  ulna,  extending  from  the  coronoid  process  to 
the  olecranon.     At  its  insertion  it  is  intermingled  with  some  trans- 


144 


ELBOW  JOINT. 


verse  fibres.     The  internal  lateral  ligament  is  in  relation  posteriorly 
with  the  ulnar  nerve. 


Fijr.  60. 


Fig.  61. 


The  external  lateral  ligament  is  a  strong  and  narrow  band,  which 
descends  from  the  external  condyle  of  the  humerus,  to  be  inserted 
into  the  orbicular  ligament,  and  into  the  ridge  on  the  ulna,  witfi 
which  the  posterior  part  of  the  lateral  ligament  is  connected.  This 
ligament  is  closely  united  with  the  tendon  of  origin  of  the  supinator 
brevis  muscle. 

The  synovial  membrane  is  extensive,  and  is  reflected  from  the 
cartilaginous  surfaces  of  the  bones  upon  the  inner  surface  of  the 
ligaments.  It  surrounds  inferiorly  the  head  of  the  radius,  and 
forms  an  articulating  sac  between  it  and  the  lesser  sigmoid  notch. 

The  muscles  immediately  surrounding,  and  in  contact  with,  the 
elbow  joint,  are  in  front,  the  brachialis  anticus  ;  to  the  inner  side, 
the  pronator  radii  teres,  flexor  sublimis  digitorum,  and  flexor  carpi 
ulnaris ;  externally,  the   extensor  carpi   radialis   brevior,  extensor 

Fig.  60.  An  internal  view  of  the  ligaments  of  the  elbow  joint.  1.  The  anterior  liga- 
ment. 2.  The  internal  lateral  ligament.  3.  The  orbicular  ligament.  4.  The  oblique 
ligament.  5.  1'he  interosseous  ligament.  6.  The  intOTlal  condyle  of  the  humerus, 
which  conceals  the  posterior  ligament. 

Fig.  61.  An  external  view  of  the  elbow  joint.,  1.  The  humerus.  2.  The  ulna.  3. 
The  radius.  4.  The  external  lateral  ligament  inserted  inferiorly  into  (.5)  the  orbicular 
ligament.  6.  The  posterior  extremity  of  the  orbicular  ligament  spreading  out  at  its 
insertion  into  the  ulna.  7.  The  anterior  ligament,  scarcely  apparent  in  this  view  of 
the  articulation.  8.  The  posterior  ligament,  thrown. into  folds  by  the  extension  of  the 
joint. 


ELBOW  JOINT. 


145 


Fig.  62. 


communis  digitorum,  extensor  carpi  ulnaris,  anconeus,  and  supi- 
nator brevis ;  and  behind,  the  triceps. 

Actions. — The  movements  of  the  elbow-joint  are  Jlexion  and 
extension,  which  are  performed  with  remarkable  precision.  The 
extent  to  which  these  movements  are  capable  of  being  effected,  is 
limited,  in  front  by  the  coronoid  process,  and  behind  by  the  ole- 
cranon. 

6.  The  R0io-ulnar  Articulation. — The  radius  and  ulna  are  firmly 
held  together  by  ligaments  which  are  connected  with  both  extre- 
mities of  the  bones,  and  with  the  shaft;  they  are,  the 

Orbicular,  Anterior  inferior. 

Oblique,  Posterior  inferior, 

Interosseous,  Interarticular  fibro-cartilage. 

The  orbicular  ligament  {annular,  coronary)  is  a  firm  band  several 
lines  in  breadth,  which  surrounds  the  head  of  the  radius,  and  is 
attached  by  each  end  to  the  extremities  of  the  lesser  sigmoid  cavity. 
It  is  strongest  behind  where  it  receives  the  ex- 
ternal lateral  ligament,  and  is  lined  on  its  inner 
surface  by  a  reflection  of  the  synovial  membrane 
of  the  elbow  joint. 

The  rupture  of  this  ligament  permits  of  the 
dislocation  of  the  head  of  the  radius. 

The  oblique  ligament  is  a  narrow  slip  of  liga- 
mentous fibres,  descending  obliquely  from  the 
base  of  the  coronoid  process  of  the  ulna  to  the 
lower  part  of  the  tuberosity  of  the  radius. 

The  interosseous  ligament  is  a  broad  and  thin 
plane  of  aponeurotic  fibres,  passing  obliquely 
downwards  from  the  sharp  ridge  on  the  radius 
to  that  on  the  ulna.  It  is  deficient  superiorly,  is 
broader  in  the  middle  than  at  each  extremity, 
and  is  perforated  at  its  lower  part  for  the  pas- 
sage of  the  anterior  interosseous  jirtery.  The 
posterior  interosseous  artery  passes  backwards  between  the  oblique 
ligament  and  the  upper  border  of  the  interosseous  ligament.  This 
ligament  aflfords  an  extensive  surface  for  the  attachment  of  muscles. 

The  interosseous  ligament  is  in  relation,  in  front,  with  the  flexor 
profundus  digitorum,  the  flexor  longus  polJicis,  and  pronator  quad- 
ratus  muscle,  and  with  the  anterior  interosseous  artery  and  nerve, 
and  behind  with  the  supinator  brevis,  extensor  ossis  metacarpi 
pollicis,  extensor  primi  internodii  pollicis,  extensor  secundi  inter- 
nodii  pollicis,  and  extenspr  indicis  muscle,  and  near  the  wrist  with 
the  anterior  interosseous  artery  and  posterior  interosseous  nerve. 

The  anterior  inferior  ligament  is  a  thin  fasciculus  of  fibres,  passing 
transversely  between  the  radius  and  ulna. 

Fig.  62.  1.  Articular  surface  of  olecranon  process  of  the  ulna.  2.  Coronoid  process. 
3.  Orbicular  ligament  surrounding  the  neck  of  the  radius. 

13 


146 


CARPAL  ARTICULATIONS. 


Fig.  63. 


The  posterior  inferior  ligament  is  also  thin  and  loose,  and  has  the 
same  disposition  on  the  posterior  surface  of  the  articulation. 

The  inter  articular,  or  triangular  ^hro-cartilage,  acts  the  part  of  a 
ligament  between  the  lower  extremities  of  the  radius  and  ulna.  It 
is  attached  by  its  apex  to  a  depression  on  the  inner  surface  of  the 
styloid  process  of  the  ulna,  and  by  its  base  to  the  edge  of  the  radius. 
This  fibro-cartilage  is  lined  upon  its  upper  surface  by  a  synovial 
membrane,  which  forms  a  duplicature  between  the  radius  and  ulna, 
and  is  called  the  memhrana  sacciformis.  By  its  lower  surface  it 
enters  into  the  articulation  of  the  wrist  joint. 

Actions. — The  movements  taking  place 
between  the  radius  and  the  ulna,  are  the 
rotation  of  the  former  upon  the  latter; 
rotation  forwards  being  termed  pronation, 
and  rotation  backwards  supination.  In 
these  movements  the  head  of  the  radius 
turns  upon  its  own  axis,  within  the  orbicu- 
lar ligament  and  the  lesser  sigmoid  notch 
of  the  ulna ;  while  inferiorly  the  radius 
presents  a  concavity  which  moves  upon 
the  rounded  head  of  the  ulna.  The 
movements  of  the  radius  are  chiefly 
limited  by  the  anterior  and  posterior  in- 
ferior ligaments,  hence  these  are  not  un- 
frequently  ruptured  in  great  muscular 
efforts. 

7.  JVi'ist  Joint. — The  wrist  is  a  gingly- 
moid  articulation;  the  articular  surfaces 
entering  into  its  formation  being  the  ra- 
dius and  under  surface  of  the  triangular 
fibro-cartilage  above,  and  the  rounded 
surfaces  of  the  scaphoid,  semilunar,  and 
cuneiform  bone  below  ;  its  ligaments  are 
four  in  number. 
Anterior,  Internal  lateral. 

Posterior,  External  lateral. 


Fig.  63.  The  ligaments  of  the  anterior  aspect  of  the  wrist  and  hand.  1.  The  lower 
part  of  the  interosseous  membrane.  2.  The  anterior  inferior  radio-ulnar  ligament.  3. 
The  anterior  ligament  of  the  wrist  joint.  4.  Its  extoinal  lateral  ligament.  5.  lis  in- 
ternal lateral  ligament.  6.  The  palmar  ligaments  of  the  carpus.  7.  The  pisiform 
bone,  with  its  ligaments.  8.  The  ligaments  connecting  the  second  ranjre  of  carpal 
bones  with  the  metacarpal,  and  the  metacarpal  with  each  olher.  9.  Tlie  capsular 
ligament  of  the  carpo-metacarpal  articulation  of  the  tiiumb.  10.  Anterior  ligament 
of  the  metacarpo-phalangeal  articulation  of  the  thumb.  11.  One  of  the  lateral  liga- 
ments of  that  articulation.  12.  Anterior  ligament  of  the  metacarpophalangeal  arti- 
culation of  the  index  finger;  these  ligaments  have  been  removed  in  the  other  fingers. 
13.  Lateral  ligaments  of  the  same  articulation  ;  the  corresponding  ligaments  are  seen 
in  the  other  articulations.  14.  Transverse  ligament  connecting  liie  heads  of  the 
metacarpal  hones  of  the  index  and  middle  fingers  ;  the  same  ligament  is  .seen  between 
the  other  fingers.  15.  Anterior  and  one  lateral  ligament  of  the  phalangeal  articula- 
lion  of  the  thumb.  16.  Anterior  and  lateral  ligaments  of  the  phalangeal  articulations 
of  the  index  finger ;  the  anterior  ligaments  are  removed  in  the  other  fingers. 


WRIST  JOINT.  147 

The  anterior  ligament  is  a  broad  and  membranous  layer  consist- 
ing of  three  fasciculi,  which  pass  between  the  lower  part  of  the 
radius,  and  the  scaphoid,  semilunar,  and  cuneiform  bones. 

The  posterior  ligament,  also  thin  and  loose,  passes  between  the 
posterior  surface  of  the  radius,  and  the  posterior  surface  of  the 
semilunar  and  cuneiform  bones. 

The  internal  lateral  ligament  extends  from  the  styloid  process  of 
the  ulna  to  the  cuneiform  and  pisiform  bone. 

The  external  lateral  ligament  is  attached  by  one  extremity  to  the 
styloid  process  of  the  radius,  and  by  the  other  to  the  side  of  the 
scaphoid  bone.  The  radial  artery  rests  on  this  ligament  as  it  passes 
backwards  to  the  first  metacarpal  space. 

The  synovial  membrane  of  the  wrist  joint  lines  the  under  surface 
of  the  radius  and  interarticular  fibro-cartilage  above,  and  the  first 
row  of  bones  of  the  carpus  below. 

The  relations  of  the  wrist  joint  are  the  flexor  and  extensor  ten- 
dons by  which  it  is  surrounded,  and  the  radial  and  ulnar  artery. 

Actions. — The  movements  of  the  wrist  joint  Q.YeJlexion,  extension, 
adduction,  abduction,  and  circumduction.  In  these  motions  the  arti- 
cular surfaces  glide  upon  each  other. 

.Articulations  between  the  Carpal  bones. — These  are  amphi-arthro- 
dial  joints,  with  the  exception  of  the  conjoined  head  of  the  os  mag- 
num and  unciforme,  which  is  received  into  a  cup  formed  by  the 
scaphoid,  semilunar,  and  cuneiform  bones,  and  constitutes  an  enar- 
throsis.     The  ligaments  are, 

Dorsal, 
Palmar, 
Interosseous, 
Anterior  annular. 

The  dorsal  ligaments,  are  ligamentous  bands,  that  pass  from  bone 
to  bone  in  every  direction,  upon  the  dorsal  surface  of  the  carpus. 

The  palmar  ligaments  are  fasciculi  of  the  same  kind,  but 
stronger  than  the  dorsal,  having  the  like  disposition  upon  the  palmar 
surface. 

The  interosseous  ligaments  are  situated  between  the  adjoining 
bones  in  each  range  :  in  the  upper  range  they  close  the  upper 
part  of  the  spaces  between  the  scaphoid,  semilunar,  and  cuneiform 
bones;  in  the  lower  range  they  are  stronger  than  in  the  upper,  and 
connect  the  os  magnum  on  the  one  side  to  the  unciforme,  on  the 
other  to  the  trapezoides,  and  leave  intervals  through  which  the 
synovial  membrane  is  continued  to  the  bases  of  the  metacarpal 
bones. 

The  anterior  annular  ligament  is  a  firm  ligamentous  band,  which 
cohnects  the  bones  of  the  two  sides  of  the  carpus.  It  is  attached 
by  one  extremity  to  the  trapezium  and  scaphoid,  and  by  the  other 
to  the  unciform  process  of  the  unciforme  and  the  base  of  the  pisi- 
form bone,  and  forms  an  arch  over  the  anterior  surface  of  the 


149 


CARPO-METACARPAL  ARTICULATION. 


Fig.  64. 


carpus,  beneath  which  the  tendons  of  the  long  flexors  and  the 
median  nerve  pass  into  the  palm  of  the  hand. 

The  articulation  of  the  pisiform  bone  with  the  cuneiform,  is  pro- 
vided with  a  distinct  synovial  membrane,  which  is  protected  by- 
fasciculi  of  ligamentous  fibres,  forming  a  kind  of  capsule  around  the 
joint ;  they  are  inserted  into  the  cuneiforme,  unciforme  and  base  of 
the  metacarpal  bone  of  the  little  finger. 

Synovial  membranes. — There  are  five  synovial  membranes  enter- 
ing into  the  composition  of  the  articulations  of  the  carpus  : 

The  first  is  situated  between  the  lower  end  of  the  ulna  and  the 
interarticular  fibro-cartilage ;  it  is  called  sacciform,  from  forming 

a  sacculus  between  the  lateral  articu- 
lation of  the  ulna  with  the  radius. 

The  second  is  situated  between  the 
lower  surface  of  the  radius  and  inter- 
articular fibro-cartilage  above,  and  the 
first  range  of  bones  of  the  carpus 
beloiv. 

The  third  is  the  most  extensive  of 
the  synovial  membranes  of  the  wrist ; 
it  is  situated  between  the  two  rows  of 
carpal  bones,  and  passes  between  the 
bones  of  the  second  range  to  invest 
the  carpal  extremities  of  the  four  meta- 
carpal bones  of  the  fingers. 

The  fourth  is  the  synovial  membrane 

of  the  articulation  of  the  metacarpal 

bone  of  the  thumb  with  the  trapezium. 

The  fifth  is   situated   between   the 

pisiform  and  cuneiform  bone. 

Actions. — Very  little  movement  exists  between  the  bones  in  each 

range,  but  more  is  permitted  between  the  two  ranges.    The  motions 

in  the  latter  situation  are  those  of  flexion  and  extension. 

9.  The  Carpo-metacarpal  Articulation. — The  second  row  of 
bones  of  the  carpus  articulates  with  the  metacarpal  bones  of  the 
four  fingers  by  dorsal  and  palmar  ligaments  ;  and  the  metacarpal 
bone  of  the  thumb  with  the  trapezium  by  a  true  capsular  ligament. 
The  dorsal  ligaments  are  strong  fasciculi  which  pass  from  the 
second  range  of  carpal  to  the  metacarpal  bones. 

Fij|r.  64.  A  diafjram  showing  the  disposition  of  the  five  synovial  membranes  of  the 
wrist  joint.  1.  The  sacciform  membrane.  2.  The  second  synovial  membrane.  3,3. 
The  third,  or  large  synovial  membrane.  4.  The  synovial  membrane  between  the  pisi- 
form bone  and  the  cuneiforme.  5.  The  synovial  membrane  of  the  metacarpal  articu- 
lation of  llie  thumb.  6.  Tiie  lower  extremity  of  the  radius.  7.  The  lower  extremity 
of  the  ulna.  8.  The  interarticular  fibro-cartilage.  S.  The  scaphoid  bone.  L.  The 
scmilunare.  C.  The  cuneiforme  ;  the  interosseous  ligaments  are  seen  passing  between 
these  three  bones  and  separating  tlie  articulation  of  the  wrist  (2)  from  the  articulation 
of  the  carpal  bones  (3).  /•*.  The  pisiforme.  T.  The  trapezium.  T.  The  trape- 
zoides.  M.  The  os  magnum.  U.  'i'hc  unciforme  ;  intcnisscous  ligaments  are  seen 
connecting  the  os  magnum  with  the  trapezuides  and  unciforme.  9.  The  base  of  the 
metacarpal  bone  of  the  thumb.     10,  10.  The  bases  of  the  other  metacarpal  bones. 


METACARPO-JPHALANGEAL  ARTICULATION.  1  49 

The  palmar  ligaments  are  thin  fasciculi  arranged  upon  the  same 
plan  on  the  palmar  surface. 

The  synovial  membrane  is  a  continuation  of  the  great  synovial 
membrane  of  the  two  rows  of  carpal  bones. 

The  capsular  ligament  of  the  thumb  is  one  of  the  three  true  cap- 
sular ligaments  of  the  skeleton ;  the  other  two  being  the  shoulder- 
joint  and  hip-joint.  The  articulation  has  a  proper  synovial  mem- 
brane. 

The  metacarpal  bones  of  the  four  fingers  are  firmly  connected  at 
their  bases  by  means  of  dorsal  and  palmar  ligaments,  which  extend 
transversely  from  one  bone  to  the  other,  and  by  interosseous  liga- 
ments which  pass  between  their  contiguous  surfaces.  Their  lateral 
articular  facets  are  lined  by  a  reflection  of  the  great  synovial  mem- 
brane of  the  two  rows  of  carpal  bones. 

Actions. — The  movements  of  the  metacarpal  on  the  carpal  bones, 
are  restricted  to  a  slight  degree  of  sliding  motion,  with  the  excep- 
tion of  the  articulation  of  the  metacarpal  bone  of  the  thumb  with 
the  trapezium.  In  the  latter  articulation,  the  movements  are, 
Jiexion,  extension,  adduction,  abduction,  and  circumduction. 

10.  Metacarpo-phalangeal  Articulation. — The  metacarpo-phalan- 
geal  articulation  is  a  ginglymoid  joint :  its  ligaments  are  four  in 
number. 

Anterior, 
Two  lateral, 
Transverse. 

The  anterior  ligaments  are  thick  and  fibro-cartilaginous,  and  form 
part  of  the  articulating  surface  of  the  joints.  They  are  grooved 
externally  for  the  lodgment  of  the  flexor  tendons,  and  by  their 
internal  aspect  form  part  of  the  articular  surface  for  the  head  of  the 
metacarpal  bone. 

The  lateral  ligaments  are  strong  narrow  fasciculi,  holding  the 
bones  together  at  each  side. 

The  transverse  ligaments  are  strong  ligamentous  bands  passing 
between  the  anterior  ligaments,  and  connecting  together  the  heads 
of  the  metacarpal  bones  of  the  four  fingers. 

The  expansion  of  the  extensor  tendon  over  the  back  of  the  fingers 
takes  the  place  of  a  posterior  ligament. 

Actions. — This  articulation  admits  of  movement  in  four  different 
directions,  viz.  oi  Jiexion,  extension,  adduction  and  abduction,  the 
two  latter  being  limited  to  a  small  extent.  It  is  also  capable  of  cir- 
cumduction. 

11.  Articulation  of  the  Phalanges. — These  articulations  are  gingly- 
moid joints:  they  are  formed  by  three  ligaments. 

Anterior, 
Two  lateral. 

The  anterior  ligament  is  firm  and  fibro-cartilaginous,  and  forms 

13* 


150  HIP  JOINT. 

part  of  the  articular  surface  for  the  head  of  the  phalanges.  Exter- 
nally it  is  grooved  for  the  reception  of  the  flexor  tendons. 

The  lateral  ligaments  are  very  strong ;  they  are  the  principal 
bond  of  connexion  between  the  bones. 

The  extensor  tendon  takes  the  place  and  performs  the  office  of  a 
posterior  ligament. 

Actions, — The  movements  of  the  phalangeal  joints  d^re  flexion  and 
extension,  these  movements  being  more  extensive  between  the  first 
and  second  phalanges  than  between  the  second  and  third. 

LIGAMENTS    OF    THE    LOWER    EXTREMITY. 

The  ligaments  of  the  lower  extremity,  like  those  of  the  upper,  may 
be  arranged  in  the  order  of  the  joints  to  which  they  belong ;  these 
are,  the 

1.  Hip  joint. 

2.  Knee  joint. 

3.  Articulation  between  the  tibia  and  fibula. 

4.  Ankle  joint. 

5.  Articulation  of  the  tarsal  bones. 

6.  Tarso-metatarsal  articulation. 

7.  Metatarso-phalangeal  articulation. 

8.  Articulation  of  the  phalanges. 

1.  Hip  Joint. — The  articulation  of  the  head  of  the  femur  with  the 
acetabulum  constitutes  an  enarthrosis,  or  ball  and  socket  joint. 
The  articular  surfaces  are  the  cup-shaped  cavity  of  the  acetabulum 
and  the  rounded  head  of  the  femur;  the  ligaments  are  five  in 
number,  viz: : 

Capsular, 

Ilio-femoral, 

Teres, 

Cotyloid, 

Transverse. 

The  capsular  ligament  (fig.  56,  8)  is  a  strong  ligamentous  cap- 
sule, embracing  the  acetabulum  superiorly,  and  inferiorly  the  neck 
of  the  femur,  and  connecting  the  two  bones  firmly  together.  It  is 
much  thicker  upon  the  upper  part  of  the  joint,  where  more  resist- 
ance is  required,  than  upon  the  under  part,  and  extends  farther  upon 
the  neck  of  the  femur  on  the  anterior  and  superior  than  on  the  pos- 
terior and  inferior  side,  being  attached  to  the  intertrochanteric  line 
in  front,  to  the  base  of  the  great  trochanter  above,  and  to  the  middle 
of  the  neck  of  the  femur  behind. 

The  ilio-femaral  ligament*  (fig.  56, 9)  is  an  accessory  and  radiating 
band,  which  descends  obliquely  from  the  anterior  inferior  spinous 

*  Called  also  ligamentvm  adacititium, — G. 


KNEE  JOINT.  151 

process   of  the   ilium  to   the   anterior  intertrochanteric  line,  and 
strengthens  the  anterior  portion  of  the  capsular  ligament. 

The  ligamentum  teres  (fig.  57,  7),  triangular  in  shape,  is  attached 
by  a  rounded  apex  to  the  depression  just  below  the  middle  of  the 
head  of  the  femur,  and  by  its  base,  which  divides  into  two  fasciculi, 
into  the  borders  of  the  notch  of  the  acetabulum.  It  is  formed  by  a 
fasciculus  of  fibres  of  variable  size,  surrounded  by  synovial  mem- 
brane ;  sometimes  the  synovial  membrane  alone  exists,  or  the  liga- 
ment is  wholly  absent. 

The  cotyloid  ligament  (fig.  57,  7)  is  a  prismoid  cord  of  fibro-car- 
tilage,  attached  around  the  margin  of  the  acetabulum,  and  serving 
to  deepen  the  cavity  and  protect  its  edges.  It  is  much  thicker  upon 
the  upper  and  outer  border  of  the  acetabulum  than  in  front,  and 
consists  of  fibres  which  arise  from  the  whole  circumference  of  the 
brim,  and  interlace  with  each  other  at  acute  angles. 

The  transverse  ligament  is  a  strong  fasciculus  of  ligamentous 
fibres,  continuous  with  the  cotyloid  ligament,  and  extended  across 
the  notch  in  the  acetabulum.  It  converts  the  notch  into  a  foramen, 
through  which  the  articular  branches  of  the  internal  circumflex  and 
obturator  arteries  enter  the  joint. 

The  fossa  at  the  bottom  of  the  acetabulum  is  filled  by  a  mass  of 
fat,  covered  with  synovial  membrane,  which  serves  as  an  elastic 
cushion  to  the  head  of  the  bone  during  its  movements.  This  was 
considered  by  Havers  as  the  synovial  gland. 

The  synovial  membrane  is  extensive;  it  invests  the  head  of  the 
femur,  and  is  continued  around  the  ligamentum  teres  into  the  ace- 
tabulum ;  it  is  thence  reflected  upon  the  inner  surface  of  the  cap- 
sular ligament. 

The  muscles  immediately  surrounding  and  in  contact  with  the 
hip  joint  are,  in  front,  the  psoas  and  iliacus,  which  are  separated 
from  the  capsular  ligament  by  a  large  synovial  bursa  ;  above, 
the  short  head  of  the  rectus,  and  the  gluteus  minimus ;  behind,  the 
pyriformis,  gemellus  superior,  obturator  internus,  gemellus  inferior, 
and  quadratus  femoris ;  and  to  the  inner  side,  the  obturator  externus 
and  pectineus. 

Actions. — The  movements  of  the  hip  joint  are  very  extensive ; 
they' are  flexion,  extension,  adduction,  abduction,  circumduction,  and 
rotation. 

2.  Knee  Joint. — The  knee  is  a  ginglymoid  articulation  of  a  large 
size,  and  is  provided  with  numerous  ligaments ;  they  are  thirteen  in 
number. 

Anterior  or  ligamentum  patellae, 

Posterior  or  ligamentum  posticum  Winslowi, 

Internal  lateral. 

Two  external  lateral. 

Anterior  or  external  crucial. 

Posterior  or  internal  crucial, 

Transverse, 


152  KNEE  JOINT. 


Two  coronary, 


false. 


Ligamentum  mucosum, 
Ligamenta  alaria, 

Two  semilunar  fibro-cartilages, 

Synovial  membrane. 


The  five  first  are  external  to  the  articulation  ;  the  five  next  are 
internal  to  the  articulation ;  the  three  remaining  are  mere  folds  of 
synovial  membrane,  and  have  no  title  to  the  name  of  ligaments.  In 
addition  to  the  ligaments,  there  are  two  fibro-cartilages,  which  are 
sometimes  very  erroneously  considered  among  the  ligaments  ;  and 
a  synovial  membrane,  which  is  still  more  improperly  named  the 
capsular  ligament. 

The  anterior  ligament  or  ligamentum  patellce,  is  the  prolongation 
of  the  tendon  of  the  extensor  muscles  of  the  thigh  downwards  to  the 
tubercle  of  the  tibia.  It  is,  therefore,  no  ligament ;  and,  as  we  have 
before  stated,  that  the  patella  is  simply  a  sesamoid  bone,  developed 
in  the  tendon  of  the  extensor  muscles  for  the  defence  of  the  front  of 
the  knee  joint,  it  has  no  title  to  consideration,  either  as  a  ligament 
of  the  knee  joint  or  as  a  ligament  of  the  patella. 

A  small  bursa  mucosa  is  situated  between  the 
Fig-.  65.  ligamentum  patellae,  near  to  its  insertion,  and  the 

front  of  the  tibia,  and  another  of  larger  size  is 
placed  between  the  patella  and  the  fascia  lata, 
which  extends  over  its  anterior  surface. 

The  posterior  ligament — ligamentum  posticum 
Winslowi,* — is  a  broad  expansion  of  ligamentous 
fibres,  which  covers  the  whole  of  the  posterior 
part  of  the  joint.  It  is  divisible  into  two  lateral 
portions,  which  invest  the  condyles  of  the  femur, 
and  a  central  portion,  which  is  depressed  and 
formed  by  the  interlacement  of  fasciculi  passing 
in  different  directions.  The  strongest  of  these  fasci- 
culi is  that  which  is  derived  from  the  tendon  of  the 
semimembranosus,  and  passes  obliquely  upwards 
and  outwards,  from  the  posterior  part  of  the  inner 
tuberosity  of  the  tibia  to  the  external  condyle.  Other  accessory 
fasciculi  are  given  off  by  the  tendon  of  the  poplitcus  and  by  the 
heads  of  the  gastrocnemius.  Tfie  middle  portion  of  the  ligament 
supports  the  popliteal  artery  and  vein,  and  is  perforated  by  several 

Figf.  65.  The  anterior  view  of  the  ligaments  of  the  knee-joint.  1.  The  tendon  of  the 
quadriceps  extensor  muscle  of  the  leg.  2.  The  patella.  3.  The  anterior  ligament,  or 
liganienlum  patellae,  near  its  insertion.  4,  4.  The  synovial  membrane.  5.  The  internal 
lateral  ligament.  6.  The  long  external  lateral  ligament.  7.  The  anterior  superior 
tibio-fibular  ligament. 

*  In  a  recent  dissection  in  Sydenham  College,  Mr.  Joseph  Chapman  observed  a  small 
fleshy  muscle,  connected  by  one  extremity  with  the  external  condyle  of  the  femur,  and 
inserted  by  the  other  into  that  portion  of  this  ligament  which  is  derived  from  the  tendon 
of  the  semimembranosus. 


KNEE  JOINT. 


153 


Fig.  66. 


openings  for  the  passage  of  branches  of  the  azygos  articular  artery, 
and  for  the  nerves  of  the  joint. 

The  internal  lateral  ligament  is  a  broad  and  trapezoid  layer  of 
ligamentous  fibres,  attached  above  to  the  tubercle  on  the  internal 
condyle  of  the  femur,  and  below  to  the  side  of  the  inner  tuberosity 
of  the  tibia.  It  is  crossed  at  its  lower  part  by  the  tendons  of  the 
inner  hamstring,  from  which  it  is  separated  by  a  synovial  bursa,  and 
it  covers  in  the  anterior  slip  of  the  semi-membranosus  tendon  and 
the  inferior  internal  articular  artery. 

External  lateral  ligaments. — The  long  external  lateral  ligament  is 
a  strong  rounded  cord,  which  descends  from  the  posterior  part  of 
the  tubercle  upon  the  external  condyle  of  the  femur  to  the  outer 
part  of  the  head  of  the  fibula.  The  short  external  lateral  ligament 
is  an  irregular  fasciculus  situated  behind  the  pre- 
ceding, arising  from  the  external  condyle  near 
the  origin  of  the  head  of  the  gastrocnemius 
muscle,  and  inserted  into  the  posterior  part  of 
the  head  of  the  fibula.  It  is  firmly  connected 
with  the  external  semilunar  fibro-cartilage,  and 
appears  principally  intended  to  connect  that 
cartilage  with  the  fibula.  The  long  external 
lateral  ligament  is  covered  in  by  the  tendon  of 
the  biceps,  and  has  passing  beneath  it  the  tendon 
of  the  origin  of  the  popliteus  muscle,  and  the  in- 
ferior external  articular  artery. 

The  true  ligaments  loithin  the  joint  are  the 
crucial,  transverse  and  coronary. 

The    anterior  or  external   crucial  ligament, 
arises  from  the  depression  upon  the  head  of  the 
tibia  in  front  of  the  spinous  process,  and  passes  upwards  and  back- 
wards to  be  inserted  into  the  inner  surface  of  the  outer  condyle  of 
the  femur,  as  far  as  its  posterior  border.     It  is  smaller  than  the 
posterior. 

The  posterior,  or  internal  crucial  ligament,  arises  from  the  depres- 
sion upon  the  head  of  the  tibia,  behind  the  spinous  process,  and 
passes  upwards  and  forwards  to  be  inserted  into  the  inner  condyle 
of  the  femur.  This  ligament  is  less  oblique  and  larger  than  the 
anterior. 

The  transverse  ligament  is  a  small  slip  of  fibres,  which  extends 
transversely  from  the  external  semilunar  fibro-cartilage,  near  its 
anterior  extremity,  to  the  anterior  convexity  of  the  internal  car- 
tilage. 

Fig.  66.  A  posterior  view  of  the  lig-aments  of  the  knee-joint.  1.  The  fasciculus  of 
the  ligamentum  posticum  Winslowi,  which  is  derived  from,  2.  The  tendon  of  the  semi- 
memtiranosus  muscle  ;  the  latter  is  cut  short.  3.  The  process  of  the  tendon  wliich 
spreads  out  in  the  fascia  of  the  popliteus  muscle.  4.  The  process  which  is  sent  inwards 
beneath  the  internal  lateral  ligament.  5.  The  posterior  part  of  the  internal  lateral 
ligament.  6.  The  long  external  lateral  ligament.  7.  The  short  externa!  lateral  liga- 
ment. 8.  The  tendon  of  the  popliteus  muscle  cut  short.  9.  The  posterior  superior 
tibio-fibular  ligrament. 


154 


KNEE  JOINT. 


The  coronary  liga?nents  are  the  short  fibres  by  which  the  convex 
borders  of  the  semilunar  cartilages  are  connected  to  the  head  of  the 
tibia,  and  to  the  ligaments  surrounding  the  joint. 


Fig.  67. 


Fig.  68. 


The  semilunar fihro-cartil ages,  arc  two  falciform  plates  of  fibro- 
cartilage,  situated  around  the  margin  of  the  head  of  the  tibia,  and 
serving  to  deepen  the  surface  of  articulation  for  the  condyles  of  the 
femur.  They  are  thick  along  their  convex  border,  and  thin  and 
sharp  along  the  concave  edge. 

The  internal  semilunar  jibro-cartilage  forms  an  oval  cup  for  the 

Fig.  67.  The  right  knee  joint  laid  open  from  the  front,  in  order  to  show  the  inter- 
nal ligaments.  1.  The  cartilaginous  surface  of  the  lower  extremity  of  the  femur  with 
its  two  condyles  ;  the  figure  5  rests  upon  the  external ;  the  figure  3  upon  the  internal 
condyle.  2.  The  anterior  crucial  ligament.  3.  The  posterior  crucial  ligament.  4. 
The  transverse  ligament.  5.  The  attachment  of  the  ligamentum  mucosum,  the  rest 
has  been  removed.  6.  The  internal  semilunar  fibro-cartilage.  7.  The  external  fibro- 
cartilage.  8.  A  part  of  the  ligamentum  patellae  turned  down.  9.  The  bursa,  situated 
between  the  ligamentum  patellae  and  the  head  of  the  tibia  ;  it  has  been  laid  open.  10. 
The  anterior  superior  tibio-fibular  ligament.  11.  The  upper  part  of  the  interosseous 
membrane,  the  opening  above  this  membrane  is  for  the  passage  of  the  anterior  tibial 
artery. 

Fig.  68.  A  longitudinal  section  of  the  left  knee  joint,  showing  the  reflections  of  its 
synovial  meml)rane.  1.  The  cancellous  structure  of  the  lower  part  of  the  femur.  2. 
The  tendon  of  the  extensor  muscles  of  the  leg.  3.  The  patella.  4.  The  ligamentum 
patellse.  5.  The  cancellous  structure  of  (he  head  of  the  tibia.  6.  A  bursa  situated 
between  the  ligamentum  patellae  and  the  head  of  the  tibia.  7.  The  mass  of  fat  pro- 
jecting into  the  cavity  of  the  joint  below  the  patella.  *  *  The  synovial  membrane. 
8.  The  pouch  of  synovial  membrane,  which  ascends  between  the  tendon  of  the  extensor 
muscles  of  the  leg,  and  the  front  of  the  lower  extremity  of  the  femur.  9.  One  of  the  alar 
ligaments;  the  other  has  been  removed  with  the  opposite  section.  10.  The  ligamentum 
.dnucosum  left  entire  ;  the  section  being  made  to  its  inner  side.  11.  The  anterior  or 
external  crucial  lijrament.  12.  The  posterior  ligament.  The  scheme  of  the  synovial 
membrane  which  is  here  presented  to  the  student,  is  divested  of  all  unnecessary  com- 
pliciitions.  It  may  be  traced  from  the  saceulus  (;it  8),  along  the  inner  surTace  of  the 
patella;  then  over  the  adipose  rnas.s  (7)  from  which  it  throws  off  the  mucous  ligament 
(10);  then  over  the  head  of  the  tibia,  forming  a  sheath  to  the  crucial  ligaments  ;  then 
upwards  along  the  posterior  ligament  and  condyles  of  the  femur,  to  the  saceulus  whence 
its  examination  commenced. 


KNEE  JOINT.  165 

reception  of  the  internal  condyle ;  it  is  connected  by  its  convex 
border  to  the  head  of  the  tibia,  and  to  the  internal  and  posterior 
ligaments,  by  nneans  of  its  coronary  ligament ;  and  by  its  two 
extremities  is  firmly  implanted  into  the  depression  in  front  and 
behind  the  spinous  process.  The  external  semilunar  jibro-cartilage 
bounds  a  circular  fossa  for  the  external  condyle ;  it  is  connected  by 
its  convex  border  with  the  head  of  the  tibia,  and  to  the  external  and 
posterior  ligaments,  by  means  of  its  coronary  ligament ;  by  its  two 
extremities  it  is  inserted  into  the  depression  between  the  two  pro- 
jections which  constitute  the  spinous  process  of  the  tibia.  The  tw^o 
extremities  of  the  external  cartilage  being  inserted  into  the  same 
fossa,  form  almost  a  complete  circle,  and  the  cartilage  being  some- 
what broader  than  the  internal,  nearly  covers  the  articular  surface  of 
the  tibia.  The  external  semilunar  fibro-cartilage,  besides  giving  off  a 
fasciculus  from  its  anterior  border  to  constitute  the  transverse  liga- 
ment, is  continuous  by  some  of  its  fibres  with  the  extremity  of  the 
anterior  crucial  ligament ;  posteriorly  it  divides  into  three  slips,  one, 
a  strong  cord,  ascends  obliquely  forwards  and  is  inserted  into  the 
anterior  part  of  the  inner  condyle  in  front  of  the  posterior  crucial 
ligament ;  another  is  the  fasciculus  of  insertion  into  the  fossa  of  the 
spinous  process  ;  and  the  third,  of  small  size,  is  continuous  with  the 
posterior  part  of  the  anterior  crucial  ligament. 

The  ligamentum  mucosum  is  a  slender  conical  process  of  syno- 
vial membrane,  enclosing  a  few  ligamentous  fibres  which  proceed 
from  the  transverse  ligament.  It  is  connected  by  its  apex  with  the 
anterior  part  of  the  condyloid  notch,  and  by  its  base  is  lost  in  the 
mass  of  fat  which  projects  into  the  joint  beneath  the  patella. 

The  alar  ligaments  are  two  fringed  folds  of  synovial  membrane, 
extending  from  the  ligamentum  mucosum,  along  the  edges  of  the 
mass  of  fat  to  the  sides  of  the  patella. 

The  synovial  membrane  of  the  knee  joint  is  by  far  the  most  exten- 
sive in  the  skeleton.  It  invests  the  cartilaginous  surface  of  the 
condyles  of  the  femur,  of  the  head  of  the  tibia,  and  of  the  inner 
surface  of  the  patella ;  it  covers  both  surfaces  of  the  semilunar 
fibro-cartilages,  and  is  reflected  upon  the  crucial  ligaments,  and 
upon  the  inner  surface  of  the  ligaments  which  form  the  circum- 
ference of  the  joint.  On  each  side  of  the  patella,  it  lines  the  tendi- 
nous aponeuroses  of  the  vastus  internus  and  vastus  externus  muscles, 
and  forms  a  pouch  of  considerable  size  between  the  extensor  tendon 
and  the  front  of  the  femur.  It  also  forms  the  folds  in  the  interior  of 
the  joint,  called  "  ligamentum  mucosum,"  and  "  ligamenta  alaria." 
The  superior  pouch  of  the  synovial  membrane  is  supported  and 
raised  during  the  movements  of  the  limb  by  a  small  muscle,  the 
suhcrureus,  which  is  inserted  into  it.  •  ' 

Beneath  the  ligamentum  patellae  and  the  synovial  membrane  is 
a  considerable  mass  of  fat,  which  presses  the  membrane  towards 
the  interior  of  the  joint,  and  occupies  the  fossa  between  the  two 
condyles. 

Besides  the  proper  ligaments  of  the  articulation,  the  joint  is  pro- 


156  TIBIO-FIBULAR  ARTICULATION. 

tected  on  its  anterior  part  by  the  fascia  lata,  which  is  thicker  upon 
the  outer  than  upon  the  inner  side,  by  a  tendinous  expansion  from 
the  vastus  internus,  and  by  some  scattered  ligamentous  fibres  which 
are  inserted  into  the  sides  of  the  patella. 

Actions. — The  knee  joint  is  one  of  the  strongest  of  the  articula- 
tions of  the  body,  while  at  the  same  time  it  admits  of  the  most  per- 
fect degree  of  movement  in  the  directions  of  Jlexion  and  extension. 
During  flexion  the  articular  surface  of  the  tibia  gHdes  forward  on 
the  condyles  of  the  femur,  the  lateral  ligaments,  the  posterior,  and 
crucial  ligaments  are  relaxed,  while  the  ligamentum  patellae  being 
put  upon  the  stretch,  serves  to  press  the  adipose  mass  into  the  vacuity 
formed  in  the  front  of  the  joint.  In  extension  all  the  ligaments  are 
put  upon  the  stretch  with  the  exception  of  the  ligamentum  patellae. 
When  the  knee  is  semi-flexed,  a  partial  degree  of  rotation  is 
permitted. 

3.  Articulation  between  the  Tibia  and  Fibula. — The  tibia  and 
fibula  are  held  firmly  connected  by  means  of  seven  ligaments,  viz. 

Anterior,  )    , 

■D    *    •       [  above. 

rosterior,  ) 

Interosseous  membrane. 
Interosseous  inferior. 

Anterior,   )  ,    , 
■n    ,    •       [  below. 
Jrosterior,  ) 

Transverse. 

The  anterior  superior  ligament  is  a  strong  fasciculus  of  parallel 
fibres,  passing  obliquely  downwards  and  outwards  from  the  inner 
tuberosity  of  the  tibia,  to  the  anterior  surface  of  the  head  of  the 
fibula. 

The  posterior  superior  ligament  is  disposed  in  a  similar  manner 
upon  the  posterior  surface  of  the  articulation. 

There  is  a  distinct  synovial  membrane  in  this  articulation. 

The  interosseous  membrane  or  superior  interosseous  ligament  is  a 
broad  layer  of  aponeurotic  fibres,  passing  obliquely  downwards  and 
outwards,  from  the  sharp  ridge  on  the  tibia,  to  the  inner  edge  of  the 
fibula,  and  crossed  at  an  acute  angle  by  a  few  fibres  passing  in  the 
opposite  direction.  The  ligament  is  deficient  above,  leaving  a  con- 
siderable interval  between  the  bones,  through  which  the  anterior 
tibial  artery  takes  its  course  forwards  to  the  anterior  aspect  of  the 
leg,  and  near  its  lower  third  there  is  an  opening  for  the  anterior 
peroneal  artery  and  vein. 

The  interosseous  membrane  is  in  relation,  in  front,  with  the 
tibialis  anticus,  extensor  longus  digitorum,  and  extensor  proprius 
pollicis  muscle,  with  the  anterior  tibial  vessels  and  nerve,  and  with 
the  anterior  peroneal  artery ;  and  behind  with  the  tibiaUs  posticus, 
and  flexor  longus  digitorum  muscle,  and  with  the  posterior  peroneal 
artery. 

The  inferior  interosseous  ligament  consists  of  short  and  strong 
fibres,  which  hold  the  bones  firmly  together,  inferiorly  where  they 


ANKLE  JOINT. 


157 


are  nearly  in  contact.  This  articulation  is  so  firm  that  the  fibula 
is  likely  to  be  broken  in  the  attempt  to  rupture  the  ligament. 

The  anterior  inferior  ligament  is  a  broad  band,  consisting  of  two 
fasciculi  of  parallel  fibres  that  pass  obliquely  across  the  anterior  as- 
pect of  the  articulation  of  the  two  bones  at  their  inferior  extremity, 
from  the  tibia  to  the  fibula. 

The  posterior  inferior  ligament  (fig.  71.  2)  is  a  similar  band  upon 
the  posterior  surface  of  the  articulation.  Both  ligaments  project 
somewhat  below  the  margin  of  the  bones,  and  serve  to  deepen  the 
cavity  of  articulation  for  the  astragalus. 


Fig.  69. 


Fig.  70. 


The  transverse  ligament  (fig.  71.  3)  is  a  narrow  band  of  ligamen- 
tous fibres,  continuous  with  the  preceding,  and  passing  transversely 
across  the  back  of  the  ankle  joint  between  the  two  malleoli. 

The  synovial  membrane  of  the  inferior  tibio-fibular  articulation,  is 
a  duplicature  reflected  upwards  for  a  short  distance  between  the 
two  bones. 

Actions. — An  obscure  movement  exists  between  the  tibia  and 
fibula,  which  is  principally  calculated  to  enable  the  latter  to  resist 
injury  by  yielding  for  a  trifling  extent  to  the  pressure  exerted. 

4.  JinUe  joint. — The  ankle  is  a  ginglymoid  articulation,  the  sur- 
faces entering  into  the  formation  of  the  joint  are  the  under  surface 
of  the  tibia  with  its  malleolus  and  the  malleolus  of  the  fibula,  above; 
and  the  surface  of  the  astragalus  with  its  two  lateral  facets,  below. 
The  ligaments  are  three  in  number : 

Anterior, 
Internal  lateral, 
External  lateral. 


Fig.  69.  An  internal  view  of  the  ankle  joint.  1.  The  internal  malleolus  of  the  tibia. 
2,  2.  Part  of  the  astragalus  ;  the  rest  is  concealed  by  tlie  ligaments.  3.  The  os  calcis. 
4.  The  scaphoid  bone.  5.  The  internal  cuneiform  bone.  6.  The  internal  lateral  or 
deltoid  ligament.  7.  The  anterior  ligament.  8.  The  ttndo  Achillis ;  a  small  bursa  is 
seen  interposed  between  this  tendon  and  the  tuberosity  of  the  os  calcis. 

Fig.  70.  An  external  view  of  the  ankle  joint.  1.  The  tibia.  2.  The  exiernal  mal- 
leolus of  the  fibula.  3,3.  The  astragalus.  4.  The  os  calcis.  5.  The  cuboid  bone.  6. 
The  anterior  fasciculus  of  the  external  lateral  ligament  attached  to  the  astragalus.  7. 
Its  middle  fasciculus,  attached  to  the  os  calcis.  8.  Its  posterior  fasciculus,  attached  to 
tlie  astragalus.     9.  The  anterior  ligament  of  tlie  ankle. 

14 


158  TARSAL  ARTICULATIONS. 

The  anterior  ligament  is  a  thin  membranous  layer,  passing  from 
the  margin  of  the  tibia  to  the  astragalus  in  front  of  the  articular  sur- 
face. It  is  in  relation,  in  front,  with  the  extensor  tendons  of  the 
great  and  lesser  toes,  with  the  tendon  of  the  tibialis  anticus  and 
peroneus  tertius,  and  with  the  anterior  tibial  vessels  and  nerve. 
Posteriorly  it  lies  in  contact  with  the  extra-synovial  adipose  tissue 
and  with  the  synovial  membrane. 

The  internal  lateral  ligament  or  deltoid,  is  a  triangular  layer  of 
fibres  attached  superiorly  by  its  apex  to  the  internal  malleolus,  and 
inferiorly  by  an  expanded  base  to  the  astragalus,  os  calcis,  and  sca- 
phoid bone.  Beneath  the  superficial  layer  of  this  ligament  is  a  much 
stronger  and  thicker  fasciculus  of  fibres,  which  connects  the  apex  of 
the  internal  malleolus  with  the  side  of  the  astragalus. 

This  internal  lateral  ligament  is  covered  in  and  partly  concealed 
by  the  tendon  of  the  tibialis  posticus,  and  its  posterior  part  is  in 
relation  with  the  tendon  of  the  flexor  longus  digitorum,  and  of  the 
flexor  longus  pollicis. 

The  external  lateral  ligament  consists  of  three  strong  fasciculi, 
which  proceed  from  the  inner  side  of  the  external  malleolus,  and 
diverge  in  three  different  directions.  The  anterior  fasciculus  passes 
forwards,  and  is  attached  to  the  astragalus ;  the  posterior  back- 
wards, and  is  connected  with  the  astragalus  posteriorly ;  and  the 
middle,  longer  than  the  other  two,  descends  to  be  inserted  into  the 
outer  side  of  the  os  calcis. 

"  It  is  the  strong  union  of  this  bone,"  says  Sir  Astley  Cooper,  "with 
the  tarsal  bones  by  means  of  the  external  lateral  ligaments,  which 
leads  to  its  being  more  frequently  fractured  than  dislocated." 

The  transverse  ligament  of  the  tibia  and  fibula  occupies  the  place 
of  a  posterior  ligament.  It  is  in  relation,  behind,  with  the  posterior 
tibial  vessels  and  nerve,  and  with  the  tendon  of  the  tibialis  posticus 
muscle ;  and  in  front,  with  the  extra-synovial  adipose  tissue,  and 
synovial  membrane. 

The  Synovial  membrane  invests  the  cartilaginous  surfaces  of  the 
tibia  and  fibula,  sending  a  duplicature  upwards  between  their  lower 
ends ;  and  the  upper  surface  and  two  sides  of  the  astragalus.  It  is 
then  reflected  upon  the  anterior  and  lateral  ligaments,  and  upon  the 
transverse  ligament  posteriorly. 

Actions. — The  movements  of  the  ankle  joint  are  flexion  and  ex- 
tension only,  without  lateral  motion. 

5.  Articulations  of  the  Tarsal  Bones. — The  ligaments  which  con- 
nect the  seven  bones  of  the  tarsus  to  each  other  are  of  three  kinds, — 

Dorsal, 
Plantar, 
Interosseous. 

The  dorsal  ligaments  are  small  fasciculi  of  parallel  fibres,  which 
pass  from  each  bone  to  all  the  neighbouring  bones  with  which  it 
articulates.  The  only  dorsal  ligaments  deserving  of  particular 
mention  are,  the  external  and  posterior  calcaneo-astragaloid,  which, 


TARSAL  ARTICULATIONS. 


159 


Fig.  71. 


with  the  interosseous  h'gament,  complete  the  articulations  of 
the  astragalus  with  the  os  calcis ;  the  superior  and  internal 
calcaneo-cuboid  liganaents;  and  the  superior  astragalo-scaphoid 
Hgament.  The  internal  calcaneo-cuboid  and  the  superior  calcaneo- 
scaphoid  ligament,  which  are  closely  united  posteriorly  in  the  deep 
groove  which  intervenes  between  the  astragalus  and  os  calcis, 
separate  anteriorly  to  reach  their  respective  bones,  and  form  the 
principal  bond  of  connexion  between  the  first  and  second  range  of 
bones  of  the  foot.  It  is  the  division  of  this  portion  of  these  liga- 
ments that  demands  the  especial  attention  of  the  surgeon  in  per- 
forming Chopart's  operation. 

The  plantar  ligaments  have  the  same  disposition  on  the  plantar 
surface  of  the  foot ;  three  of  them,  however,  are  of  large  size  and 
have  especial  names,  viz.  the 

Calcaneo-scaphoid, 
Long  calcaneo-cuboid, 
Short  calcaneo-cuboid. 

The  inferior  calcaneo-scaphoid  ligament  is  a  broad  and  fibro- 
cartilaginous band  of  ligament,  which  passes  for- 
wards from  the  anterior  and  inner  border  of  the  os 
calcis  to  the  edge  of  the  scaphoid  bone.  In  addition 
to  connecting  the  os  calcis  and  scaphoid,  it  sup- 
ports the  astragalus,  and  forms  part  of  the  cavity  in 
which  its  rounded  head  is  received.  It  is  lined 
upon  its  upper  surface  by  the  synovial  membrane  of 
the  astragalo-scaphoid  articulation. 

The  firm  connexion  of  the  os  calcis  with  the 
scaphoid  bone,  and  the  feebleness  of  the  astragalo- 
scaphoid  articulation  are  conditions  favourable  to 
the  occasional  dislocation  of  the  head  of  the  astra- 
galus. 

The  long  calcaneo-cuboid,  or  ligamentum  longum 
plantcE,  is  a  long  band  of  ligamentous  fibres,  which 
proceeds  from  the  under  surt'ace  of  the  os  calcis  to  the  rough  sur- 
face on  the  under  part  of  the  cuboid  bone,  its  fibres  being  continued 
onwards  to  the  bases  of  the  third  and  fourth  metatarsal  bones. 

This  ligament  forms  the  inferior  boundary  of  a  canal  in  the 
cuboid  bone,  through  which  the  tendon  of  the  peroneus  longus 
passes  to  its  insertion  into  the*base  of  the  metatarsal  bone  of  the 
great  toe. 

The  short  calcaneo-cuboid,  or  ligamentum  breve  plantce,  is  situated 
nearer  to  the  bones  than  the  long  plantar  ligament,  from  which  it 
is  separated  by  adipose  tissue;  it  is  broad  and  extensive,  and  ties 
the  under  surface  of  the  os  calcis  and  cuboid  bone  firmly  together. 

The  interosseous  ligaments  are  five  in   number  ;   they  are  short 

Fig.  71.  A  posterior  view  of  the  anlde  joint.  1.  The  lower  part  of  the  interosseous 
membrane.  2.  The  posterior  inferior  ligament  connecting  the  tibia  and  fibula.  3.  The 
transverse  ligament,  4.  The  internal  lateral  ligament.  5.  The  posterior  fisciculus 
of  the  external  lateral  ligament.  6.  The  middle  fasciculus  of  the  external  ligament, 
7.  The  synovial  membrane  of  the  ankle  joint.     8.  The  os  calcis. 


160 


TAKSO-METATAESAL  ARTICULATIONS. 


Fig.  72. 


and  strong  ligamentous  fibres  situated  between  adjoining  bones, 
and  firmly  attached  to  their  rough  surfaces.  One  of  these,  the 
calcaneo-astragahid,  is  lodged  in  the  groove  between  the  upper 
surface  of  the  os  calcis,  and  the  lower  of  the  astragalus.  It  is 
large  and  very  strong,  consists  of  vertical  and  oblique  fibres,  and 
serves  to  unite  the  os  calcis  and  astragalus  solidly  together.  The 
second  interosseous  ligament,  also  very  strong,  is  situated  between 
the  sides  of  the  scaphoid  and  cuboid  bone;  while  the  three  remain- 
ing ligaments  connect  strongly  together  the  three  cuneiform  bones 
and  the  cuboid. 

The  synovial  membranes  of  the  tarsus  are  four  in  number;  one, 
for  the  posterior  calcaneo-astragaloid  articulation ;  a  second,  for  the 
anterior  calcaneo-astragaloid  and  astragalo-scaphoid  articulation. 
Occasionally  an  additional  small  synovial  membrane  is  found  in 
the  anterior  calcaneo-astragaloid  joint;  a  third,  for  the  calcaneo- 
cuboid articulation;  and  a  fourth,  the  large  tarsal  synovial  mem- 
brane, for  the  articulations  between  the  scaphoid  and  three  cunei- 
form bones,  the  cuneiform  bones  with  each 
other,  the  external  cuneiform  bone  with  the  cu- 
boid, and  the  two  external  cuneiform  bones  with 
the  bases  of  the  second  and  third  metatarsal 
bones.  The  prolongation  which  reaches  the  meta- 
tarsal bones  passes  forwards  between  the  inter- 
nal and  middle  cuneiform  bones.  A  small  syno- 
vial membrane  is  sometimes  met  with  between 
the  contiguous  surfaces  of  the  scaphoid  and  cu- 
boid bone. 

Actions. — The  movements  permitted  by  the  ar- 
ticulation between  the  astragalus  and  os  calcis,  are 
a  slight  degree  of  gliding,  in  the  directions /brioarcZs 
and  hackioards  and  laterally  from  side  to  side. 
The  movements  of  the  second  range  of  tarsal 
bones  are  very  trifling,  being  greater  between  the 
scaphoid  and  three  cuneiform  bones  than  in  the 
other  articulations.  The  movements  occurring 
between  the  first  and  second  range  are  the  most 
considerable ;  they  are  adduction  and  abduction, 
and,  in  a  nninor  degree,  fiexion,  which  increases 
the  arch  of  the  foot,  and  extension,  which  flattens 
the  arch. 
G.  Tarso-metatarsal  Articulations. — The  ligaments  of  this  articu- 
lation are, 


Fig.  72.  The  ligaments  of  the  sole  of  the  foot.  1.  The  os  calcis.  2.  The  astragalus. 
3.  The  tuberosity  of  the  sciiphoid  bone.  4.  The  long  calcaneo-cuboid  ligament.  5. 
Part  of  the  short  calcanco-cuboid  ligament.  6.  The  ealeanco-scaphoid  ligament.  7. 
The  plantar  tarsal  ligaments.  8,  8.  The  tendon  of  the  peroncus  longns  muscle.  9,  9. 
Plantar  tarso-rnctatarsal  ligaments.  10.  Plantar  ligament  of  the  mctatarso-plialangeal 
articulation  of  tlie  great  toe;  the  same  ligament  is  seen  upon  the  otlier  toes.  1.1. 
Lfiteriil  ligaments  of  the  metalarso-phalangeal  articulation.  12.  Transverse  ligament. 
13.  The  lateral  ligaments  of  the  phalanges  of  the  great  toe ;  the  same  ligaments  are 
seen  upon  the  oilier  toes. 


METATARSO-PHALANGEAL  ARTICULATIONS.  161 

Dorsal, 
Plantar, 
Interosseous. 

The  dorsal  ligaments  connect  the  metatarsal  to  the  tarsal  bones, 
and  the  metatarsal  bones  with  each  other. 

The  plantar  ligaments  have  the  same  disposition  on  the  plantar 
surface. 

The  interosseous  ligaments  are  situated  between  the  bases  of  the 
metatarsal  bones  of  the  four  lesser  toes,  and  also  between  the  base 
of  the  second  metatarsal  bone,  and  the  internal  and  external  cunei- 
form bone. 

The  metatarsal  bone  of  the  second  toe  is  implanted  by  its  base 
between  the  internal  and  external  cuneiform  bones,  and  is  the  most 
strongly  articulated  of  all  the  metatarsal  bones.  This  disposition 
must  be  recollected  in  amputation  at  the  tarso-metatarsal  articula- 
tion. 

The  synovial  membranes  of  this  articulation  are  three  in  number: 
one  for  the  metatarsal  bone  of  the  great  toe ;  one  for  the  second  and 
third  metatarsal  bones,  which  is  continuous  with  the  great  tarsal 
synovial  membrane;  and  one  for  the  fourth  and  fifth  metatarsal 
bones. 

Actions. — The  movements  of  the  metatarsal  bones  upon  the  tarsal 
and  upon  each  other  are  very  slight ;  they  are  such  only  as  contri- 
bute to  the  strength  of  the  foot  by  permitting  a  certain  degree  of 
yielding  to  opposing  forces. 

7.  Metatarso-phalangeal  Articulation. — The  ligaments  of  this  ar- 
ticulation, like  those  of  the  articulation  between  the  first  phalanges 
and  metacarpal  bones  of  the  hand,  are, 

Anterior  or  plantar, 
Two  lateral, 
Transverse. 

The  anterim'  or  plantar  ligaments  are  thick  and  fibro-cartilagi- 
nous,  and  form  part  of  the  articulating  surface  of  the  joint. 

The  lateral  ligaments  are  short  and  very  strong,  and  situated  on 
each  side  of  the  joints. 

The  transverse  ligaments  are  strong  bands,  which  pass  trans- 
versely between  the  anterior  ligaments. 

The  expansion  of  the  extensor  tendon  supplies  the  place  of  a  dor- 
sal ligament. 

Actions. — The  movements  of  the  first  phalanges  upon  the  rounded 
heads  of  the  metatarsal  bones  are  fexion,  extension,  adduction  and 
abduction. 

8.  Articulation  of  the  Phalanges. — The  ligaments  of  the  phalanges 
are  the  same  as  those  of  the  fingers,  and  have  the  same  disposition ; 
their  actions  are  also  similar.     They  are, 

Anterior  or  plantar, 
Two  lateral. 

14* 


CHAPTER    III. 

ON  THE  MUSCLES. 

Muscles  are  the  moving  organs  of  the  animal  frame:  they  con- 
stitute by  their  size  and  number  the  great  bulk  of  the  body,  upon 
which  they  bestow  form  and  symmetry.  In  the  limbs  they  are  situated 
around  the  bones,  which  they  invest  and  defend,  while  they  form  to 
some  of  the  joints  a  principal  protection.  In  the  trunk  they  are 
spread  out  to  enclose  cavities,  and  constitute  a  defensive  wall  capa- 
ble of  yielding  to  internal  pressure,  and  again  returning  to  its  origi- 
nal form. 

Their  colour  presents  the  deep  red  which  is  characteristic  of 
flesh,  and  their  form  is  variously  modified,  to  execute  the  varied 
range  of  movements  which  they  are  required  to  effect. 

Muscle  is  composed  of  a  number  of  parallel  fibres  placed  side  by 
side,  and  supported  and  held  together  by  a  delicate  web  of  cellular 
tissue  ;  so,  that  if  it  were  possible  to  remove  the  muscular  substance, 
we  should  have  remaining  a  beautiful  cellular  framework,  possess- 
ing the  exact  form  and  size  of  the  muscle  without  its  colour  and 
solidity.  Towards  the  extremity  of  the  organ  the  muscular  fibre 
ceases,  and  the  cellular  structure  becomes  aggregated  and  modified, 
so  as  to  constitute  those  glistening  fibres  and  cords  by  which  the 
muscle  is  tied  to  the  surface  of  bone,  and  which  are  called  tendons. 
Almost  every  muscle  in  the  body  is  connected  with  bone,  either  by 
tendinous  fibres,  or  by  an  aggregation  of  those  fibres  constituting  a 
tendon ;  and  the  union  is  so  firm,  that,  under  extreme  violence,  the 
bone  itself  rather  breaks  than  permits  of  the  separation  of  the  tendon 
from  its  attachment.  In  the  broad  muscles  the  tendon  is  spread  so 
as  to  form  an  expansion,  called  aponeurosis  (airo,  long ;  vsu^ov,*  ner- 
vus — a  nerve  widely  spread  out). 

Muscles  present  various  modifications  in  the  arrangement  of  their 
fibres  in  relation  to  their  tendinous  structure.  Sometimes  they  are 
completely  longitudinal,  and  terminate  at  each  extremity  in  tendon, 
the  entire  muscle  being  fusiform  in  its  shape ;  in  other  situations 
they  are  disposed  like  the  rays  of  a  fan,  converging  to  a  tendinous 
point,  as  the  temporal,  pectoral,  glutei,  &c.,  and  constitute  a  radiate 
muscle.  Again,  they  are  penniform,  converging  like  the  plumes  of 
a  pen  to  one  side  of  a  tendon  which  runs  the  whole  length  of  the 

*  The  ancients  named  all  the  white  fibres  of  the  body  vsuga;  the  term  has  since  been 
limited  to  the  nerves. 


STRUCTURE  OF  MUSCLES. 


163 


muscle,  as  in  the  peronei ;  or  bipenniform,  converging  to  both  sides 
of  the  tendon.  In  other  muscles  the  fibres  pass  obliquely  from  the 
surface  of  a  tendinous  expansion  spread  out  on  one  side,  to  that  of 
another  extended  on  the  opposite  side,  as  in  the  semi-membranosus ; 
or  they  are  composed  of  penniform  or  bipenniform  fasciculi  as  in  the 
deltoid,  and  constitute  a  compound  muscle. 

The  nomenclature  of  the  muscles  is  defective  and  confused,  and 
is  generally  derived  from  some  prominent  character  which  each 
muscle  presents :  thus,  some  are  named  from  their  situation,  as  the 
tibialis,  peroneus ;  others  from  their  uses,  as  the  flexors,  extensors, 
adductors,  abductors,  levators,  tensors,  &c.  Some  again  from  their 
form,  as  the  trapezius,  triangularis,  deltoid,  &c. ;  and  others  from 
their  direction,  as  the  rectus,  obliquus,  transversalis,  &c.  Some 
muscles  have  received  names  expressive  of  their  attachments,  as  the 
sterno-mastoid,  sterno-hyoid,  &c. ;  and  others,  of  their  divisions,  as 
the  biceps,  triceps,  digastricus,  complexus,  &c. 

In  the  description  of  a  muscle  we  express  its  attachment  by  the 
words  "origin"  and  "insertion 
applied  to  the  more  fixed  or  cen- 


the  term  origin  being  generally 
Fig.  73. 


tral  attachment,  or  to  the  point  to- 
wards which  the  motion  is  di- 
rected while  insertion  is  assigned 
to  the  more  movable  point,  or 
to  that,  most  distant  from  the 
centre ;  but  there  are  many  ex- 
ceptions to  this  principle,  and  as 
many  muscles  pull  equally  by 
both  extremities,  the  use  of  such 
terms  must  be  regarded  as  purely 
arbitrary. 

In  structure,  muscle  is  com- 
posed of  bundles  of  fibres  of  va- 
riable size  called  fasciculi,  which  are  enclosed  in  a  cellular  mem- 
branous investmeiit  or  sheath,  and  the  latter  is  continuous  with  the 
cellular  framework  of  the  fibres.  Each  fasciculus  is  composed  of 
a  number  of  smaller  bundles,  and  these  of  single  fibres,  which,  from 
their  minute  size  and  independent  appearance,  have  been  distin- 
guished by  the  name  of  ultimate  fibres.    The  ultimate  fibre  is  found 

Fig.  73.  1.  A  muscular  fibre  of  animal  life  enclosed  in  its  myolemma ;  the  trans- 
verse and  longitudinal  strias  are  seen. 

2.  An  ultimate  fibril  of  muscular  fibre  of  animal  life. 

3.  A  muscular  fibre  of  animal  life,  similar  to  1  but  more  highly  magnified.  Its 
myolemma  is  so  thin  and  transparent  as  to  permit  the  ultimate  fibrils  to  be  seen  through. 
The  true  nature  of  the  longitudinal  stria;  is  seen  in  this  fibre  as  well  as  the  mode  of 
formation  of  the  transverse  striee. 

4.  A  muscular  fibre  of  organic  life  from  the  urinary  bladder,  magnified  600  times, 
Hjiear  measure.     Two  of  the  nuclei  are  seen. 

5.  A  muscular  fibre  of  organic  life,  from  the  stomach,  magnified  600  times.  The 
diameter  of  this  and  of  the  preceding  fibre,  midway  between  the  nuclei,  was  l-4750th 
of  an  inch. 


164 


STKUCTURE  OF  MUSCLES. 


by  microscopic  investigation,  to  be  itself  made  up  of  a  number  of 
ultimate  fibrils  enclosed  in  a  delicate  sheath  or  myolemma.*  Two 
kinds  of  ultimate  muscular  fibre  exist  in  the  animal  economy ;  viz., 
that  of  voluntary  or  animal  life,  and  that  of  involuntary  or  organic 
life. 

The  f.hre  of  animal  life  is  recognised  from  being  marked  by 
transverse  and  slightly  waving  striae.  The /iire  of  organic  life  has 
no  transverse  strijB,  and  is  much  smaller  than  the  fibre  of  animal 
life.  It  is  polygonal  in  form  or  nearly  cylindrical,  and  appears  to 
consist  of  a  number  of  minute  parallel  filaments  enclosed  in  a  myo- 
lemma. The  most  remarkable  character  of  the  organic  fibre  is  the 
existence  from  point  to  point  of  swellings  somewhat  larger  than  the 
diameter  of  the  fibre,  and  produced  by  the  nuclei  of  the  original 
nucleated  cells  from  which  the  fibre  was  developed. 


Fig.  74. 


WB       ft 


The  ultimate  fibrils  are  minute  beaded  filaments  in  the  fibre  of 
animal  life,  and  cylindrical  and  uniform  in  the  organic  fibre. 
-  According  to  the  researches  of  Mr.  Bowmanf  the  ultimate  fibres 
(primitive  fasciculi)  are  polygonal,  a  form  which  is  well  suited  to 
admit  of  their  being  collected  into  bundles.  In  size  they  are  very 
variable,  not  only  in  the  different  classes  and  genera  of  animals, 
but  also  in  the  same  animal  and  even  in  the  same  muscle.     He 


Tig.  74.  Developement  of  muscular  fibre.  1.  Primitive  cells  of  muscle  in  a  linear 
series.  2.  The  cells  united  and  the  nuclei  separated.  3  and  4.  The  transverse  striae 
are  becoming  apparent.  5.  Transverse  striae  formed  and  nuclei  disappearing.  6.  A 
fully  formed  muscular  fibre  treated  with  acetic  acid,  which  devolopes  the  nuclei  pre- 
viously concealed.     The  whole  magnified  300  diameters. 

*  In  the  summer  of  1836,  while  engaged  with  Dr.  Jones  Quain  in  the  examination 
of  the  animal  tissues,  with  a  simple  dissecting  microscope,  constructed  by  Powell,  I 
first  saw  that  the  ultimate  fibre  of  muscle  was  invested  by  a  proper  shealh,  for  which 
I  proposed  the  term  "  Myolemma  ;"  a  term  wiiich  was  adopted  by  Dr.  Quain  in  the 
fourth  edition  of  his  "  Elements  of  Anatomy."  We  at  that  time  believed  that  the 
transverse  folding  of  that  sheath  gave  rise  lo  the  appearance  of  transverse  striae,  an 
opinion  which  piibsc(]ucnt  examinations  proved  to  be  incorrect.  Mr.  Bowman  employs 
the  lerin  "  Sarcolcmma"  as  synonymous  with  Myolemma.  "' 

t  On  the  Minute  Structure  and  Movements  of  Voluntary  Muscle.  By  Wm.  Bow- 
man, Esq.     From  the  Philosophical  Transactions  for  1810. 


STRITCTURE  OF  MUSCLE3. 


165 


has  observed,  moreover,  that  they  are  somewhat  smaller  in  the 
female  than  in  the  male  ;  thus  the  average  diameter  of  the  ultimate 
fibre  in  the  female,  is  -ji^f;  in  the  male  ^j^;  the  average  of 
both  being  ■^^^.  In  the  different  classes  of  animals  examined 
by  Mr.  Bowman,  the  largest  ultimate  fibre  was  met  with  in 
fishes,  in  which  the  average  diameter 
is  2^5  ;  next  in  man;  and  then  in  other  ^'^S-  '''5. 

classes  in  the  following  order:  insects,  i 


4rl-g-;    reptiles,    ^U;    mammalia,    -^-^ ^ ; 


birds,  -^^y 

The  tdtimate  -fibrils,  (primitive  fibrillse) 
consist  of  segments  separated  from 
each  other  by  constrictions,  which 
give  to  the  entire  fibril  the  appearance 
of  a  string  of  beads.  The  constric- 
tions are  narrower  than  the  segments, 
and  their  component  substance  is  pro- 
bably less  dense  than  that  which  forms 
the  segments.  An  ultimate  fibre  con- 
sists of  a  bundle  of  fibrils,  which  are  so 
disposed  that  all  the  segments  and  all 
the  constrictions  correspond,  and  these 
give  rise  to  the  alternate  light  and  dark 
lines  of  the  transverse  strice.  The 
fibrils  are  connected  together  with  very 
different  degrees  of  closeness  in  different 
animals ;  in  man  they  are  but  slightly  adherent,  and  distinct  lon- 
gitudinal lines  of  junction  may  be  observed  between  them, — they 
also  separate  very  easily  when  macerated  for  some  time.  Besides 
the  more  usual  separation  of  the  ultimate  fibre  into  fibrils,  it  breaks, 
when  stretched,  into  transverse  sections,  corresponding  with  the 
dark  line  of  the  striae,  and  consequently  with  the  constrictions  of 
the  fibrillse.  When  this  division  occurs  with  the  greatest  facility, 
the  longitudinal  lines  are  indistinct  or  scarcely  perceptible.  "  In 
fact,"  says  Mr.  Bowman,  "the  primitive  fasciculus  seems  to  consist 
of  primitive  component  segments  or  particles,  arranged  so  as  to 
form,  in  one  sense,  fibrillee,  and  in  another  sense,  discs ;  and  which 
of  these  two  may  happen  to  present  themselves  to  the  observer,  will 
depend  on  the  amount  of  adhesion,  endways  or  sideways,  existing 
between  the  segments.  Generally,  in  a  recent  fasciculus,  there  are 
transverse  strise,  showing  divisions  into  discs,  and  longitudinal 
striae,  marking  its  composition  by  fibrillse." 

Mr.  Bowman  has  observed  that  in  the  substance  of  the  ultimate 


Fig.  75.  1.  Transverse  section  of  ultimate  fibres  of  the  biceps,  copied  from  the 
illustrations  to  Mr.  Bowman's  paper.  In  this  figure  the  polygonal  form  of  the  fibres 
is  seen,  and  their  composition  of  ultimate  fibrils. 

2.  An  ultimate  fibre,  in  which  the  transverse  splitting  into  discs,  in  the  direction  of 
the  constrictions  of  the  ultimate  fibrils  is  seen.     From  Mr.  Bowman's  paper. 


Iff6  MUSCLES  OF  THE  HEAD  AND  NECK. 

fibre  there  exist  minute  "  oval  or  circular 

Fig.  76.  discs,  frequently  concave  on  one  or  both 

•  surfaces,     and     containing,     somewhere 

__ ~-^£=^^__     near  the  centre,  one,  two  or  three  minute 

"^^^^^^^^^^^     dots    or    granules."     Occasionally    they 
<^j''^—^=-^^    —    -      are  seen  to  present  irregularities  of  form, 
^^^g^^^^^=r7    which  Mr.  Bowman  is  inclined  to  regard 
_2^^^^^^^^^^P    as    accidental.      They  are   situated    be- 
"^^^^^^sjr-^sr        tween,   and     are     connected     with,   the 
•^^^^^^^E^^^^     fibrils,   and     are     distributed    in     pretty 
^^^^""^^^^^^^^-^       equal  numbers  through  the  fibre.     These 
corpuscles  are  the  nuclei  of  the    nucle- 
ated cells  from  which  the  muscular  fibre  was  originally  developed. 
From  observing,  however,  that  their   "  absolute   number   is    far 
greater  in  the  adult  than  in  the  foetus,  while  their  number,  rela- 
tively to  the  bulk  of  the  fasciculi,  at  these  two  epochs,  remains 
nearly  the  same,"  Mr.  Bowman  regards  it  as  certain,  that  "  during 
developement,  and  subsequently,  a  further  and  successive  deposit  of 
corpuscles"  takes  place.     The  corpuscles  are  only  brought  into 
view  when  the  muscular  fibre  is  acted  upon  by  a  solution  of  "  one 
of  the  milder  acids,  as  the  citric." 

Muscles  are  divided  into  two  great  classes,  voluntary  and 
involuntary,  to  which  may  be  added  as  an  intermediate  and  con- 
necting link,  the  muscle  of  the  vascular  system,  the  heart. 

The  voluntary,  or  system  of  animal  life,  is  developed  from  the 
external  or  serous  layer  of  the  germinal  membrane,  and  compre- 
hends the  whole  of  the  muscles  of  the  limbs  and  of  the  trunk.  The 
involuntary  or  organic  system  is  developed  from  the  internal  or 
muGous  layer,  and  constitutes  the  thin  muscular  structure  of  the 
intestinal  canal,  bladder,  and  internal  organs  of  generation.  At  the 
commencement  of  the  alimentary  canal  in  the  oesophagus,  and 
near  its  termination  in  the  rectum,  the  muscular  coat  is  formed  by 
a  blending  of  the  fibres  of  both  classes.  The  heart  is  developed 
from  the  middle,  or  vascular  layer  of  the  germinal  membrane;  and 
although  involuntary  in  its  action,  is  composed  of  ultimate  fibres 
having  the  transverse  strioB  of  the  muscle  of  animal  life. 

The  muscles  may  be  arranged  in  conformity  with  the  general 
division  of  the  body  into, — 1.  Those  of  the  head  and  neck.  2. 
Those  of  the  trunk.  3.  Those  of  the  upper  extremity.  4.  Those 
of  the  lower  extremity. 

1.  MUSCLES  OF  THE  HEAD  AND  NECK. 

The  mdscles  of  the  head  and  neck  admit  of  a  subdivision  into 
those  of  the  head  and  face,  and  those  of  the  neck. 

Fig.  76.  Mass  of  ultimate  fibres  from  the  pcctoralis  major  of  the  liiiman  foetus,  at 
nine  montiis.  These  fibres  have  been  immersed  in  a  solution  of  tartaric  acid,  and  their 
"numerous  corpusculcs,  turned  in  various  directions,  some  presenting  nucleoli,"  are 
shown.     From  Mr.  Bowman's  paper. 


MUSCLES  OF  THE  HEAD  AND  KECK.  167 

Muscles  of  the  Head  and  Face. — These  muscles  may  be  divided 
into  groups  corresponding  with  the  natural  regions  of  the  head  and 
face;  the  groups  are  eight  in  number,  viz.: 

1.  Cranial  group.  5.  Superior  labial  group. 

2.  Orbital  group.  6.  Inferior  labial  group. 

3.  Ocular  group.  7.  Maxillary  group. 

4.  Nasal  group.  8.  Auricular  group. 

The  muscles  of  each  of  these  groups  may  be  thus  arranged — 

1.  Cranial  group.  Levator    labii    superioris  pro- 
Occipito-frontalis.  prius, 

o    n  1^:4  7  Levator  anguli  oris, 

2.  Orbital  grouv.  r,  ^-    °         • 

°      ^  Zygomaticus  major. 

Orbicularis  palpebrarum,  Zygomaticus  minor, 

Corrugator  supercilii.  Depressor  labii  superioris  alae- 

Tensor  tarsi.  que  nasi. 

3.  Ocular  group.  ,   6.  Inferior  labial  group. 

Levator  palpebrse,  '  (Orbicularis  oris,)* 

Rectus  superior,  Depressor  labii  inferioris, 

Rectus  inferior,  Depressor  anguli  oris. 

Rectus  internus.  Levator  labii  inferioris. 

Rectus  externus,  -,    ,^     .„ 

r\u^■  •  '•  Maxillary  group. 

Obliquus  superior,  ^  °      ^ 

Obliquus  inferior.  Masseter, 

A     -xr      1  Temporalis, 

4.  J\ as al  group.  r>       •     ^ 

°      ^  Buccmator, 

Pyramidalis  nasi,  Pterygoideus  externus, 

Compressor  nasi.  Pterygoideus  internus. 

5.  Superior  labial  group.  8.  Auricular  group. 

(Orbicularis  oris),  Attolens  aurem. 

Levator  labii  superioris  alaeque   Attrahens  aurem, 
nasi,  Retrahens  aurem. 

Dissection. — The  occipitofrontalis  is  to  be  dissected  by  making  a 
longitudinal  incision  along  the  vertex  of  the  head,  from  the  tubercle 
on  the  occipital  bone  to  the  root  of  the  nose ;  and  a  second  incision 
along  the  forehead  and  around  the  side  of  the  head,  to  join  the  two 
extremities  of  the  preceding.  Dissect  the  integument  and  superficial 
fascia  carefully  outwards,  beginning  at  the  anterior  angle  of  the 
flap,  where  the  muscular  fibres  are  thickest,  and  remove  it  alto- 
gether. This  dissection  requires  care;  for  the  muscle  is  very  thin, 
and  without  attention  would  be  raised  with  the  integument.  There 
is  no  deep  fascia  on  the  face  and  head,  nor  is  it  required ;  for  here 

*  The  orbicularis  oris,  from  encircling  the  mouth,  belongs  necessarily  to  both  the 
superior  and  inferior  labial  regions ;  it  is  therefore  enclosed  within  brackets  in  both. 


168 


OCCIPITO-FEONTALIS. 


Fig.  77. 


the  muscles  are  closely  applied  against  the  bones  upon  which  they 
depend  for  support,  whilst  in  the  extrennities  the  support  is  derived 
from  the  dense  layer  of  fascia  by  which  they  are  invested,  and 
which  forms  for  each  a  distinct  sheath. 

The  occipito-frontalis  is  a  broad  musculo-tendinous  layer,  which 
covers  the  whole  of  one  side  of  the  vertex  of  the  skull,  from  the 
occiput  to  the  eyebrow.  It  arises  by  tendinous  fibres  from  the 
outer  two-thirds  of  the  superior  curved  line  of  the  occipital  bone, 
and  from  the  mastoid  portion  of  the  temporal ;  it  is  inserted  into 
the  orbicularis  palpebrarum  muscle  and  the  internal  angular  process 
of  the  frontal  bone.     The  muscle  is  fleshy  in  front  over  the  frontal 

bone  and  behind  over  the  occipi- 
tal, the  portions  being  connected 
by  a  broad  aponeurosis.  The  two 
muscles  cover  the  whole  of  the 
vertex  of  the  skull,  hence  their 
designation  galea  capitis ;  they 
are  loosely  adherent  to  the  peri- 
cranium, but  very  closely  to  the 
integument,  particularly  over  the 
forehead. 

Relations. — This  muscle  is  in 
relation  by  its  external  surface 
from  before  backwards,  with  the 
frontal  and  supra-orbital  vessels, 
the  supra-orbital  and  fascial  nerve, 
the  temporal  vessels  and  nerve, 
the  occipital  vessels  and  nerves, 
and  with  the  integument,  to  which 
it  is  very  closely  adherent.  Its 
under  surface  is  attached  to  the 
pericranium  by  a  loose  cellular  tissue  which  admits  of  considerable 
movement. 

Action. — To  raise  the  eyebrows,  thereby  throwing  the  integument 
of  the  forehead  into  transverse  wrinkles.     Some  persons  have  the 


Fig.  77.  The  muscles  of  tlic  head  and  face.  1.  The  frontal  portion  of  the  occipito- 
frontalis.  2.  Its  occipital  portion.  3.  Its  aponeurosis,  4.  The  orbicularis  palpebrarum, 
which  conceals  the  corrugator  supercilii  and  tensor  tarsi.  5.  The  pyramidalis  nasi* 
6.  The  compressor  nasi.  7.  The  orbicularis  oris.  8.  The  levator  labii  superioris 
aleequc  nasi.  The  figure  is  placed  on  the  nasal  portion.  9.  The  levator  labii  supe- 
rioris proprius  ;  tlic  lower  part  of  the  levator  anguli  oris  is  seen  between  the  muscles 
10  and  11.  10.  1'he  zygornaticus  minor.  11.  The  zygomaticus  major.  12.  The 
depressor  labii  infcrioris.  13.  The  depressor  anguli  oris.  14.  The  levator  labii  infe- 
rioris.  15.  The  superficial  portion  of  tfie  masscter.  16.  Its  deep  portion.  17.  The 
attraheiis  aurem.  18.  The  buccinator.  19.  The  attolcns  aurcm.  20.  The  temporal 
fascia  which  covers  in  the  temporal  muscle.  21.  The  retrahens  aurem.  22.  The 
anterior  belly  of  the  digastricus  muscle ;  the  tendon  is  seen  passing  through  its 
aponeurotic  pulley.  23.  The  stylo-liyoid  muscle  pierced  by  the  posterior  belly  of  the 
digastricus.  24.  l^he  mylo-hyoidcus  muscle.  2.5.  The  upper  part  of  the  sterno-mas- 
toid.  26.  The  upper  part  of  the  trajiczius.  The  muscle  between  25  and  26  is  the 
splenius. 


ORBITAL  GROUP.  169 

power  of  moving  the  entire  scalp  upon  the  pericranium  by  means 
of  these  muscles. 

Dissection. — The  dissection  of  the  face  is  to  be  effected  by  con- 
tinuing the  longitudinal  incision  of  the  vertex  of  the  previous  dis- 
section onvi'ards  to  the  tip  of  the  nose,  and  thence  downwards  to 
the  margin  of  the  upper  lip ;  then  carry  an  incision  along  the 
margin  of  the  lip  to  the  angle  of  the  mouth,  and  transversely  across 
the  face  to  the  angle  of  the  lower  jaw.  Lastly,  divide  the  integu- 
ment in  front  of  the  external  ear  upwards  to  the  transverse  incision 
which  was  made  for  exposing  the  occipito-frontalis.  Dissect  the 
integument  and  superficial  fascia  carefully  from  the  whole  of  the 
region  included  by  these  incisions,  and  the  three  next  groups  of 
muscles  will  be  brought  into  view. 

2.  Orbital  group. — Orbicularis  palpebrarum, 
Corrugator  supercilii, 
Tensor  tarsi. 

The  orbicularis  palpebrarum  is  a  sphincter  muscle,  surrounding 
the  orbit  and  eyelids.  It  arises  from  the  internal  angular  process 
of  the  frontal  bone,  from  the  nasal  process  of  the  superior  maxillary, 
and  from  a  short  tendon  {tendo  oculi)  which  extends  between  the 
nasal  process  of  the  superior  maxillary  bone,  and  the  inner  ex- 
tremities of  the  tarsal  cartilages  of  the  eyelids.  The  fibres  encircle 
the  orbit  and  eyelids,  forming  a  broad  and  thin  muscular  plane, 
which  is  inserted  into  the  lower  border  of  the  tendo  oculi  and  into 
the  nasal  process  of  the  superior  maxillary  bone.  Upon  the  eyelids 
the  fibres  are  very  thin  and  pale,  and  possess  an  involuntary  action. 
The  tendo  oculi,  in  addition  to  its  insertion  into  the  nasal  process  of 
the  superior  maxillary  bone,  sends  a  process  inwards,  which  expands 
over  the  lachrymal  sac,  and  is  attached  to  the  ridge  of  the  lachry- 
mal bone :  this  is  the  reflected  aponeurosis  of  the  tendo  oculi. 

Relations. — By  its  superficial  surface  it  is  closely  adherent  to  the 
integument,  from  which  it  is  separated  over  the  eyelids  by  a  loose 
serous  cellular  tissue.  By  its  deep  surface  it  lies  in  contact  above 
with  the  upper  border  of  the  orbit,  with  the  corrugator  supercilii 
muscle,  and  with  the  frontal  and  supra-orbital  vessels  and  supra- 
orbital nerve  ;  below,  with  the  lachrymal  sac,  with  the  origins  of 
the  labii  superioris  alreque  nasi,  levator  labii  superioris  proprius, 
zygomaticus  major  and  minor  muscles,  and  malar  bone;  and  exter- 
nally with  the  temporal  fascia.  Upon  the  eyelid  it  is  in  relation 
with  the  broad  tarsal  ligament  and  tarsal  cartilages,  and  by  its  upper 
border  gives  attachment  to  the  occipito-frontalis  muscle. 

The  corrtigator  supercilii  is  a  small  narrow  and  pointed  muscle, 
situated  immediately  above  the  orbit  and  beneath  the  upper  segment 
of  the  orbicularis  palpebrarum  muscle.  It  arises  from  the  inner  ex- 
tremity of  the  superciUary  ridge,  and  is  inserted  into  the  under 
surface  of  the  orbicularis  palpebrarum. 

Relations. — By  its  superficial  surface,  with  the  pyramidalis  nasi, 

15 


170  OCULAR  GROUP. 

occipito-frontalis  arid  orbicularis  palpebrarum  muscle ;  and  by  its 
deep  surface  with  the  supra-orbital  vessels  and  nerve. 

The  tensor  tarsi  (Horner's*  muscle)  is  a  thin  plane  of  muscular 
fibres,  about  three  lines  in  breadth  and  six  in  length.  It  is  best  dis- 
sected by  separating  the  eyelids  of  the  eye,  and  turning  them  over 
the  nose  without  disturbing  the  tendo  oculi ;  then  dissect  away  the 
small  fold  of  mucous  membrane  called  plica  semilunaris,  and  some 
loose  cellular  tissue  under  which  the  muscle  is  concealed.  It  arises 
from  the  orbital  surface  of  the  lachrymal  bone,  and  passing  across 
the  lachrymal  sac  divides  into  two  slips,  which  are  inserted  into  the 
lachrymal  canals  as  far  as  the  puncta. 

Actions. — The  palpebral  portion  of  the  orbicularis  acts  involun- 
tarily in  closing  the  lids,  and  from  the  greater  curve  of  the  upper 
lid,  upon  that  principally.  The  entire  muscle  acts  as  a  sphincter, 
drawing  at  the  same  time,  by  means  of  its  osseous  attachment,  the 
integument  and  lids  inwards  towards  the  nose.  The  corrugatores 
supercihorum  draw  the  eyebrows  downwards  and  inwards,  and 
produce  the  vertical  wrinkles  of  the  forehead.  The  tensor  tarsi,  or 
Fig,  78.  lachrymal  muscle,  draws  the  extre- 

mities of  the  lachrymal  canals  in- 
wards, so  as  to  place  the  puncta  in 
the  best  position  for  receiving  the 
tears.  It  serves  also  to  keep  the 
lids  in  relation  with  the  surface  of 
the  eye,  and  compresses  the  lachry- 
mal sac.  Dr.  Horner  is  acquainted 
with  two  persons  who  have  the  vo- 
luntary power  of  drawing  the  lids 
inwards  by  these  muscles  so  as  to  bury  the  puncta  in  the  angle  of 
the  eye. 

3.  Ocular  group. — Levator  palpebrae, 
Rectus  superior, 
Rectus  inferior, 
Rectus  internus, 
,  Rectus  externus. 

Obliquus  superior, 
Obliquus  inferior. 

Dissection. — To  open  the  orbit  (the  calvarium  and  brain  having 
been  removed)  the  frontal  bone  must  be  sawn  through  at  the  inner 
extremity  of  the  orbital  ridge ;  and,  externally,  at  its  outer  extremity. 
The  roof  of  the  orbit  may  then  be  comminuted  by  a  few  light  blows 
with  the  hammer;  a  process  easily  accomplished,  on  account  of  the 
thinness  of  the  orbital  plate  of  the  frontal  bone  and  lesser  wing  of 

Fig,  78.  A  view  of  the  tensor  tarsi  muscle.  1,1,  Bony  margins  of  the  orbit.  2. 
Opening  between  the  eyelids.  3.  Internal  face  of  the  orbit.  4.  Origin  of  the  tensor 
tarsi.     5,  5.  Insertion  into  the  nciglibourhood  of  the  puneta  lachrymalia. 

*  W.  E.  Horner,  M.D.,  Professor  of  Anatomy  in  tiie  University  of  Pennsylvania. 
The  notice  of  this  discovery  is  contained  in  a  work  published  in  Philaddpliia  in  1827, 
entitled  "  Lessons  in  Practical  Anatomy."  , 


OCUI-AR  GROUP.  171 

the  sphenoid.  The  superciliary  portion  of  the  orbit  may  now  be 
driven  forwards  by  a  smart  blow,  and  the  broken  fragments  of  the 
roof  of  the  orbit  removed.  The  periosteum  will  then  be  exposed 
unbroken  and  undisturbed.  Remove  the  periosteum  from  the  whole 
of  the  upper  surface  of  the  exposed  orbit,  and  the  muscles  may  then 
be  examined. 

The  levator  'palpehrce  is  a  long,  thin,  and  triangular  muscle ;  it 
arises  from  the  upper  margin  of 
the  optic  foramen,  and  from  the  Fig.  79. 

fibrous  sheath  of  the  optic  nerve, 
and  is  inserted  into  the  upper 
border  of  the  superior  tarsal 
cartilage. 

Eelations. — By  its  dipper  sur- 
face with  the  fourth  nerve,  the  su- 
pra-orbital nerve  and  artery,  the 
periosteum  of  the  orbit,  and  in 
front  with  the  broad  tarsal  liga- 
ment. By  its  under  surface  it  rests  upon  the  superior  rectus  muscle, 
and  the  globe  of  the  eye ;  it  receives  its  nerve  and  artery  by  this 
aspect,  and  in  front  is  lined  for  a  short  distance  by  the  conjuiictiva. 

The  rectus  superior  (attollens)  arises  from  the  upper  margin  of  the 
optic  foramen,  and  from  the  fibrous  sheath  of  the  optic  nerve,  and  is 
inserted  into  the  upper  surface  of  the  globe  of  the  eye  at  a  point 
somewhat  more  than  three  lines  from  the  margin  of  the  cornea. 

Relations. — By  its  zipper  surface  with  the  levator  palpebree  mus- 
cle ;  and  by  the  under  surface  with  the  optic  nerve,  the  ophthalmic 
artery  and  nasal  nerve,  from  which  it  is  separated  by  a  layer  of 
fascia  and  by  the  adipose  tissue  of  the  orbit,  and  in  front  with  the 
globe  of  the  eye,  the  tendon  of  the  superior  oblique  muscle  being 
interposed. 

The  rectus  inferior  (depressor)  arises  from  the  inferior  margin 
of  the  optic  foramen  by  a  tendon  (ligament  of  Zinn)  which  is 
common  to  it,  the  internal  and  the  external  rectus,  and  from  the 
fibrous  sheath  of  the  optic  nerve ;  it  is  inserted  into  the  inferior  sur- 
face of  the  globe  of  the  eye  at  a  little  more  than  two  Unes  from  the 
margin  of  the  cornea. 

Relations. — By  its  upper  surface  with  the  optic  nerve,  the  infe- 
rior oblique  branch  of  the  third  nerve,  the  adipose  tissue  of  the 
orbit,  and  the  under  surface  of  the  globe  of  the  eye.     By  its  binder 

Fig.  79.  The  muscles  of  the  eyeball ;  the  view  is  taken  from  the  outer  side  of  the 
right  orbit.  1,  A  small  fragment  of  the  sphenoid  bone  around  the  entrance  of  the  optic 
nerve  into  the  orbit.  2.  The  optic  nerve.  3.  The  globe  of  the  eye.  4.  The  levator 
palpebrtE  muscle.  5.  The  superior  oblique  muscle.  6.  Its  cartilaginous  pulley.  7.  Its 
reflected^  tendon.  8.  The  inferior  oblique  muscle,  the  small  square  knob  at  its  com- 
mencement is  a  piece  of  its  bony  origin  broken  off.  9.  The  superior  rectus.  10.  The 
internal  rectus  almost  concealed  by  the  optic  nerve.  11.  Part  of  the  external  rectus, 
showing  its  two  heads  of  origin.  12.  The  extremity  of  the  external  rectus  at  its  in- 
sertion  ;  the  intermediate  portion  of  the  muscle  having  been  removed.  13.  The  inferior 
rectus.  14.  The  tunica  albuginea,  formed  by  the  expansion  of  the  tendons  of  the  four 
recti. 


172  KECTI  OBLiaUE. 

surface  with  the  periosteum  of  the  floor  of  the  orbit,  and  with  the 
inferior  obhqLie  muscle. 

The  rectus  internus  (adductor),  the  thickest  and  shortest  of  the 
straight  muscles,  arises  from  the  common  tendon,  and  from  the 
fibrous  sheath  of  the  optic  nerve;  and  is  inserted  mio  ihe  inner 
surface  of  the  globe  of  the  eye  at  two  lines  from  the  margin  of  the 
cornea. 

Relations. — By  its  internal  surface  with  the  optic  nerve,  the  adi- 
pose tissue  of  the  orbit  and  the  eyeball.  By  its  outer  surface  with 
the  periosteum  of  the  orbit,  and  by  its  upper  border  with  the  ante- 
rior and  posterior  ethmoidal  vessels,  the  nasal  and  supra-trochlear 
nerve. 

The  rectus  externus  (abductor),  the  longest  of  the  straight  mus- 
cles, ames  by  two  distinct  heads,  one  from  the  common  tendon,  the 
other  with  the  origin  of  the  superior  rectus  from  the  margin  of  the 
optic  foramen;  the  nasal,  third  and  sixth  nerves  passing  between  its 
heads.  It  is  inserted  into  the  outer  surface  of  the  globe  of  the  eye  at 
a  little  more  than  two  lines  from  the  margin  of  the  cornea. 

Relations. — By  its  internal  surface  with  the  third,  the  nasal,  the 
sixth,  and  the  optic  nerve,  the  ciliary  ganglion  and  nerves,  the  oph- 
thalmic artery  and  vein,  the  adipose  tissue  of  the  orbit,  the  inferior 
oblique  muscle,  and  the  eyeball.  By  its  external  surface  with  the 
periosteum  of  the  orbit;  and  by  the  upper  border  with  the  lach- 
rymal vessels  and  nerve  and  the  lachrymal  gland. 

The  recti  muscles  present  several  characters  which  are  common 
to  all :  thus,  they  are  [thin,  have  the  form  of  an  isosceles  triangle, 
bear  the  same  relation  to  the  globe  of  the  eye,  and  are  inserted  in 
a  similar  manner  into  the  sclerotica,  at  about  two  lines  from  the 
circumference  of  the  cornea.  The  points  of  difference  relate  to 
thickness  and  length;  the  internal  rectus  is  the  thickest  and  most 
short,  the  external  rectus  the  longest  of  the  four,  and  the  superior 
rectus  the  most  thin.  The  insertion  of  the  four  recti  muscles  into 
the  globe  of  the  eye  forms  a  tendinous  expansion,  which  is  continued 
as  far  as  the  margin  of  the  cornea,  and  is  called  the  tunica  albuginea. 

The  obliquus  superior  (trochlearis)  is  a  fusiform  muscle,  arising 
from  the  margin  of  the  optic  foramen  and  from  the  fibrous  sheath 
of  the  optic  nerve ;  it  passes  forwards  to  the  pulley  beneath  the 
internal  angular  process  of  the  frontal  bone ;  its  tendon  is  then 
reflected  beneath  the  superior  rectus  muscle,  to  the  outer  and  poste- 
rior part  of  the  globe  of  the  eye,  where  it  is  inserted  into  the 
sclerotic  coat,  near  the  entrance  of  the  optic  nerve.  The  tendon  is 
surrounded  by  a  synovial  membrane,  while  passing  through  the 
cartilaginous  pulley. 

Relations. — By  its  superior  surface  with  the  fourth  nerve,  the 
supra-trochlear  nerve,  and  with  the  periosteum  of  the  orbit.  By  the 
inferior  surface  with  the  adipose  tissue  of  the  orbit,  the  upper 
border  of  the  internal  rectus,  and  the  vessels  and  nerves  in  rela- 
tion with  that  border. 

The  obliijuus  inferior,  a  thin  and  narrow  muscle,  arises  from  the 
inner  margin  of  the' superior  maxillary  bone,  immediately  external 


NASAL  GROUP.  173 

to  the  lachrymal  groove,  and  passes  beneath  the  inferior  rectus,  to 
be  inserted  into  the  outer  and  posterior  part  of  the  eyeball,  at  about 
two  lines  from  the  entrance  of  the  optic  nerve. 

Relations. — By  its  superior  surface  with  the  inferior  rectus  muscle 
and  with  the  eyeball;  and  by  the  inferior  surface  with  the  perios- 
teum of  the  floor  of  the  orbit  and  the  external  rectus  muscle. 

According  to  Mr.  Ferrall*  the  muscles  of  the  orbit  are  separated 
from  the  globe  of  the  eyeball  and  from  the  structures  immediately 
surrounding  the  optic  nerve,  by  a  distinct  fascia,  which  is  continuous 
with  the  broad  tarsal  ligament  and  with  the  tarsal  cartilages.  This 
fascia  the  author  terms,  the  tunica  vaginalis  oculi  ;-\  it  is  pierced 
anteriorly  for  the  passage  of  the  six  orbital  muscles  by  six  openings, 
through  which  the  tendons  of  the  muscles  play  as  through  pulleys. 
The  use  assigned  to  it  by  Mr.  Ferrall  is  to  protect  the  eyeball  from 
the  pressure  of  its  muscles  during  their  action.  By  means  of  this 
structure  the  recti  muscles  are  enabled  to  impress  a  rotatory  move- 
ment upon  the  eyeball ;  and  in  animals  provided  with  a  retractor 
muscle,  they  also  act  as  antagonists  to  its  action. 

Actions. — The  levator  palpebrse  raises  the  upper  eyelid.  The  four 
recti,  acting  singly,  pull  the  eyeball  in  the  four  directions  of  upwards, 
downwards,  inwards,  and  outwards.  Acting  by  pairs,  they  carry 
the  eyeball  in  the  diagonal  of  these  directions,  viz.  upwards  and 
inwards,  upwards  and  outwards,  downwards  and  inwards,  or 
downwards  and  outwards.  Acting  altogether,  they  directly  retract 
the  globe  within  the  orbit.  The  superior  oblique  muscle,  acting 
alone,  rolls  the  globe  inwards  and  forwards,  and  carries  the  pupil 
outwards  and  downwards  to  the  lower  and  outer  angle  of  the  orbit. 
The  inferior  oblique,  acting  alone,  rolls  the  globe  outwards  and 
backwards,  and  carries  the  pupil  outwards  and  upwards  to  the 
upper  and  outer  angle  of  the  eye.  Both  muscles  acting  together, 
draw  the  eyeball  forwards,  and  give  the  pupil  that  slight  degree  of 
e version  which  enables  it  to  admit  the  largest  field  of  vision. 

4.  JVasal  group. — Pyramidalis  nasi.J 
Compressor  nasi. 

The  pyramidalis  nasi  is  a  small  pyramidal  slip  of  muscular  fibres 
sent  downwards  upon  the  nose  by  the  occipito-frontalis.  It  is 
inserted  into  the  tendinous  expansion  of  the  compressores  nasi. 

Relations. — By  its  upper  surface  with  ihe  integument;  by  its 
under  surface  with  the  periosteum  of  the  nasal  bone.  Its  outer 
border  corresponds  with  the  edge  of  the  orbicularis  palpebrarum, 
and  its  inner  border  with  its  fellow,  from  which  it  is  separated  by 
a  slight  interval. 

The  coiupressor  nasi  is  a  thin  and  triangular  muscle  ;  it  arises  by 
its  apex  from  the  canine  fossa  of  the  superior  maxillary  bone,  and 

*  In  a  paper  read  before  tlie  Royal  Society,  on  the  10th  of  June,  1841. 
t  This  fascia  was  first  described  by  Mr.  Dalryrnple  in  his  work  on  the  "  Anatomy 
of  the  Human  Eye."     1834. 

\  This  is  described  by  Horner  as  one  of  the  insertions  of  the  occipito-frontalis. — G. 

15* 


174  SUPERIOR  LABIAL  GROUP. 

spreads  out  upon  the  side  of  the  nose  into  a  thin  tendinous  expan- 
sion, which  is  continuous  across  its  ridge  with  the  muscle  of  the 
opposite  side. 

Relations. — By  its  superficial  surface  with  the  levator  labii  supe- 
rioris  proprius,  the  levator  labii  superioris  alceque  nasi,  and  the  inte- 
gument ;  by  its  dee-p  surface  with  the  superior  maxillary  and  nasal 
bone,  and  with  the  alar  and  lateral  cartilages  of  the  nose. 

Actions. — The  pyramidalis  nasi,  as  a  point  of  attachment  of  the 
occipito-frontalis,  assists  that  muscle  in  its  action:  it  also  draws 
down  the  inner  angle  of  the  eyebrow,  and  by  its  insertion  fixes  the 
aponeurosis  of  the  compressores  nasi.  The  compressores  nasi 
appear  to  act  in  expanding  rather  than  in  compressing  the  nares ; 
hence  probably  the  compressed  state  of  the  nares  from  paralysis  of 
these  muscles  in  the  last  moments  of  life,  or  in  compression  of  the 
brain. 

5.  Superior  Labial  group. — Orbicularis  oris, 

Levator  labii  superioris  alseque  nasi, 
Levator  labii  superioris  proprius,* 
Levator  anguli  oris, 
Zygomaticus  major, 
Zygomaticus  minor, 
Depressor  labii  superioris  alsequenasi. 

The  orbicularis  oris  is  a  sphincter  muscle,  completely  surrounding 
the  mouth,  and  possessing  consequently  neither  origin  nor  insertion. 
It  is  composed  of  two  thick  semicircular  planes  of  fibres,  which  em- 
brace the  rima  of  the  mouth,  and  interlace  at  their  extremities, 
where  they  are  continuous  v>'ith  the  fibres  of  the  buccinator,  and  of 
the  other  muscles  connected  with  the  angle  of  the  mouth.  The 
upper  segment  is  attached  by  means  of  a  small  muscular  fasciculus 
(naso-labialis)  to  the  columna  of  the  nose. 

Relations. — By  its  superficial  surface  with  the  integument  of  the 
lips,  with  which  it  is  closely  connected.  By  its  deep  surface  with 
the  mucous  membrane  of  the  mouth,  the  labial  glands  and  coronary 
arteries  being  interposed.  By  its  circumference  with  the  numerous 
muscles  which  move  the  lips,  and  by  the  inner  border  with  the 
mucous  membrane  of  the  rima  of  the  mouth. 

Thelevator  labii  superioris  alccgue  nasi  is  a  thin  triangular  muscle ; 
it  arises  from  the  nasal  process  of  the  superior  maxillary  bone  ;  and, 
becoming  broader  as  it  descends,  is  inserted  by  two  distinct  por- 
tions into  the  integument  of  the  ala  of  the  nose  and  upper  h'p. 

Relations. — By  its  superficial  surface  with  a  part  of  the  orbicularis 
palpebrarum  muscle,  the  facial  artery,  and  the  integument.  By  its 
deep  surface  with  the  compressor  nasi  and  alar  cartilage. 

The  levator  labii  superioris  proprius  is  a  thin  quadrilateral  muscle  ; 
it  arises  from  the  lower  border  of  the  orbit,  and  is  inserted  into  the 
integument  of  the  upper  lip. 

Relations. — By  its  superficial  surface  with  the  lower  segment  of 

*  These  two  levators  arc  described  as  one  by  Horner. — G. 


SUPERIOR  LABIAL  GROUP.  175 

the  orbicularis  palpebrarum,  with  the  facial  artery,  and  with  the 
integument.  By  its  deep  surface  with  the  origins  of  the  compressor 
nasi  and  levator  anguli  oris  muscle,  and  with  the  infra-orbital  artery 
and  nerve. 

The  levator  anguli  oris  arises  from  the  canine  fossa  of  the  supe- 
rior maxillary  bone,  and  passes  outwards  to  be  inserted  into  the 
ancrle  of  the  mouth,  intermingHng  its  fibres  with  those  of  the  orbicu- 
laris, zygomatici  and  depressor  anguli  oris. 

Relations. — By  its  superficial  surface  with  the  levator  labii  supe- 
rioris  proprius,  the  branches  of  the  infra-orbital  artery  and  nerve, 
and  inferiorly  with  the  integument.  By  its  deep  surface  with  the 
superior  maxillary  bone  and  buccinator  muscle. 

The  zygomatic  muscles  are  two  slender  fasciculi  of  fibres  which 
arise  from  the  malar  bone,  and  are  inserted  into  the  angle  of  the 
mouth,  where  they  are  continuous  with  the  other  muscles  attached 
to  this  part.  The  zygomaticus  minor  is  situated  in  front  of  the 
major,  and  is  continuous  at  its  insertion  with  the  levator  labii  supe- 
rioris  proprius  ;  it  is  not  unfrequently  wanting. 

Relations. — The  zijgomaticus  major  muscle  is  in  relation  by  its 
superficial  surface  with  the  lower  segment  of  the  orbicularis  palpe- 
brarum above,  and  the  fat  of  the  cheek  and  integument  for  the  rest 
of  its  extent.  By  its  deep  surface  with  the  malar  bone,  the  masseter, 
and  buccinator  muscle,  and  the  facial  vessels.  The  zygomaticus 
minor  being  in  front  of  the  major,  has  no  relation  with  the  masseter 
muscle,  while  inferiorly  it  rests  upon  the  levator  anguli  oris. 

The  depressor  labii  superioris  alceque  nasi  (myrtiformis)  is  seen 
by  drawing  upwards  the  upper  lip,  and  raising  the  mucous  mem- 
brane. It  is  a  small  oval  slip  of  muscle,  situated  at  each  side  of  the 
fraenum,  arising  from  the  incisive  fossa,  and  passing  upwards  to  be 
inserted  into  the  upper  lip  and  ala  of  the  nose.  This  muscle  is  con- 
tinuous by  its  outer  border  with  the  edge  of  the  compressor  nasi. 

Relations. — By  its  superficial  surface  with  the  mucous  membrane 
of  the  mouth,  the  orbicularis  oris  and  levator  labii  superiofis  alaeque 
nasi  muscle ;  and  by  its  deep  surface  with  the  superior  maxillary 
bone. 

Actions. — The  orbicularis  oris  produces  the  direct  closure  of  the 
lips  by  means  of  its  continuity  at  the  angles  of  the  mouth,  with  the 
fibres  of  the  buccinator.  When  acting  singly  in  the  forcible  closure 
of  the  mouth,  the  integument  is  thrown  into  wrinkles  in  consequence 
of  its  firm  connexion  with  the  surface  of  the  muscle.  The  levator 
labii  superioris  alasque  nasi  lifts  the  upper  lip  with  the  ala  of  the  nose, 
and  expands  the  opening  of  the  nares.  The  depressor  labii  superioris 
alajque  nasi  is  the  antagonist  to  this  muscle,  drawing  the  upper  lip 
and  ala  of  the  nose  downwards,  and  diminishing  the  opening  of  the 
nares.  The  levator  labii  superioris  proprius  is  the  proper  elevator 
of  the  upper  lip;  acting  singly,  it  draws  the  lip  a  little  to  one  side. 
The  levator  anguli  oris  lifts  the  angle  of  the  mouth  and  draws  it 
inv^'ards,  while  the  zygomatici  pull  it  upwards  and  outwards,  as  in 
laughing. 


176  MAXILLARSr  GROUP. 

6.  Inferior  Labial  group. — Depressor  labii  inferiqris, 

Depressor  anguli  oris, 
Levator  labii  inferioris. 

Dissection. — To  dissect  the  inferior  labial  region,  continue  the  ver- 
tical section  from  the  margin  of  the  lower  lip  to  the  point  of  the 
chin.  Then  carry  an  incision  along  the  margin  of  the  lower  jaw  to 
its  angle.  Dissect  off  the  integument  and  superficial  fascia  from  the 
whole  of  this  surface,  and  the  muscles  of  the  inferior  labial  region 
will  be  exposed. 

The  depressor  labii  infeinoris  (quadratus  menti)  arises  from  the 
oblique  line  by  the  side  of  the  symphysis  of  the  lower  jaw,  and  pass- 
ing upwards  and  inwards  is  insertedmio  the  orbicularis  muscle  and 
integument  of  the  lower  lip. 

Relations. — By  its  superficial  surface  with  a  part  of  the  depressor 
anguli  oris,  and  with  the  integument  of  the  chin,  with  which  it  is 
closely  connected.  By  the  deep  surface  with  the  levator  labii  in- 
ferioris, the  labial  glands  and  mucous  membrane  of  the  lower  lip, 
and  with  the  mental  nerve  and  artery. 

The  depressor  anguli  oris  (triangularis  oris)  is  a  triangular  plane  of 
muscle,  arising  by  a  broad  base  from  the  external  oblique  ridge  of  the 
lower  jaw,  and  inserted  by  its  apex  into  the  angle  of  the  mouth,  where 
it  is  continuous  with  the  levator  anguli  oris  and  zygomaticus  major. 

Relations. — By  its  superficial  surface  with  the  integument,  and  by 
its  deep  surface  with  the  depressor  labii  inferioris,  the  platysma  my- 
oides,the  buccinator  and  the  branches  of  the  mental  nerve  and  artery. 

The  levator  labii  inferioris  (levator  menti)  is  a  small  conical  slip 
of  muscle,  arising  from  the  incisive  fossa  of  the  lower  jaw,  and 
inserted  into  the  integument  of  the  chin.  It  is  in  relation  with  the 
mucous  membrane  of  the  mouth,  with  its  fellow,  and  with  the 
depressor  labii  inferioris. 

Actions. — The  depressor  labii  inferioris  draws  the  lower  lip  di- 
rectly downwards,  and  at  the  same  time  a  little  outwards.  The 
depressor  anguli  oris,  from  the  radiate  direction  of  its  fibres,  will  pull 
the  angle  of  the  mouth  either  downwards  and  inwards,  or  down- 
wards and  outwards,  and  be  expressive  of  grief;  or  acting  with  the 
levator  anguli  oris  and  zygomaticus  major,  it  will  draw  the  angle 
of  the  mouth  directly  backwards.  The  levator  labii  inferioris  raises 
and  protrudes  the  integument  of  the  chin. 

7.  Maxillary  Group. — Masseter, 

Temporalis, 
Buccinator, 
Pterygoideus  externus, 
Pterygoideus  internus. 

Dissection. — The  masseter  has  been  already  exposed  by  the  pre- 
ceding dissection. 

The  masseter  (p.atfrfaofxai,  to  chew,)  is  a  short  and  thick  and  some- 
what quadrilateral  muscle,  composed  of  two  planes  of  fibres,  super- 
ficial and  deep.     The  superficial  layer  anises  by  a  strong  aponeuro- 


MAXILLAE Y  GROUP.  177 

sis  from  the  tuberosity  of  the  superior  maxillary  bone,  and  from  the 
lower  border  of  the  malar  bone  and  zygoma,  and  passes  backwards 
to  be  inserted  into  the  ramus  and  angle  of  the  inferior  maxilla.  The 
deep  layer  arises  from  the  posterior  part  of  the  zygoma,  and  passes 
forwards,  to  be  inserted  into  the  upper  half  of  the  ramus.  This 
muscle  is  tendinous  and  muscular  in  its  structure. 

Relations. — By  its  external  surface  with  the  zygomaticus  major 
and  risorius  Santorini  muscle,  the  parotid  gland  and  Stenon's  duct, 
the  transverse  facial  artery,  the  pes  anserinus  and  the  integument. 
By  its  internal  surface  with  the  temporal  musclej  the  buccinator, 
from  which  it  is  separated  by  a  large  mass  of  fat,  and  with  the 
ramus  of  the  lower  jaw.  By  its  posterior  border  with  the  parotid 
gland  ;  and  by  the  anterior  border  with  the  facial  artery  and  vein. 

Dissection. — Make  an  incision  along  the  upper  border  of  the 
zygoma,  for  the  purpose  of  separating  the  temporal  fascia  from  its 
attachment.  Then  saw  through  the  zygomatic  process  of  the  malar 
bone,  and  through  the  root  of  the  zygoma,  near  to  the  meatus  audi- 
torius.  Draw  down  the  zygoma,  and  with  it  the  origin  of  the  mas- 
seter,  and  dissect  the  latter  muscle  away  from  the  ramus  and  angle 
of  the  inferior  maxilla.  Now  remove  the  temporal  fascia  from  the 
rest  of  its  attachment,  and  the  whole  of  the  temporal  muscle  will  be 
exposed. 

The  temporal  is  a  broad  and  radiating  muscle,  occupying  a  consi- 
derable extent  of  the  side  of  the  head  and  filling  the  temporal  fossa. 
It  is  covered  in  by  a  very  dense  fascia  (temporal  fascia),  which  is 
attached  along  the  temporal  ridge  on  the  side  of  the  skull,  extending 
from  the  external  angular  process  of  the  frontal  bone  to  the  mastoid 
portion  of  the  temporal ;  inferiorly,  it  is  connected  to  the  upper 
border  of  the  zygoma.  The  muscle  arises  by  tendinous  fibres  from 
the  whole  length  of  the  temporal  ridge,  and  by  muscular  fibres  from 
the  temporal  fascia  and  from  the  entire  surface  of  the  temporal 
fossa.  Its  fibres  converge  to  a  strong  and  narrow  tendon,  which  is 
inserted  into  the  apex  of  the  coronoid  process,  and  for  some  way 
down  upon  its  inner  surface. 

Relations, — By  its  external  surface  with  the  temporal  fascia, 
which  separates  it  from  the  attollens  and  attrahens  aurem  muscle, 
the  temporal  vessels  and  nerves;  and  with  the  zygoma  and  masseter. 
By  its  internal  surface  with  the  bones  forming  the  temporal  fossa, 
the  external  pterygoid  muscle,  a  part  of  the  buccinator,  and  the  in- 
ternal maxillary  artery,  with  its  deep  temporal  branches. 

By  sawing  through  the  coronoid  process  near  to  its  base,  and  pull- 
ing it  upwards,  together  with  the  temporal  muscle,  which  may  be 
dissected  from  the  fossa,  we  obtain  a  view  of  the  entire  extent  of  the 
buccinator  and  of  the  external  pterygoid  muscle. 

The  buccinator  {buccina,  a  trumpet),  the  trumpeter's  muscle, 
arises  from  the  alveolar  process  of  the  superior  maxillary  and  from 
the  external  oblique  line  of  the  inferior  maxillary  bone,  as  far  for- 
ward as  the  second  bicuspid  tooth,  and  from  the  pterygo-maxillary 
ligament.  This  ligament  is  the  raphe  of  union  between  the  bucci- 
nator and  superior  constrictor  muscle,  and  is  attached  by  one  extra- 


178 


MAXILLARY  GROUP. 


mity  to  the  hamular  process  of  the  internal  pterygoid  plate,  and  by 
the  other  to  the  extremity  of  the  molar  ridge.  The  fibres  of  the 
muscle  converge  towards  the  angle  of  the  mouth  where  they  cross 
each  other,  the  superior  being  continuous  with  the  inferior  segment 
of  the  orbicularis  oris,  and  the  inferior  with  the  superior  segment. 
The  muscle  is  invested  externally  by  a  thin  fascia. 

Relations. — By  its  external  surface,  posteriorly  with  a  large  and 
rounded  mass  of  fat,  which  separates  the  muscle  from  the  ramus  of 
the  lower  jaw,  the  temporal,  and  the  masseter  ;  anteriorly  with  the 
risorius  Santoririi,  the  zygomatici,  the  levator  anguli  oris,  and  the 
depressor  anguli  oris.  It  is  also  in  relation  with  a  part  of  Stenon's 
duct,  which  pierces  it  opposite  to  the  second  molar  tooth  of  the 
upper  jaw,  with  the  transverse  facial  artery,  the  branches  of  the 
facial  and  buccal  nerve,  and  the  facial  artery  and  vein.  By  its 
internal  surface  with  the  buccal  glands  and  mucous  membrane  of 
the  mouth. 

The  external  -pterygoid  is  a  short  and  thick  muscle,  broader  at 
its  origin  than  at  its  insertion.  It  arises  by  two  heads,  one  from 
the  pterygoid  ridge  on  the  great  ala  of  the  sphenoid  ;  the  otiier  from 
the  external  pterygoid  plaie  and  tuberosity  of  the  palate  bone.  The 
fibres  pass  backwards  to  be  inserted  into  the  neck  of  the  lower  jaw 
and  the  interarticular  fibro-cartilage.  The  internal  maxillary  artery 
frequently  passes  between  the  two  heads  of  this  muscle. 

Relations. — By  its  external  surface  with  the  ramus  of  the  lower 
jaw,  the  temporal  muscle,  and  internal  maxillary  artery ;  by  its 

internal  surface  with  the  internal 
pterygoid  muscle,  and  the  inferior 
maxillary  nerve;  and  by  its  upper 
border  with  the  muscular  branches  of 
the  inferior  maxillary  nerve ;  the  in- 
ternal maxillary  artery  passes  between 
the  two  heads  of  this  muscle,  and  its 
lower  origin  is  pierced  by  the  buccal 
nerve. 

The  external  pterygoid  muscle  must 
now  be  removed,  the  ramus  of  the 
lower  jaw  sawn  through  its  lower 
third,  and  the  head  of  the  bone  dislo- 
cated from  its  socket  and  withdrawn,  for  the  purpose  of  seeing  the 
pterygoideus  internus. 

The  internal  pterygoid  is  a  thick  quadrangular  muscle.  It  arises 
from  the  pterygoid  fossa,  and  descends  obliquely  backwards,  to  be 
inserted  into  the  ramus  and  angle  of  the  lower  jaw;  it  resembles 
the  masseter  in  appearance  and  direction,  and  was  named  by 
Winslow  the  internal  masseter. 

Relations. — By  its  external  surface  with  the  internal  pterygoid, 

Fig.  80.  The  two  pterygoid  muscles.  The  zyjoromatic  arch  and  greater  part  of  the 
ramus  of  the  lower  jaw  have  hcen  removed  in  order  to  bring  these  muscles  into  view. 
1.  The  sphenoid  origin  of  the  external  pterygoid  muscle.  2.  Its  pterygoid  origin,  3. 
Tlie  internal  pterygoid  muscle. 


Fiff.  80. 


AURICULAR  GROUP.  179 

the  inferior  maxillary  nerve  and  its  branches,  the  internal  maxillary 
artery  and  branches,  the  internal  lateral  ligament,  and  the  ramus  of 
the  lower  jaw.  By  its  internal  surface  with  the  tensor  palati  and 
superior  constrictor  of  the  pharynx  with  its  fascia  ;  and  by  its  pos- 
terior border  with  the  parotid  gland. 

Actions. — The  maxillary  muscles  are  the  active  agents  in  masti- 
cation, and  form  an  apparatus  beautifully  fitted  for  that  office.  The 
buccinator  circumscribes  the  cavity  of  the  mouth,  and  with  the  aid 
of  the  tongue  keeps  the  food  under  the  immediate  pressure  of  the 
teeth.  By  means  of  its  connexion  with  the  superior  constrictor,  it 
shortens  the  cavity  of  the  pharynx,  from  before  backwards,  and 
becomes  an  important  auxiliary  in  deglutition.  The  temporal,  the 
masseter,  and  the  internal  pterygoid  are  the  bruising  muscles,  draw- 
ing the  lower  jaw  against  the  upper  with  great  force.  The  two 
latter,  by  the  obliquity  of  their  direction,  assist  the  external  ptery- 
goid in  grinding  the  food  by  carrying  the  lower  jaw  forward  upon 
the  upper ;  the  jaw  being  brought  back  again  by  the  deep  portion 
of  the  masseter  and  posterior  fibres  of  the  temporal.  The  whole  of 
these  muscles,  acting  in  succession,  produce  a  rotatory  movement 
of  the  teeth  upon  each  other,  which,  with  the  direct  action  of  the 
lower  jaw  against  the  upper,  effects  the  proper  mastication  of  the 
food. 

8.  Auricular  Group. — Attollens  aurem, 
Attrahens  aurem, 
Retrahens  aurem. 

Dissection. — The  three  small  muscles  of  the  ear  may  be  exposed 
by  removing  a  square  of  integument  from  around  the  auricula. 
This  operation  must  be  performed  with  care,  otherwise  the  muscles, 
which  are  extremely  thin,  will  be  raised  with  the  superficial  fascia. 

The  attollens  aurem  (superior  auris),  the  largest  of  the  three,  is  a 
thin  triangular  plane  of  muscular  fibres,  arising  from  the  edcre  of 
the  aponeurosis  of  the  occipito-frontalis,  and  inserted  into  the  upper 
part  of  the  concha. 

It  is  in  relation  by  its  external  surface  with  the  integument,  and 
by  the  internal  with  the  temporal  aponeurosis. 

The  attrahens  aurem  (anterior  auris),  also  triangular,  arises  from 
the  edge  of  the  aponeurosis  of  the  occipito-frontalis,  and  is  inserted 
into  the  anterior  part  of  the  concha,  covering  in  the  anterior  and 
posterior  temporal  arteries. 

It  is  in  relation  by  its  external  surface  with  the  integument,  and 
by  the  internal  with  the  temporal  aponeurosis  and  with  the  temporal 
artery  and  veins. 

The  retrahens  aurem  (posterior  auris),  arises  by  three  or  four 
muscular  slips  from  the  mastoid  process.  They  are  inserted  into 
the  posterior  surface  of  the  concha. 

It  iim  relation  by  its  external  surface  with  the  integument,  and 
by  its  mternal  surface  with  the  mastoid  portion  of  the  temporal  bone. 

Actions. — The  muscles  of  the  auricular  region  possess  but  little 


180 


MUSCLES  OF  THE  NECK. 


action  in  man;  they  are  the  analogues  of  important  muscles  in 
brutes.     Their  use  is  sufficiently  explained  by  their  names. 

Muscles  of  the  Neck. — The  muscles  of  the  neck  may  be  arranged 
into  eicrht  groups,  corresponding  with  the  natural  divisions  of  the 
region";  they  are  the — 

1.  Superficial  group. 

2.  Depressors  of  the  os  hyoides  and  larynx. 

3.  Elevators  of  the  os  hyoides  and  larynx. 

4.  Lingual  group. 

5.  Pharyngeal  group. 

6.  Soft  palate  group. 

7.  Prsevertebral  group. 

8.  Proper  muscles  of  the  larynx. 


And  each  of  these  gilDups  consist 

1.  Superficial  Group.  * 

Platysma  myoides, 
Sterno-cleido-mastoideus. 

2.  Depressors  of  the  os 
hyoides  and  larynx. 

Sterno-hyoideus, 
Sterno-thyroideus, 
Thyro-hyoideus, 
Omo-hyoideus. 

3.  Elevators  of  the  os 
hyoides  and  larynx. 

Digastricus, 

Stylo-hyoideus, 

Mylo-hyoideus, 

Genio-hyoideus, 

Genio-hyo-glossus. 

4.  Muscles  of  the  tongue. 

Genio-hyo-glossus, 

Hyo-glossus, 

Lingualis, 

Stylo-glossus, 

Palato-glossus.* 


of  the  following  muscles: — viz. 

5.  Muscles  of  the  pharynx. 

Constrictor  inferior, 
Constrictor  medius, 
Constrictor  superior, 
Stylo-pharyngeus, 
Palato-pharyngeus. 

6.  Muscles  of  the  soft  Palate. 

Levator  palati, 
Tensor  palati, 
Azygos  uvulae, 
Palato-glossus,* 
Palato-pharyngeus. 

7.  PrcBvertebral  Group. 

Rectus  anticus  major, 
Rectus  anticus  minor, 
Scalenus  anticus. 
Scalenus  posticus, 
Longus  colli. 

8.  Muscles  of  the  Larynx. 

Crico-thyroideus, 
Crico-arytcenoideus,  posticus, 
Crico-arytffinoideus,  lateralis, 
Thyro-arytecnoideus, 
Arytsenoideus. 


Dmec^ww.— The  dissection  of  the  neck  should  be  commenced  by 
making  an  incision  along  the  middle  line  of  the  neck  from  the  chin 
to  the  "sternum,  and  bounding  it  superiorly  and  inferiorly  by  two 


*  Described  by  Horner  as  the  Constrictor  isthmii  faucium.—G. 


STERNO-CLEIDO  MASTOIDEUS.  181 

transverse  incisions ;  the  superior  one  being  carried  along  the 
margin  of  the  lower  jaw,  and  across  the  mastoid  process  to  the 
tubercle  on  the  occipital  bone,  the  inferior  one  along  the  clavicle  to 
the  acromion  process.  The  square  flap  of  integument  thus  included 
should  be  turned  back  from  the  entire  side  of  the  neck,  which  brings 
into  view  the  superficial  fascia,  and  on  the  removal  of  a  thin  layer 
of  it  the  platysma  myoides  will  be  exposed. 

The  j)Iatysma  myoides  (irXarvs,  (xuj,  sTSog,)  broad  muscle-like  lamella, 
is  a  thin  plane  of  muscular  fibres,  situated  between  the  two  layers 
of  the  superficial  cervical  fascia  ;  it  arises  from  the  integument  over 
the  pectoralis  major  and  deltoid  muscles,  and  passes  obliquely  up- 
wards and  inwards  along  the  side  of  the  neck  to  be  inserted  into 
the  side  of  the  chin,  oblique  line  of  the  lower  jaw,  the  angle  of  the 
mouth,  and  into  the  cellular  tissue  of  the  face.  The  most  anterior 
fibres  are  continuous  beneath  the  chin,  with  the  muscle  of  the  op- 
posite side  ;  the  next  interlace  with  the  depressor  anguli  oris,  and 
depressor  labii  inferioris,  and  the  most  posterior  fibres  are  disposed 
in  a  transverse  direction  across  the  side  of  the  face,  arising  in  the 
cellular  tissue  covering  the  parotid  gland,  and  inserted  into  the 
angle  of  the  mouth,  constituting  the  risorius  Santorini.  The  entire 
muscle  is  analogous  to  the  cutaneous  muscle  of  brutes,  the  pannicu- 
lus  carnosus. 

Relations. — By  its  external  surface  with  the  integument,  with 
which  it  is  closely  adherent  below,  but  loosely  above.  By  its  internal 
surface,  below  the  clavicle,  with  the  pectoralis  major  and  deltoid  ; 
in  the  neck,  with  the  external  jugular  vein  and  deep  cervical  fascia  ; 
on  the  face,  with  the  parotid  gland,  the  masseter,  the  facial  artery 
and  vein,  the  buccinator,  the  depressor  anguli  oris,  and  the  depres- 
sor labii  inferioris. 

On  raising  the  platysma  throughout  its  whole  extent,  the  sterno- 
mastoid  is  brought  into  view. 

The  sterno-cleido-mastoid  is  the  largest  oblique  muscle  of  the 
neck,  and  is  situated  between  two  layers  of  the  deep  cervical  fascia. 
It  arises,  as  implied  in  its  name,  from  the  sternum  and  clavicle 
(xksiSiov),  and  passes  obliquely  upwards  and  backwards  to  be  inserted 
into  the  mastoid  process  and  into  the  superior  curved  line  of  the 
occipital  bone.  The  sternal  portion  arises  by  a  rounded  tendon, 
increases  in  breadth  as  it  ascends,  and  spreads  out  to  a  considerable 
extent  at  its  insertion.  The  clavicular  portion  is  broad  and  fleshy, 
and  separate  from  the  sternal  portion  below,  but  becomes  gradually 
blended  with  its  posterior  surface  as  it  ascends. 

Relations. — By  its  sxiperficial  surface  with  the  integument,  the 
platysma  myoides,  the  external  jugular  vein,  superficial  branches  of 
the  anterior  cervical  plexus  of  nerves,  and  the  anterior  layer  of  the 
deep  cervical  fascia.  By  its  deep  surface  with  the  deep  layer  of 
the  cervical  fascia ;  with  the  sterno-clavicular  articulation,  the 
sterno-hyoid,  sterno-thyroid,  omo-hyoid,  scaleni,  levator  anguli 
scapulee,  splenii,  and  posterior  belly  of  the  digastric  muscle;  with 
the  phrenic  nerve,  and  the  posterior,  and  supra-scapular  artery;  with 

16 


182 


STERNOCLEIDO-MASTOIDEUS. 


the  deep  lymphatic  glands,  the  sheath  of  the  common  carotid  artery 
and  internal  juofular  vein,  the  descendens  noni  nerve,  the  external 
carotid  artery  and  its  posterior  branches,  the  commencement  of  the 
internal  carotid  artery;  with  the  cervical  plexus  of  nerves,  the 
pneurnogastric,  the  spinal  accessory,  the  hypoglossal,  the  sympa- 
thetic and  the  facial  nerve,  and  with  the  parotid  gland.  It  is 
pierced  on  this  aspect  by  the  spinal  accessory  nerve  and  by  the 

Fig.  81. 


branches  of  the  mastoid  artery.  The  anterior  border  of  the  muscle 
is  the  posterior  boundary  of  the  great  anterior  triangle,  the  other 
two  boundaries  being  the  middle  line  of  the  neck  in  front,  and  the 
lower  border  of  the  jaw  above.  It  is  the  guide  to  the  operations 
for  the  ligature  of  the  common  carotid  artery  and  arteria  innomi- 
nata,  and  for  oesophagotomy.  The  posterior  harder  is  the  anterior 
boundary  of  the  great  posterior  triangle  ;  the  other  two  boundaries 
being  the  anterior  border  of  the  trapezius  behind,  and  the  clavicle 
below. 

Actions. — The  platysma  produces  a  muscular  traction  on  the 
integument  of  the  neck,  which  prevents  it  from  falling  so  flaccid  in 

Fig.  81.  The  muscles  of  the  anterior  aspect  of  the  neck ;  on  the  left  side  the  super- 
ficial muscles  are  seen,  and  on  tlic  right  the  deep.  1.  The  posterior  belly  of  the  dig-as- 
tricus  muscle.  2.  Its  anterior  belly.  The  aponeurotic  pulley,  through  wiiich  its  tendon  is 
seen  passiny-,  is  attached  to  the  body  of  the  os  hyoides  3.  4.  The  stylo-hyoideus  mus- 
cle,  transfixed  by  the  posterior  belly  of  the  digastricus.  5.  Tlie  mylo-hyoideus.  6. 
The  genio-hyoideus.  7.  The  tongue.  8.  The  hyo-glossus.  9.  The  stylo-glossus. 
10.  The  stylo-pharyngeus.  11.  The  sterno-mastoid  muscle.  12.  Its  sternal  origin. 
13.  Its  clavicular  origin.  14.  The  sterno-hyoid.  15.  The  sterno-thyroid  of  the  right 
side.  If).  The  thyrohyoid.  17.  The  hyoid  portion  of  the  omo-hyoid.  18,  18.  Its 
scapular  portion  ;  on  the  left  side,  the  tendon  of  the  muscle  is  seen  to  be  bound  down 
by  a  portion  of  the  deep  cervical  fascia.  19.  The  clavicuhir  portion  of  the  trapezius 
20.  The  scalenus  anticus,  of  the  right  side.    21.  The  scalenus  posticus. 


DEPRESSORS  OF  THE  OS  HYOIDES  AND  LARYNX.  183 

old  persons  as  would  be  the  case  if  the  extension  of  the  skin  were 
the  mere  result  of  elasticity.  It  draws  also  upon  the  angle  of  the 
mouth,  and  is  one  of  the  depressors  of  the  lower  jaw.  The  trans- 
verse fibres  draw  the  angle  of  the  mouth  outwards  and  slightly 
upwards.  The  sterno-mastoid  muscles  are  the  great  anterior  mus- 
cles of  connexion  between  the  thorax  and  the  head.  Both  mus- 
cles acting  together  will  bow  the  head  directly  forwards.  The 
clavicular  portions,  acting  more  forcibly  than  the  sternal,  give 
stability  and  steadiness  to  the  head  in  supporting  great  weights. 
Either  muscle  acting  single  would  draw  the  head  towards  the 
shoulder  of  the  same  side,  and  carry  the  face  towards  the  opposite 
side. 

Second  Group. — Depressors  of  the  Os  Hyoides  and  Larynx. 

Sterno-hyoid, 
Sterno-thyroid, 
Thyro-hyoid, 
Omo-hyoid. 

Dissection. — These  muscles  are  brought  into  view  by  removing 
the  deep  fascia  from  off  the  front  of  the  neck  between  the  two 
sterno-mastoid  muscles.  The  omo-hyoid  to  be  seen  in  its  whole 
extent  requires  that  the  sterno-mastoid  muscle  be  divided  from  its 
origin  and  turned  aside. 

The  sterno-hyoideus  is  a  narrow  riband-like  muscle,  arising  from 
the  posterior  surface  of  the  first  bone  of  the  sternum  and  inner  ex- 
tremity of  the  clavicle.  It  is  inserted  into  the  lower  border  of  the 
body  of  the  os  hyoides.  The  sterno-hyoidei  are  separated  by  a  con- 
siderable interval  at  the  root  of  the  neck,  but  approach  each  other 
as  they  ascend ;  they  are  frequently  traversed  by  a  tendinous  inter- 
section. 

Relations. — By  its  external  surface  with  the  deep  cervical  fascia, 
the  platysma  myoides  and  sterno-mastoid  muscle;  by  its  internal 
surface  with  the  sterno-thyroid  and  thyro-hyoid  muscle,  the  thyroid 
gland,  and  the  superior  thyroid  artery. 

The  sterno-tliyroideus,  broader  than  the  preceding,  beneath  which 
it  lies,  arises  from  the  posterior  surface  of  the  upper  bone  of  the 
sternum,  and  from  the  cartilage  of  the  first  rib;  and  is  inserted  into 
the  oblique  line,  on  the  great  ala  of  the  thyroid  cartilage.  The  inner 
borders  of  these  muscles  lie  in  contact  along  the  middle  line,  and 
they  are  generally  marked  by  a  tendinous  intersection  at  their  lower 
part. 

Relations. — By  its  external  surface,  with  the  sterno-hyoid,  omo- 
hyoid, and  sterno-mastoid  muscle;  by  its  internal  surface,  with  the 
trachea  and  inferior  thyroid  veins,  with  the  thyroid  gland,  the  lower 
part  of  the  larynx,  the  sheath  of  the  common  carotid  artery  and 
internal  jugular  vein,  with  the  subclavian  vein  and  vena  innominnta, 
and  on  the  right  side  with  the  arteria  innominata.  The  middle  thy- 
roid vein  lies  along  its  inner  border. 

The  tliyro-hyoideus  is  the  continuation  upwards  of  the  sterno-thy- 
roid muscle.  It  arises  from  the  oblique  line  on  the  thyroid  cartilage, 


184  OMO-HYOIDEUS — ELEVATORS  OF  THE  OS  HYOIDES. 

and  is  inserted  into  the  lower  border  of  the  body  and  great  cornu  of 
the  OS  hyoides. 

Relations. — By  its  external  surface  with  the  sterno-hyoid  and 
omo-hyoid  muscle;  l?y  its  internal  surface  with  the  great  ala  of  the 
thyroid  cartilage,  the  thyro-hyoidean  membrane  and  the  superior 
laryngeal  artery  and  nerve. 

The  omo-Iiyoideus  (wM-o?,  shoulder)  is  a  double-bellied  muscle,  pass- 
ing obliquely  across  the  neck  from  the  scapula  to  the  os  hyoides;  it 
forms  an  obtuse  angle  behind  the  sterno-mastoid  muscle,  by  means 
of  a  process  of  the  deep  cervical  fascia  which  is  connected  to  the 
inner  border  of  its  tendon.  It  arises  from  the  upper  border  of  the 
scapula,  and  from  the  transverse  ligament  of  the  supra-scapular 
notch,  and  is  inserted  into  the  lower  border  of  the  body  of  the  os 
hyoides. 

Relations. — By  its  superficial  surface  with  the  trapezius,  the  sub- 
clavius  and  clavicle,  the  deep  cervical  fascia  and  platysma  myoides, 
the  sterno-mastoid,  and  the  integument.  By  its  deep  surface  with 
the  brachial  plexus,  the  scaleni  muscles,  the  phrenic  nerve,  the  sheath 
of  the  common  carotid  artery  and  jugular  vein,  the  descendens 
noni  nerve,  and  the  sterno-thyroid,  and  thyro-hyoid  muscle.  The 
scapular  portion  of  the  muscle  divides  the  great  posterior  triangle 
into  a  superior  or  occipital  triangle  ;  and  an  inferior  or  subclavian 
triangle,  which  contains  the  subclavian  artery  and  brachial  plexus 
of  nerves;  the  other  two  boundaries  of  the  latter  being  the  sterno- 
mastoid  in  front  and  the  clavicle  below.  The  hyoid  portion  of  the 
muscle  divides  the  great  anterior  triangle  into  an  inferior  carotid 
triangle,  situated  below  the  muscle,  and  into  a  superior  triangle, 
which  lies  above  the  muscle  and  is  again  subdivided  by  the  digas- 
tricus  muscle  ijito  the  submaxillary  triangle  and  the  superior  carotid 
triangle.  The  other  two  boundaries  of  the  inferior  carotid  triangle, 
are  the  middle  line  of  the  neck  in  front  and  the  anterior  border  of 
the  sterno-mastoid  behind.  The  other  boundaries  of  the  superior 
carotid  triangle,  are  the  posterior  belly  of  the  digastricus  muscle 
above  and  the  anterior  border  of  the  sterno-mastoid  behind. 

Actions. — The  four  muscles  of  this  group  are  the  depressors  of 
the  OS  hyoides  and  larynx.  The  three  former  drawing  these  parts 
downwards  in  the  middle  line,  and  the  two  omo-hyoidei  regulating 
their  traction  to  the  one  or  other  side  of  the  neck,  according  to  the 
position  of  the  head.  The  omo-hyoid  muscles,  by  means  of  their 
connexion  with  the  cervical  fascia,  are  rendered  tensors  of  that 
portion  of  the  deep  cervical  fascia  which  covers  in  the  lower  part 
of  the  neck,  between  the  two  sterno-mastoid  muscles. 

Third  Group. — Elevators  of  the  Os  Hyoides. 

Digastricus. 

Stylo-hvoid, 

Mylo-hyoid, 

Genio-hyoid, 

Genio-hyo-glossus. 


DIGASTRICUS  —  STYLO-IIYOIDEUS.  185 

Dissection. — These  are  best  dissected  by  placing  a  higli  block 
beneath  the  neck,  and  throwing  the  head  backwards.  The  integu- 
ment has  been  already  dissected  away,  and  the  removal  of  the  cel- 
lular tissue -and  fat  bring  them  clearly  into  view. 

The  digastricus  (Sis,  twice,  /arfr^,  belly)  is  a  small  muscle  situated 
immediately  beneath  the  side  of  the  body  of  the  lower  jaw;  it  is 
fleshy  at  each  extremity,  and  tendinous  in  the  middle.  It  arises 
from  the  digastric  fossa,  upon  the  inner  side  of  the  mastoid  process 
of  the  temporal  bone,  and  is  inserted  into  a  depression  on  the  inner 
side  of  the  lower  jaw  close  to  the  symphysis.  The  middle  tendon 
is  held  in  connexion  with  the  body  of  ihe  os  hyoides  by  an  aponeu- 
rotic loop,  through  which  it  plays  as  through  a  pulley ;  the  loop 
being  lubricated  by  a  synovial  membrane.  A  thin  layer  of  aponeu- 
rosis is  given  off  from" the  tendon  of  the  digastricus  at  each  side, 
which  is  connected  with  the  body  of  the  os  hyoides,  and  forms  a 
strong  plane  of  fascia  between  the  anterior  portions  of  the  two 
muscles.     This  fascia  is  named  the  supra-hijoidean. 

Relations.— By  its  swperficial  surface  with  the  platysma  myoides, 
the  sterno-mastoid,  the  anterior  fasciculus  of  the  stylo-hyoid  muscle, 
the  parotid  gland,  and  submaxillary  gland.  By  its  deej)  surface 
with  the  styloid  muscles,  the  hyo-glossus,  the  mylo-hyoid  muscle, 
the  external  carotid  artery,  the  lingual  and  the  facial  arteries,  the 
internal  carotid  artery,  the  jugular  vein,  and  the  hypo-glossal  nerve. 
The  digastric  muscle  forms  the  two  inferior  boundaries  of  the  sub- 
maxillary triangle,  the  superior  boundary  being  the  side  of  the  body 
of  the  lower  jaw.  In  the  posterior  half  of  the  submaxillary  triangle 
is  situated  the  submaxillary  gland  and  the  facial  artery. 

The  stylo-hyoideus  is  a  small  and  slender  muscle,  situated  in 
immediate  relation  with  the  posterior  belly  of  the  digastricus 
muscle,  being  pierced  by  its  tendon.  It  arises  from  the  middle  of 
the  styloid  process,  and  is  inserted  into  the  body  of  the  os  hyoides 
near  to  the  middle  line. 

Relations. — By  its  supofcial  surface  with  the  posterior  belly  of 
the  digastricus,  the  parotid  gland  and  submaxillary  gland;  its 
deep  relations  are  similar  to  those  of  the  posterior  belly  of  the 
digastricus. 

The  digastricus  and  stylo-hyoideus  must  be  removed  from  their 
connexion  with  the  lower  jaw  and  os  hyoides,  and  turned  aside  in 
order  to  see  the  next  muscle. 

The  mylo-hyoideus  ((xuXr),  mola,  i.  e.  attached  to  the  molar  ridge 
of  the  lower  jaw)  is  a  broad  triangular  plane  of  muscular  fibres, 
forming,  with  its  fellow  of  the  opposite  side,  the  inferior  wall  or 
floor  of  the  mouth.  It  arises  from  the  molar  ridge  on  the  lower 
jaw,  and  proceeds  obliquely  inwards  to  be  inserted  into  the  ropfie 
of  the  two  muscles  and  into  the  body  of  the  os  hyoides  ;  the  raph^ 
is  sometimes  deficient  at  its  anterior  part. 

Relations. — By  its  superficial  or  inferior  surface,  with  the  pla- 
tysma myoides,  the  digastricus,  the  supra-hyoidean  fascia,  the  sub- 
maxillary gland  and  the  submental  artery.     By  its  deep  or  superior 

16* 


186  MUSCLES  OF  TUE  TOiXGUE. 

surface,  with  the  genio-hyoideus,  the  gei>io-hyo-glossus,  the  hyo- 
glossus,  the  stylo-glossus,  the  gustatory  nerve,  the  hypo-glossal 
nerve,  Wharton's  duct,  the  subUngual  gland,  and  the  mucous  mem- 
brane of  the  floor  of  the  mouth. 

After  the  mylo-hyoideus  has  been  examined,  it  should  be  cut 
away  from  its  origin  and  insertion,  and  completely  removed.  The 
view  of  the  next  muscles  would  also  be  greatly  improved  by 
dividing  the  lower  jaw  a  little  to  one  side  of  the  symphysis,  and 
drawing  it  outwards,  or  by  removing  it  altogether  if  the  ramus 
have  been  already  cut  across  in  dissecting  the  internal  pterygoid 
muscle.  The  tongue  may  then  be  drawn  out  of  the  mouth  by 
means  of  a  hook. 

The  gsnio-hyoideus  {yiysiov,  the  chin)  arises  from  a  small  tubercle 
upon  the  inner  side  of  the  symphysis  of  the  lower  jaw,  and  is  inserted 
into  the  upper  part  of  the  body  of  the  os  hyoides.  It  is  a  short  and 
slender  muscle,  very  closely  connected  with  the  border  of  the  fol- 
lowing. 

Relations. — By  its  superficial  or  inferior  surface,  with  the  mylo- 
hyoideus  ;  by  the  deep  or  superior  surface  with  the  lower  border  of 
the  genio-hyo-glossus. 

The  genio-hyo-glossus  {yXCJdcfa,  the  tongue)  is  a  triangular  muscle, 
narrow  and  pointed  at  its  origin  from  the  lower  jaw,  broad  and 
fan-shaped  at  its  attachment  to  the  tongue.  It  arises  from  a 
tubercle  immediately  above  that  of  the  genio-hyoideus,  and  spreads 
out  to  be  inserted  into  the  whole  length  of  the  tongue,  from  its  base 
to  the  apex,  and  into  the  body  of  the  os  hyoides. 

Relations. — By  its  inner  surface  with  its  fellow  of  the  opposite 
side.  By  its  outer  surface  with  the  mylo-hyoideus,  the  hyo-glossus, 
the  stylo-glossus,  lingualis,  the  sublingual  gland,  the  lingual  artery 
and  the  hypo-glossal  nerve.  By  its  upper  border  with  the  mucous 
membrane  of  the  floor  of  the  mouth,  by  the  side  of  the  frsenum 
linguae  ;  and  by  the  lower  border  with  the  genio-hyoideus. 

Actions. — The  whole  of  this  group  of  muscles  acts  upon  the  os 
hyoides,  when  the  lower  jaw  is  closed,  and  upon  the  lower  jaw 
when  the  os  hyoides  is  drawn  downwards,  and  fixed  by  the  depres- 
sors of  the  OS  hyoides  and  larynx.  The  genio-hyo-glossus  is,  more- 
over, a  muscle  of  the  tongue;  its  action  upon  that  organ  shall  be 
considered  with  the  next  group. 

Fourth  Group. — Muscles  of  the  Tongue. 

Genio-hyo-glossus, 
Hyo-glossus, 
Lingualis, 
Stylo-glossus, 
.  ■  Palato-glossus. 

These  are  already  exposed  by  the  preparation  we  have  just 
made  ;  there  remains,  therefore,  only  to  dissect  and  examine  them. 


HYO-GLOSSUS LI>'GtJALIS. 


187 


The genio-hyo-glossus,  the  first  of  these  muscles,  has  been  described 
with  the  last  group. 

The  hyo-glossus  is  a  square-shaped  plane  of  nnus(jle,  arising  from 
the  whole  length  of  the  great  cornu  and  from  the  body  of  the  os 
hyoides,  and  inserted  between  the  stylo-glossus  and  lingualis  into 
the   side    of    the   tongue.      The 
direction  of  the   fibres   of    that  Fig.  82, 

portion  of  the  muscle  which 
arises  from  the  body  is  obliquely 
backwards;  and  that  from  the 
great  cornu  obliquely  forwards ; 
hence  they  are  described  by  Al- 
binus  as  two  distinct  muscles, 
under  the  names  of  the  basio- 
glossus,  and  cerato-glossus,  to 
which  he  added  a  third  fasci- 
culus, arising  from  the  lesser 
cornu,  and  spreading  along  the 
side  of  the  tongue,  the  chon- 
dro-glossus.  The  basio-glossus 
slightly  overlaps  the  cerato- 
glossus  at  its  upper  part,  and  is 
separated  from  it  by  the  trans- 
verse portion  of  the  stylo-glossus. 

Relations. — By  its  external 
surface  with  the  digastric  mus- 
cle, the  stylo-hyoideus,  stylo-glossus  and  mylo-hyoideus ;  with  the 
gustatory  nerve,  the  hypo-glossal  nerve,  Wharton's  duct  and  the 
sublingual  gland.  By  its  internal  surface  with  the  middle  con- 
strictor of  the  pharynx,  and  lingualis,  the  genio-hyo-glossus,  the 
lingual  artery,  and  the  glosso-pharyngeal  nerve. 

The  livgualis. — The  fibres  of  this  muscle  may  be  seen  tow^ards 
the  apex  of  the  tongue,  issuing  from  the  interval  between  the  hyo- 
.  glossus  and  genio-hyo-glossus  ;  it  is  best  examined  by  removing  the 
preceding  muscle.  It  consists  of  a  small  fasciculus  of  fibres, 
running  longitudinally  from  the  base,  where  it  is  attached  to  the  os 
hyoides,  to  the  apex  of  the  tongue.  It  is  in  relation  by  its  under 
surface  with  the  ranine  artery. 

Fig.  82.  The  styloid  muscles  and  the  muscles  of  the  tongue.  1.  A  portion  of  the 
temporal  bone  of  the  left  side  of  the  skull,  including  the  styloid  and  mastoid  processes, 
and  the  meatus  auditor! us  externus.  2,  2.  The  right  side  of  the  lower  jaw,  divided  at 
its  symphysis :  the  left  side  having  been  removed.  3.  The  tongue.  4.  The  genio- 
hyoideus  muscle.  5.  The  genio-hyo-glossus.  6.  The  hyo-glossus  muscle  ;  its  basio- 
glossus  portion.  7.  Its  cerato-glossus  portion.  8.  The  anterior  fibres  of  the  lingualis 
issuing  from  between  the  hyo-glossus  and  genio-hyo  glossus.  9.  The  stylo-glossus 
muscle,  with  a  small  portion  of  the  stylo-maxillary  ligament.  10.  The  stylo-hyoid. 
11.  The  stylo-pharyngeus  muscle.  12.  The  os  hyoides.  13.  The  thyro-hyoidean 
membrane.  14.  The  thyroid  cartilage.  1.5.  The  thyro  hyoideus  muscle  arising  from 
the  oblique  line  on  the  thyroid  cartilage.  16.  The  cricoid  cartilage.  17.  The  crico- 
thyroidean  membrane,  through  which  the  operation  of  laryngotomy  is  performed.  18. 
The  trachea.     19.  The  commencement  of  the  oesophagus. 


188  MUSCLES  OF  THE  PHAKYNX. 

The  stijio-glossus  arises  from  the  apex  of  the  styloid  process,  and 
from  the  stylo-maxiUary  Hgament;  and  divides  upon  the  side  of  the 
tongue  into  two4iortions,  one  transverse,  which  passes  transversely 
inwards  between  the  two  portions  of  the  hyo-glossus,  and  is. lost 
among  the  transverse  fibres  of  the  substance  of  the  tongue,  and 
another  longitudinal,  which  spreads  out  upon  the  side  of  the  tongue 
as  far  as  its  tip. 

Relations. — By  its  external  surface  with  the  internal  pterygoid 
muscle,  thegustatory  nerve,  the  parotid  gland,  sublingual  gland,  and 
the  mucous  membrane  of  the  floor  of  the  tongue.  By  its  internal 
surface  with  the  tonsil,  the  superior  constrictor  muscle  of  the 
pharynx,  and  the  hyo-glossus  muscle. 

The  palato-glossus*  passes  between  the  soft  palate,  and  the  side 
of  the  base  of  the  tongue,  forming  a  projection  of  the  mucous  mem- 
brane, which  is  called  the  anterior  pillar  of  the  soft  palate.  Its 
fibres  are  lost  superiorly  among  the  muscular  fibres  of  the  palato- 
pharyngeus,  and  inferiorly  among  the  fibres  of  the  stylo-glossus 
upon  the  side  of  the  tongue.  This  muscle  with  its  fellow  constitutes 
the  constrictor  isthmii  faucium. 

Actions. — The  genio-hyo-glossus  muscle  eflects  several  movements 
of  the  tongue,  as  might  be  expected  from  its  extent.  When  the 
tongue  is  steadied  and  pointed  by  the  other  muscles,  the  posterior 
fibres  of  the  genio-hyo-glossus  would  dart  it  from  the  mouth,  while 
its  anterior  fibres  would  restore  it  to  its  original  position.  The 
whole  length  of  the  muscle  acting  upon  the  tongue,  would  render  it 
concave  along  the  middle  line,  and  form  a  channel  for  the  current 
of  fluid  towards  the  pharynx,  as  in  sucking.  The  apex  of  the 
tongue  is  directed  to  the  roof  of  the  mouth,  and  rendered  convex 
from  before  backwards  by  the  linguales.  The  hyo-glossi,  by 
drawing  down  the  sides  of  the  tongue,  render  it  convex  along  the 
middle  line.  It  is  drawn  upwards  at  its  base  by  the  palato-glossi, 
and  backwards  or  to  either  side  by  the  stylo-glossi.  Thus  the  whole 
of  the  complicated  movements  of  the  tongue  may  be  explained,  by 
reasoning  upon  the  direction  of  the  fibres  of  the  muscles,  and  their 
probable  actions. 

Fifth  Growp. — Muscles  of  the  Pharynx. 

Constrictor  inferior, 
Constrictor  medius, 
Constrictor  superior, 
Stylo-pharyngeus, 
Palato-pharyngeus. 

Dissection. — To  dissect  the  pharynx,  the  trachea,  and  oesophagus 
are  to  be  cut  through  at  the  lower  part  of  the  neck,  and  drawn 
upwards  by  dividing  the  loose  cellular  tissue  which  connects  the 

*  Called  also  constrictor  isthmii  faucium, — G. 


CONSTRICTORS  OF  THE  PHARYNX.  Io0 

pharynx  to  the  vertebral  column.  The  saw  is  then  to  be  applied 
behind  the  styloid  processes,  and  the  base  of  the  skull  sawn  through. 
The  vessels  and  loose  structures  should  be  removed  from  the  prepa- 
ration, and  the  pharynx  stuffed  with  tow  or  wool  for  the  purpose  of 
distending  it,  and  rendering  the  muscles  more  easy  of  dissection. 
The  pharynx  is  invested  by  a  proper  pharyngeal  fascia. 

The  constructor  ivfemor,  the  thickest  of  the  three  muscles  of  this 
class,  arises  from  the  upper  rings  of  the  trachea,  from  the  cricoid 
and  the  side  of  the  thyroid  cartilage.  Its  fibres  spread  out  and  are 
inserted  into  the  fibrous  raphe  of  the  middle  of  the  pharynx,  the 
inferior  fibres  being  almost  horizontal,  and  the  superior  oblique, 
and  overlapping  the  middle  constrictor. 

Relations. — By  its  external  surface  with  the  anterior  surface  of 
the  vertebral  column,  the  longus  colli,  the  sheath  of  the  common 
carotid  artery,  the  sterno-thyroid  muscle,  the  thyroid  gland,  and 
some  lymphatic  glands.  By  its  internal  surface  with  the  middle 
constrictor,  the  stylo-pharyngeus,  the  palato-pharyngeus,  and  the 
mucous  membrane  of  the  pharynx.  By  its  lower  border,  near  to  the 
cricoid  cartilage,  it  is  in  relation  with  the  recurrent  nerve ;  and  by 
the  upper  border  with  the  superior  laryngeal  nerve. 

This  muscle  must  be  removed  before  the  next  can  be  examined. 

The  constrictor  medius  arises  from  the  great  cornu  of  the  os  hy- 
oides,  from  the  lesser  cornu,  and  from  the  stylo-hyoidean  ligament. 
It  radiates  from  its  origin  upon  the  side  of  the  pharynx,  the  lower 
fibres  descending  and  being  overlapped  by  the  constrictor  inferior, 
and  the  upper  fibres  ascending  so  as  to  cover  in  the  constrictor 
superior.  It  is  inserted  into  the  raphe  and  by  a  fibrous  aponeurosis 
into  the  basilar  process  of  the  occipital  bone. 

Relations. — By  its  external  surface  with  the  vertebral  column,  the 
longus  colli,  rectus  anticus  major,  the  carotid  vessels,  inferior  con- 
strictor, hyo-glossus  muscle,  lingual  artery,  pharyngeal  plexus  of 
nerves,  and  some  lymphatic  glands.  By  its  interned  surface,  with 
the  superior  constrictor,  stylo-pharyngeus,  palato-pharyngeus,  and 
mucous  membrane  of  the  pharynx. 

The  upper  portion  of  this  muscle  must  be  turned  down,  to  bring 
the  whole  of  the  superior  constrictor  into  view ;  in  so  doing,  the 
stylo-pharyngeus  muscle  will  be  seen  passing  beneath  its  upper 
border. 

The  constrictor  superior  is  a  thin  and  quadrilateral  plane  of  muscu- 
lar fibres,  arising  from  the  extremity  of  the  molar  ridge  of  the  lower 
jaw,  from  the  pterygo-maxillary  ligament,  and  from  the  lower  half 
of  the  internal  pterygoid  plate,  and  inserted  into  the  raphe  and 
basilar  process  of  the  occipital  bone.  Its  superior  fibres  are  arched 
and  leave  an  interval  between  its  upper  border  and  the  basilar  pro- 
cess which  is  deficient  in  muscular  fibres,  and  it  is  overlapped  in- 
feriorly  by  the  middle  constrictor.  Between  the  side  of  the  pharynx 
and  the  ramus  of  the  lower  jaw  is  a  triangular  interval,  the  w«.c///o- 
pharyngeal  space,  which  is  bounded  on  the  inner  side  by  the  supe- 


190 


STYLO-PHARYNGEUS. 


Fig. 


rior  constrictor  muscle;  on  the  outer  side  by  the  internal  pterygoid 
muscle;  and  behind  by  the  rectus  anticus  major  and  vertebral 
column.  In  this  space  are  situated  the  internal  carotid  artery,  the 
internal  jugular  vein,  and  the  glosso-pharyngeal,  pneumogastric, 
spinal  accessory,  and  hypo-glossal  nerve. 

Relations. — By  its  external  surface  with  the  vertebral  column  and 
its  muscles,  behind  ;  with  the  vessels  and  nerves  contained  in  the 
maxillo-'pharyngeal  space  laterally,  the  middle  constrictor,  stylo- 
pharyngeus,  and  tensor  palati  muscle.  By  its  internal  surface  with 
the  levator  palati,  palato-pharyngeus,  tonsil,  and  mucous  membrane 
of  the  pharynx,  the  pharyngeal  fascia  being  interposed. 

The  stylo-jiliaryngeus  is  a  long  and 
slender  muscle,  arising  from  the  inner 
side  of  the  base  of  the  styloid  process  : 
it  descends  between  the  superior  and 
middle  constrictor  muscles  and  spreads 
out  beneath  the  mucous  membrane  of 
the  pharynx,  its  inferior  fibres  being 
inserted  into  the  posterior  border  of  the 
thyroid  cartilage. 

Relations. — By  its   external  surface 
with  the  stylo-glossus  muscle,  external 
carotid  artery,  parotid  gland,  and  the 
middle    constrictor.      By  its   internal 
surface  with  the  internal  carotid  artery, 
internal  jugular  vein,  superior  constric- 
tor,   palato-pharyngeus,    and    mucous 
membrane.     Along  its  lower  border  is 
seen  the  glosso-pharyngeal  nerve  which 
crosses  it,  opposite  the  root  of  the  tongue. 
The  palato-pharyngeus  is  described  with  the  muscles  of  the  soft 
palate.     It  arises  from  the  soft  palate,  and  is  inserted  into  the  inner 
surface  of  the  pharynx,  and  posterior  border  of  the  thyroid  carti- 
lage. 

Actions. — The  three  constrictor  muscles  contract  upon  the  morsel 
of  food  as  soon  as  it  is  received  by  the  pharynx,  and  convey  it 
gradually  downwards  into  the  cesophagus.  The  stylo-pharyngei 
draw  the  pharynx  upwards  and  widen  it  laterally.  The  palato- 
pharyngei  also  draw  it  upwards,  and  narrow  the  opening  of  the 
fauces. 


Fig.  83,  A  side  view  of  Uie  muscles  of  the  pharynx.  1 .  The  trachea.  2.  The  cri- 
coid cartilage.  3.  The  crico-thyroid  membrane.  4.  The  thyroid  cartilage.  5.  The 
thyro-hyoidean  moinbrano.  fi.  The  os  hyoides.  7.  "^rhe  stylo. Iiyoidcan  ligament.  8. 
The  oesophagus,  ij.  The  inferior  constrictor.  10.  The  middle  constrictor.  11.  The 
superior  constrictor.  lU.  The  stylo-pharyngcus  muscle  passint;  down  between  the 
superior  and  middle  constrictor.  13.  Tiie  upper  concave  border  of  the  superior  con- 
strictor  ;  at  this  point  the  muscular  fibres  of  the  pliarynx  are  deficient.  14.  The 
pterygo-maxill  iry  ligament.  15.  The  buccinator  muscle,  16.  The  orbicularis  oris. 
17.  The  mylo-hyoideus. 


MUSCLES  OF  THE  SOFT  PALATE.  191 

Sixth  Group, — Muscles  of  the  soft  Palate. 

Levator  palati, 
Tensor  palati, 
Azygos  uvulge, 
Palato-glossus,  • 

Palato-pharyngeus. 

Dissection. — To  examine  these  muscles,  the  pharynx  must  be 
opened  from  behind,  and  the  mucous  membrane  carefully  removed 
from  off  the  posterior  surface  of  the  soft  palate. 

The  levator  palati,  a  moderately  thick  muscle,  arises  from  the 
extremity  of  the  petrous  bone  and  from  the  posterior  and  inferior 
aspect  of  the  Eustachian  tube,  and  passing  down  by  the  side  of  the 
posterior  nares  spreads  out  in  the  structure  of  the  soft  palate  as  far 
as  the  middle  line. 

Relations. — Externally  with  the  tensor  palati  and  superior  con- 
strictor muscle;  internally  and  posteriorly  with  the  mucous  mem- 
brane of  the  pharynx  and  soft  palate;  and  by  its  lower  border  with 
the  palato-pharyngeus. 

This  muscle  must  be  turned  down  from  its  origin  on  one  side, 
and  removed,  and  the  superior   con- 
strictor    dissected     away    from      its  Fig.  84. 
pterygoid    origin,  to   bring    the   next 
muscle  into  view. 

The  tensor  palati  (circumflexus)  is 
a  slender  and  flattened  muscle;  it 
arises  from  the  scaphoid  fossa  at  the 
base  of  the  internal  pterygoid  plate 
and  from  the  anterior  aspect  of  the 
Eustachian  tube.  It  descends  to  the 
hamular  process,  around  which  it 
turns,  and  expands  into  a  tendinous 
aponeurosis,  which  is  inserted  into 
the  transverse  ridge  on  the  horizontal 
portion  of  the  palate  bone,  and  into  the  raphe. 

Relations. — By  its  external  surface  with  the  internal  pterygoid 

Fig.  84.  Tiie  muscles  of  the  soft  palate.  1.  A  transverse  section  through  the  middle 
of  the  base  of  the  skull,  dividing  the  basilar  process  of  the  occipital  bone  in  the  middle 
line,  and  the  petrous  portion  of  the  temporal  bone  at  each  side.  2.  The  vomer  covered 
by  mucous  membrane  and  separating  the  two  posterior  nares.  3, 3.  The  Eustachian 
tubes.  4.  The  levator  palati  muscle  of  the  left  side ;  the  right  has  been  removed.  5. 
The  hamular  process  of  the  internal  pterygoid  plate  of  the  left  side,  around  which  the 
aponeurosis  of  the  tensor  palati  is  seen  turning.  6.  The  pterygo-maxillary  ligament. 
7.  The  superior  constrictor  muscle  of  the  left  side,  turned  aside.  8.  Tlie  azygos  uvulae 
muscle.  9.  The  internal  pterygoid  plate.  10.  The  external  pterygoid  plate.  11.  The 
tensor  palati  muscle.  12.  Its  aponeurosis  expanding  in  the  structure  of  the  soft 
palate.  13.  The  external  pterygoid  muscle.  14.  Tlie  attachments  of  two  pairs  of 
muscles  cut  short;  the  superior  pair  belong  to  the  gcnio-hyo-glossi  muscles  ;  tlie  infe- 
rior pair,  to  the  genio-hyoidci.  15.  The  attachment  of  tlie  mylo-hyoideus  of  one  side 
and  part  of  the  opposite.  16.  The  anterior  attachments  of  the  digastric  muscles.  17. 
The  depression  on  the  lower  jaw  corresponding  with  the  subnidxiliiwy  gland.  The 
depression  above  the  mylo-hyoideus,  on  which  the  number  15  rests,  corresponds  with 
the  sublingual  gland. 


192  PALATO-GLOSSUS PALATO-PHARYNGEUS. 

muscle;  by  its  internal  surface  with  the  levator  palati,  internal 
pterygoid  plate  and  superior  constrictor.  In  the  soft  palate,  its  ten- 
dinous expansion  is  placed  in  front  of  the  other  muscles  and  in  con- 
tact with  the  mucous  membrane. 

The  azygos  uvuIcb  is  not  a  single  muscle,  as  might  be  inferred 
from  its  name,  but  a  pair  of  small  muscles  placed  side  by  side  in 
the  middle  line  of  the  soft  palate.  They  arise  from  the  spine  of 
the  palate  bone,  and  are  inserted  into  the  uvula.  By  their  anterior 
surface  they  are  in  contact  with  the  tendinous  expansion  of  the 
levatores  palati,  and  by  the  posterior  with  the  mucous  membrane. 

The  two  next  muscles  are  brought  into  view  throughout  the  whole 
©f  their  extent,  by  raising  the  mucous  membrane  from  off  the  pillars 
of  the  soft  palate  at  each  side. 

The  palato-glossus  (constrictor  isthmii  faucium)  is  a  small  fasci- 
culus of  fibres  that  arises  in  the  soft  palate,  and  descends  to  be 
inserted  into  the  side  of  the  tongue.  It  is  the  projection  of  this 
small  muscle  covered  by  mucous  membrane,  that  forms  the  anterior 
pillar  of  the  soft  palate.  It  has  been  named  constrictor  isthmii  fau- 
cium from  a  function  it  performs  in  common  with  the  palato- 
pharyngeus,  viz.,  of  constricting  the  opening  of  the  fauces. 

The  palato-pharyngeus  forms  the  posterior  pillar  of  the  fauces  ; 
it  arises  by  an  expanded  fasciculus  from  the  lower  part  of  the  soft 
palate  where  its  fibres  are  continuous  with  those  of  the  muscle  of 
the  opposite  side ;  and  is  inserted  into  the  posterior  border  of  the 
thyroid  cartilage.  This  muscle  is  broad  above  where  it  forms  the 
whole  thickness  of  the  lower  half  of  the  soft  palate,  narrow  in  the 
posterior  pillar,  and  again  broad  and  thin  in  the  pharynx  where  it 
spreads  out  previously  to  its  insertion. 

Relations. — In  the  soft  palate  it  is  in  relation  with  the  mucous 
membrane  both  by  its  anterior  and  posterior  surface;  above,  with  the 
muscular  layer  formed  by  the  levator  palati,  and  helow  with  the 
mucous  glands  situated  along  the  margin  of  the  arch  of  the  palate. 
In  the  posterior  pillar  of  the  palate,  it  is  surrounded  for  two-thirds 
of  its  extent  by  mucous  membrane.  In  the  pharynx,  it  is  in  relation 
by  its  outer  surface  with  the  superior  and  middle  constrictor  muscles, 
and  by  its  inner  surface  with  the  mucous  membrane  of  the  pharynx, 
the  pharyngeal  fascia  being  interposed. 

Actions. — The  azygos  uvulae  shortens  the  uvula.  The  levator 
palati  raises  the  soft  palate,  while  the  tensor  spreads  it  out  laterally 
so  as  to  form  a  septum  between  the  pharynx  and  posterior  nares 
during  def];lutition.  Taking  its  fixed  point  from  below,  the  tensor 
palati  will  dilate  the  Eustachian  tube.  The  palato-glossus  and 
pharyngeus  constrict  the  opening  of  the  fauces,  and  by  drawing 
down  the  soft  palate  they  serve  to  press  the  mass  of  food  from  the 
dorsum  of  the  tongue  into  the  pharynx. 


PRjaVEHTEBRAL  MUSCLES. 


193 


Fig.  85. 


Seventh  Group. — Prcevertehral  Muscles. 
Rectus  antic  us  major, 
Rectus  anticus  minor, 
Scalenus  anticus, 
Scalenus  posticus, 
Longus  colli. 

Dissection. — These  muscles  have  already  been  exposed,  by  the 
removal  of  the  face  from  the  anterior  aspect  of  the  vertebral 
column ;  all  that  is  further  needed 
is  the  removal  of  the  fascia  by  which 
they  are  invested. 

The  rectus  anticus  major,  broad  and 
thick  above,  and  narrow  and  pointed 
below,  arises  from  the  anterior  tuber- 
cles of  the  transverse  processes  of  the 
third,  fourth,  fifth,  and  sixth  cervical 
vertebrae,  and  is  inserted  into  the 
basilar  process  of  the  occipital  bone. 

Relations. — By  its  anterior  surface 
with  the  pharynx,  the  internal  carotid 
artery,  internal  jugular  vein,  superior 
cervical  ganglion,  sympathetic  nerve, 
pneumogastric,  and  spinal  accessory 
nerve.  By  its  posterior  surface  with 
the  longus  colli,  rectus  anticus  minor, 
and  superior  cervical  vertebras. 

The   rectus    anticus    minor    arises 
from  the  anterior  border  of  the  lateral 
mass  of  the  atlas,  and  is  inserted  into 
the  basilar  process  ;  its  fibres  being  directed  obliquely  upwards  and 
inwards. 

Relations. — By  its  anterior  surface  with  the  rectus  anticus  major, 
and  externally  with  the  superior  cervical  ganglion  of  the  sympa- 
thetic. By  its  posterior  surface  with  the  articulation  of  the  condyle 
of  the  occipital  bone  with  the  atlas,  and  with  the  anterior  occipito- 
atloid  ligament. 

The  scalenus  anticus*  is  a  triangular  muscle,  as  its  name  implies, 
situated  at  the  root  of  the  neck  and  appearing  like  a  continuation  of 
the  rectus  anticus  major ;  it  arises  from  the  anterior  tubercles  of  the 
transverse  processes  of  the  third,  fourth,  fifth,  and  sixth  cervical 

Fig.  85.  The  praevertebral  group  of  muscles  of  the  neck.  1.  The  rectus  anticus 
major  muscle.  2.  The  scalenus  anticus.  3.  The  lower  part  of  the  longus  colli  of  the 
right  side ;  it  is  concealed  superiorly  by  the  rectus  anticus  major.  4.  The  rectus 
anticus  minor.  5.  The  upper  portion  of  the  longus  colli  muscle.  6.  Its  lower  portion; 
the  figure  rests  upon  the  seventh  cervical  vertebra.  7,  8.  The  scalenus  posticus.  9.  One 
of  the  intertransversales  muscles.     10.  The  rectus  lateralis  of  the  left  side. 

*  Horner  describes  three  scaleni,  viz. :  anticus,  medius,  and  posticus  ;  the  anticus 
arising  from  the  fourth,  fifth,  and  sixth;  the  rnedius  from  all  the  corneal  vertebrae; 
and  the  posticus  from  the  fifth  and  sixth.  I  have  always  had  a  difficulty  in  separating 
the  medius  and  posticus. — G. 

17 


194  LONGUS  COLLI. 

vertebrae,  and  is  inserted  into  the  tubercle  upon  the  inner  border  of 
the  first  rib. 

Relations. — By  its  anterior  surface  with  the  sterno-mastoid  and 
omo-hyoid  muscle,  with  the  cervicalis  ascendens,  and  posterior  sca- 
pular artery,  with  the  phrenic  nerve,  and  with  the  subclavian  vein, 
by  which  it  is  separated  from  the  subclavius  muscle  and  clavicle. 
By  its  -posterior  surface  with  the  nerves  which  go  to  form  the 
brachial  plexus,  and  below  with  the  subclavian  artery.  By  its 
inner  side  it  is  separated  from  the  longus  colli  by  the  vertebral  artery. 
Its  relations  with  the  subclavian  artery  and  vein  are  vefy  impor- 
tant, the  vein  being  before  and  the  artery  behind  the  muscle.* 

The  scalenus  posticus  arises  from  the  posterior  tubercles  of  all 
the  cervical  vertebrce  excepting  the  first.  It  is  inserted  by  two 
fleshy  slips  into  the  first  and  second  ribs.  The  anterior  of  the  two 
slips  is  very  large,  and  occupies  all  the  surface  of  the  rib  between 
the  groove  for  the  subclavian  artery  and  the  tuberosity.  The  pos- 
terior is  small.  Hence  the  scalenus  medius  and  posticus  of  some 
anatomists. 

Relations. — By  its  anterior  surface  with  the  brachial  plexus  and 
subclavian  artery  ;  posteriorly  with  the  levator  anguli  scapulae,  cer- 
vicalis ascendens,  transversalis  colli  and  sacro-lumbalis  ;  internally 
with  the  first  intercostal  muscle,  the  first  rib,  the  inter-transverse 
muscles,  and  cervical  vertebrae  ;  and  externally  with  the  sterno- 
mastoid,  omo-hyoid,  supra-scapular,  and  posterior  scapular  arteries. 

The  lovgus  colli  is  a  long  and  flat  muscle,  consisting  of  two 
portions.  The  upper  arises  from  the  anterior  tubercle  of  the  atlas, 
and  is  inserted  into  the  transverse  processes  of  the  third,  fourth, 
and  fifth  cervical  vertebrse.  The  lower  portion  arises  from  the 
bodies  of  the  second  and  third,  and  transverse  processes  of  the 
fourth  and  fifth,  and  passes  down  the  neck,  to  be  inserted  into  the 
bodies  of  the  three  lower  cervical  and  three  upper  dorsal  vertebrae. 
We  should  thus  arrange  these  attachments  in  a  tabular  form : 

Origin.  Insertion. 

Upper        I   1 .1  S  3^»  4th,  and  5th  transverse 

portion.      )  \      processes. 

-r  "i  2d  and  3d  bodies  I  3   lower  cervical   vertebrjB 

>  4th  and  5th  transverse  <      bodies. 
I  '      )      processes     .         •      ( 3  upper  dorsal  bodies. 

In  general  terms,  the  muscle  is  attached  to  the  bodies  and  trans- 
verse processes  of  the  five  superior  cervical  vertebrae  above,  and  to 
the  bodies  of  the  three  last  cervical  and  three  first  dorsal  below. 

Relations. — By  its  anterior  surface  with  the  pharynx,  oesophagus, 
the  sheath  of  the  common  carotid  internal  jugular  vein  and  pneumo- 
ga^ric  nerve,  the  sympathetic  nerve,  inferior  laryngeal  nerve,  and 
inferior  thyroid  artery.  By  its  posterior  surface  it  rests  upon  the 
cervical  and  upper  dorsal  vertebrae. 

*  In  a  subject  dissected  in  the  school  of  the  Middlesex  Hospital  during-  the  last 
winter,  by  Mr.  Joseph  Rogers,  the  subclavian  artery  of"  tlie  left  side  was  placed  with 
the  vein  in  front  of  the  Bcalenus  anticus  muscle. 


MUSCLES  OF  THE  TRUNK.  195 

Actions. — The  rectus  anticus  major  and  minor  preserve  the  equi- 
librium of  the  head  upon  the  atlas;  and  acting  conjointly  with  the 
longus  colli,  they  flex  and  rotate  the  head  and  the  cervical  portion 
of  the  vertebral  column.  The  scaleni  muscles,  taking  their  fixed 
point  from  below,  are  flexors  of  the  vertebral  column  ;  and  from 
above,  elevators  of  the  ribs,  and  therefore  inspiratory  muscles. 

Eighth  Group. — Muscles  of  the  Larynx. 

These  muscles  are  described  with  the  anatomy  of  the  larynx,  in 
Chapter  X. 

MUSCLES    OF    THE     TRUNK. 

The  muscles  of  the  trunk  may  be  subdivided  into  four  natural 
groups ;  viz. 

1.  Muscles  of  the  back. 

2.  Muscles  of  the  thorax. 

3.  Muscles  of  the  abdomen. 

4.  Muscles  of  the  perineum. 

1.  Muscles  of  the  hack. — The  region  of  the  back,  in  consequence  of 
its  extent,  is  common  to  the  neck,  the  upper  extremities,  and  the 
abdomen.  The  muscles  of  which  it  is  composed  are  numerous, 
and  may  be  arranged  into  six  layers. 

First  Layer.  Transversalis  colli, 

Trapezius,  Trachelo-mastoideus, 

Latissimus  dorsi.  Complexus. 

Second  Layer.  Fifth  Layer. 

Levator  anguli  scapulae,  (Dorsal  Group.) 

Rhomboideus  minor,  Semi-spinalis  dorsi, 

Rhomboideus  major.  Semi-spinalis  colli. 

Third  Layer.  (Cervical  Group.) 

Serratus  posticus  superior,  g^^J"^  P^^'!^"^  "^!^j°^'' 

Serratus  posticus  inferior,  J^^^^"^  f'^^'^'f  "^»"°^' 

Q  .     •      \^     •,•  Rectus  lateralis, 

feplenius  capitis,  ^, ,.  •  c    ■ 

o  1 ,  •      „  II-  Ubhquus  mierior, 

bpleniUS  coin.  r\\^■  • 

*^  „       ,   ^  Ubliquus  superior. 

Jtourth  Layer. 

(Dorsal  Group.)  ^'"^^^  ^«^^^' 

Sacro  lumbalis,  Multifidus  spinse, 

Longissimus  dorsi,  Levatores  costarum, 

Spinalis  dorsi.  Supra-spinales, 

(Cervical  Group.)  .  Inter-spinales, 

Cervicalis  ascendens,  Inter-transversales. 

First  Layer. 
Dissection. — The  muscles  of  this  layer  are  to  be  dissected  by 
making  an  incision  along  the  middle  line  of  the  back,  from  the 
tubercle  on  the  occipital  bone  to  the  coccyx.     From  the  upper 


196  MUSCLES  OF  THE  BACK. 

point  of  this  incision  carry  a  second  along  the  side  of  the  neck,  to 
the  middle  of  the  clavicle.  Inferiorly,  an  incision  must  be  made 
from  the  extremity  of  the  sacrum,  along  the  crest  of  the  ilium,  to 
about  its  middle.  For  convenience  of  dissection,  a  fourth  may  be 
carried. from  the  middle  of  the  spine  to  the  acromion  process.  The 
integument  and  superficial  fascia,  together,  are  to  be  dissected  off 
the  muscles,  in  the  course  of  their  fibres,  over  the  whole  of  this 
region. 

The  trapezius  muscle  (trapezium,  a  quadrangle  with  unequal 
sides)  arises  from  the  superior  curved  line  or  semicircular  ridge,  of 
the  occipital  bone,  from  the  ligamentum  nuchte,  supra-spinous 
ligament,  and  spinous  processes  of  the  last  cervical  and  all  the 
dorsal  vertebrae.  The  fibres  converge  from  these  various  points, 
and  are  inserted  into  the  scapular  third  of  the  clavicle,  the  acromion 
process,  and  the  whole  length  of  the  upper  border  of  the  spine  of  the 
scapula.  The  inferior  fibres  become  tendinous  near  to  the  scapula, 
and  glide  over  the  triangular  surface  at  the  posterior  extremity  of 
its  spine,  upon  a  bursa  mucosa.  When  the  trapezius  is  dissected 
on  both  sides,  the  two  muscles  resemble  a  trapezium,  or  diamond- 
shaped  quadrangle,  on  the  posterior  part  of  the  shoulders:  hence 
the  muscle  was  formerly  named  cucullaris  (cucullus,  a  monk's  cowl.) 
The  cervical  and  upper  part  of  the  dorsal  portion  of  the  muscle  is 
tendinous  at  its  origin,  and  forms,  with  the  muscle  of  the  opposite 
side,  a  kind  of  tendinous  ellipse. 

Relations. — By  its  superficial  surface  with  the  integument  and 
superficial  fascia,  to  which  it  is  closely  adherent  by  its  cervical  por- 
tion, loosely  by  its  dorsal  portion.  By  its  deep  surface,  from  above 
downwards,  with  the  complexus,  splenius,  levator  anguli  scapulae, 
supra-spinatus,  a  small  portion  of  the  serratus  posticus  superior, 
rhomboideus  minor,  rhomboideus  major,  intervertebral  aponeurosis 
which  separates  it  from  the  erector  spinse,  and  with  the  latissimus 
dorsi.  The  anterior  border  of  the  cervical  portion  of  this  muscle 
forms  the  posterior  boundary  of  the  posterior  triangle  of  the  neck. 
The  clavicular  insertion  of  the  muscle  sometimes  advances  to  the 
middle  of  the  clavicle,  or  as  far  as  the  outer  border  of  the  sterno- 
mastoid,  and  occasionally  it  has  been  seen  to  overlap  the  latter. 
This  is  a  point  of  much  importance  to  be  borne  in  mind  in  the 
operation  for  ligature  of  the  subclavian  artery.  The  spinal  accessory 
nerve  passes  beneath  the  anterior  border,  near  to  the  clavicle,  pre- 
viously to  its  distribution  to  the  muscle. 

The  ligamentum  nuchse  is  a  thin  cellulo-fibrous  layer  extended 
from  the  tubercle  and  spine  of  the  occipital  bone,  to  the  spinous 
process  of  the  seventh  cervical  .vertebra,  where  it  is  continuous 
with  the  supra-spinous  hgament.  It  is  connected  with  the  spinous 
processes  of  the  rest  of  the  cervical  vertebrae,  with  the  exception  of 
the  atlas,  by  means  of  a  small  fibrous  slip  which  is  sent  off  by  each. 
It  is  the  analogue  of  an  important  elastic  ligament  in  animals. 

The  latissimus  dai'si  muscle  covei's  the  whole  of  the  lower  part  of 
the  back  and  loins.     It  arises  from  the  spinous  processes  of  the 


LATISSIMUS  DORSr RHOMBOIDEUS  MINOR.  197 

six  inferior  dorsal  vertebrge,*  from  all  the  lumbar  and  sacral 
spinous  processes,  from  the  posterior  third  of  the  crest  of  the  ilium, 
and  from  the  three  lower  ribs ;  the  latter  origin  takes  place  by  mus- 
cular slips,  which  indigitate  with  the  external  oblique  muscle  of  the 
abdomen.  The  fibres  from  this  extensive  origin  converge  as  they 
ascend,  and  cross  the  inferior  angle  of  the  scapula ;  they  then  curve 
around  the  lower  border  of  the  teres  major  muscle,  and  terminate 
in  a  short  quadrilateral  tendon,f  which  lies  in  front  of  the  tendon  of 
the  teres,  and  is  inserted  into  the  bicipital  groove.  A  synovial 
bursa  is  interposed  between  the  muscle  and  the  lower  angle  of  the 
scapula,  and  another  between  its  tendon  and  that  of  the  teres  major. 
The  muscle  frequently  receives  a  small  fasciculus  from  the  scapula 
as  it  crosses  its  inferior  angle. 

Relations. — By  its  superficial  surface  with  the  integument  and 
superficial  fascia ;  the  latter  is  very  dense  and  fibrous  in  the  lumbar 
region ;  and  with  the  trapezius.  By  its  deep  surface,  from  below 
upwards,  with  the  erector  spinse,  serratus  posticus  inferior,  inter- 
costal muscles  and  ribs,  rhomboideus  major,  inferior  angle  of  the 
scapula  and  teres  major.  The  latissimus  dorsi  with  the  teres  major 
forms  the  posterior  border  of  the  axilla. 

Second  Layer. 

Dissection. — This  layer  is  brought  into  view  by  dividing  the  two 
preceding  muscles  near  to  their  insertion,  and  turning  them  to  the 
opposite  side. 

The  levator  avguli  scapulcB  arises  by  distinct  slips,  from  the  pos- 
terior tubercles  of  the  transverse  processes  of  the  four  upper  cervical 
vertebree,  and  is  inserted  into  the  upper  angle  and  posterior  border 
of  the  scapula,  as  far  as  the  triangular  smooth  surface  at  the  root  of 
its  spine. 

Relations. — By  its  superficial  surface  with  the  trapezius,  sterno- 
mastoid,  and  integument.  By  its  deep  surface  with  the  splenius 
colli,  transversalis  colli,  cervicalis  ascendens,  scalenus  posticus,  and 
serratus  posticus  superior.  The  tendons  of  origin  are  interposed 
between  the  attachments  of  the  scalenus  posticus  in  front  and  the 
splenius  colli  behind. 

The  rhomboideus  minor  (rhombus,  a  parallelogram  with  four 
equal  sides)  i§  a  narrow  slip  of  muscle,  detached  from  the  rhomboi- 
deus major  by  a  slight  cellular  interspace.  It  arises  from  the  spi- 
nous process  of  the  last  cervical  vertebra  and  ligamentum  nuchas, 
and  is  inserted  into  the  edge  of  the  triangular  surface,  on  the  pos- 
terior border  of  the  scapula. 

The  rhomboideus  major  arises  from  the  spinous  processes  of  the 
four  upper  dorsal  vertebrae  and  from  the  supra-spinous  ligament ; 
it  is  inserted  into  the  posterior  border  of  the  scapula  as  far  as  its 

*  Horner  says  seven. — G. 

+  A  small  muscular  fasciculus  from  the  pectoralis  major  is  sometimes  found  connected 
with  lliis  tendon. 

17* 


198 


MUSCLES  OF  THE  BACK. 


inferior  angle.     The  upper  and  middle  portion  of  the  insertion  is 
effected  by  means  of  a  tendinous  arch. 

Relations. — By  their  superficial  surface  the  two  rhomboid  mus- 
cles are  in  relation  with  the  trapezius,  and  the  rhomboideus  major 
with  the  latissimus  dorsi  and  integument.  By  their  dee-p  surface 
they  cover  in  the  serratus  posticus  superior,  part  of  the  erector 
spinse,  the  intercostal  muscles  and  ribs. 

Fig,  86. 


Fig.  8f5.  The  first  and  second  and  part  of  the  third  layer  of  muscles  of  the  back ;  the  first 
layer  being  shown  upon  the  right,  and  the  second  on  the  left  side.  1.  The  trapezius 
muscle.  2.  The  tendinous  portion  which,  with  a  corresponding  portion  in  the  opposite 
muscle,  forms  the  tendinous  ellipse  on  the  back  of  the  neck.  3.  The  acromion  pro- 
cess and  spine  of  the  scapula.  4.  The  latissimus  dorsi  muscle.  5.  The  deltoid.  6. 
The  muscles  of  the  dorsum  of  the  scapula,  infra-spinatus,  teres  minor,  and  teres  major. 
7.  The  external  oblique  muscle.  8.  The  gluteus  medius.  9.  The  glutei  maximi.  10. 
The  levator  anguli  scapulaj.  11.  The  rhomboideus  minor.  12.  The  rhomboideus 
major.  13.  The  splenius  capitis ;  the  muscle  immediately  above,  and  overlaid  by  the 
aplenius,  is  the  complexus.  14.  The  splenius  colli,  only  partially  seen ;  the  common 
origin  of  the  splenius  is  seen  attached  to  the  spinous  processes  below  the  lower  border 
of  the  rhomboideus  major.  15.  The  vertebral  aponeurosis.  16.  The  serratus  posticus 
inferior.  17.  The  supra-spinatus  muscle.  18.  The  infra-spinatus.  19.  The  teres 
minor  muscle.  20.  The  teres  major.  21.  The  long  head  of  the  triceps,  passing 
between  the  teres  minor  and  major  to  the  upper  arm.  22.  The  serratus  magnus,  pro- 
ceeding forwards  from  its  origin  at  the  base  of  the  scapula.  23.  The  internal  oblique 
muscle. 


RH05IB0IDEI SERRATI.  199 

Third  Layer. 

Dissection. — The  ihird  layer  consists  of  muscles  which  arise  from 
the  spinous  processes  of  the  vertebral  column,  and  pass  outwards. 
It  is  brought  into  view  by  dividing  the  levator  anguli  scapulse  near 
its  insertion,  and  reflecting  the  two  rhomboid  muscles  upwards 
froni  their  insertion  into  the  scapula.  The  latter  should  be  removed 
altogether. 

The  serratus  posticus  superior  is  situated  at  the  upper  part  of  the 
thorax;  it  arises  from  the  ligamentum  nuchse,  and  from  the  spinous 
process  of  the  last  cervical  and  two  upper  dorsal  vertebras ;  it  is 
inserted  by  four  serrations  into  the  upper  border  of  the  second, 
third,  fourth,  and  fifth  ribs. 

Relations. — By  its  superficial  surface  with  the  trapezius,  rhom- 
boideus  major  and  minor,  and  serratus  magnus.  By  its  deep  sur- 
face with  the  splenius,  the  upper  part  of  the  erector  spinee,  the 
intercostal  muscles  and  ribs. 

The  serratus  posticzis  inferior  arises  from  the  spinous  processes  of 
the  two  last  dorsal  and  two  upper  lumbar  vertebree,  and  is  inserted 
by  four  serrations  into  the  lower  border  of  the  four  lower  ribs. 

Relations. — By  its  superficial  surface  with  the  latissimus  dorsi,  its 
tendinous  origin  being  inseparably  connected  with  the  aponeurosis 
of  that  muscle.  By  its  deep  surface  with  the  aponeurosis  of  the 
obliquus  internus,  with  which  it  is  also  closely  adherent;  with  the 
erector  spinae,  the  intercostal  muscles  and  lower  ribs.  The  upper 
border  is  continuous  with  a  thin  tendinous  layer,  the  vertebral 
aponeurosis.  This  aponeurosis  consists  of  longitudinal  and  trans- 
verse fibres,  and  extends  the  whole  length  of  the  thoracic  region. 
It  is  attached  mesially  to  the  spinous  processes  of  the  dorsal  verte- 
brae, and  externally  to  the  angles  of  the  ribs ;  superiorly  it  is  con- 
tinued upwards  beneath  the  serratus  posticus  superior,  with  the 
lower  border  of  which  it  is  sometimes  connected.  It  serves  to  bind 
down  the  erector  spinse,  and  separates  it  from  the  superficial 
muscles. 

The  serratus  posticus  superior  must  be  removed  from  its  origin 
and  turned  outwards,  to  bring  into  view  the  whole  extent  of  the 
splenius  muscle. 

The  splenius  muscle  is  single  at  its  origin,  but  divides  soon  after 
into  two  portions,  which  are  destined  to  distinct  insertions.  It 
arises  from  the  lower  half  of  the  ligamentum  nuchas,  from  the 
spinous  process  of  the  last  cervical  vertebra,  and  from  the  spinous 
processes  of  the  six  upper  dorsal*  and  supra-spinous  ligament ;  it 
divides  as  it  ascends  the  neck  into  the  splenius  capitis  and  colli. 
The  splenius  capitis  is  inserted  into  the  rough  surface  of  the  occi- 
pital bone  between  the  two  semicircular  ridges,  and  into  the  mas- 
toid portion  of  the  temporal  bone. 

The  splenius  colli  is  inserted  into  the  posterior  tubercles  of  the 
transverse  processes  of  the  three  or  four  upper  cervical  vertebrae. 

*  Horner  makes  it  to  arise  but  from  four  dorsal  vertebrse. — G. 


200  MUSCLES  OF  THE  BACK. 

Relations. — By  its  superficial  surface  with  the  trapezius,  sterno- 
mastoid,  levator  anguli  scapulae,  rhomboideus  minor  and  major, 
and  serratus  posticus  superior.  By  its  deep  surface  with  the 
spinalis  dorsi,  longissimus  dorsi,  semi-spinalis  colli,  complexus, 
trachelo-mastoid,  and  transversalis  colli.  The  tendons  of  insertion 
of  the  s'plenius  colli  are  interposed  between  the  insertions  of  the 
levator  anguli  scapulae  in  front,  and  the  transversalis  colli  behind. 

The  splenii  of  opposite  sides  of  the  neck  leave  between  them  a 
triangular  interval,  in  which  the  complexus  is  seen. 

Fourth  Layer. 

Dissection. — The  two  serrati  and  two  splenii  must  be  removed 
by  cutting  them  away  from  their  origins  and  insertions,  to  bring 
the  fourth  layer  into  view. 

Three  of  these  muscles,  viz.  sacro-lumbalis,  longissimus  dorsi, 
and  spinalis  dorsi,  are  associated  under  the  name  of  erector  spinse. 
They  occupy  the  lumbar  and  dorsal  portion  of  the  back.  The 
remaining  four  are  situated  in  the  cervical  region. 

The  sacro-lumhalis  and  longissimus  dorsi  arise  by  a  common 
origin  from  the  posterior  third  of  the  crest  of  the  ilium,  from  Uie 
posterior  surface  of  the  sacrum,  and  from  the  lumbar  vertebras ; 
opposite  the  last  rib  a  line  of  separation  begins  to  be  perceptible 
between  the  two  muscles.  The  sacro-lumbalis  is  inserted  by  sepa- 
rate tendons  into  the  angles  of  the  six  lower  ribs.  On  turning  the 
muscle  a  little  outwards,  a  number  of  tendinous  slips  will  be  seen 
taking  their  origin  from  the  ribs,  and  terminating  in  a  muscular 
fasciculus,  by  which  the  sacro-lumbalis  is  prolonged  to  the  upper 
part  of  the  thorax.  This  is  the  musculus  accessorius  ad  sacro-lum- 
halem ;  it  arises  from  the  angles  of  the  six  lower  ribs,  and  is  in- 
serted by  separate  tendons  into  the  angles  of  the  six  upper  ribs. 

The  longissimus  dorsi  is  inserted  into  all  the  ribs,  between  their 
tubercles  and  angles,* 

The  spinalis  dorsi  arises  from  the  spinous  processes  of  the  two 
upper  lumbar  and  two  lower  dorsal  vertebrae,  and  is  inserted  into 
the  spinous  processes  of  all  the  upper  dorsal  vertebn'fi ;  the  two 
muscles  form  an  ellipse,  which  appears  to  enclose  the  spinous  pro- 
cesses of  all  the  dorsal  vertebras. 

Relations. — The  erector  spinae  muscle  is  in  relation  by  its  super- 
ficial surface  (in  the  lumbar  region)  with  the  conjoined  aponeurosis 
of  the  transversalis  and  internal  oblique  muscle,  which  separates  it 
from  the  aponeurosis  of  the  serratus  posticus  inferior,  and  longis- 
simus dorsi;  (in  the  dorsal  region)  with  the  vertebral  aponeurosis, 
which  separates  it  from  the  latissimus  dorsi,  trapezius,  and  serratus 
posticus  superior,  and  with  the  splenius.  By  its  deep  surface  (in  the 
lumbar  region)  with  the  multifidus  spina?,  transverse  processes  of 
the  lumbar  vertebrae,  and  with  the  middle  layer  of  the  aponeurosis 
of  the  transversalis  abdominis,  which  separates  it  from  the  quad- 
ratus  lumborum ;  (in  the  dorsal  region)  with  the  multifidus  spinee, 

*  It  is  also  inserted  into  the  ends  of  tlie  transverse  processes  of  all  the  dorsal  vcrtc- 
broe. — G. 


FOURTH  LATER. 


201 


semi-spinalis  dorsi,  levatores  costarum,  ^^S-  ^'^^ 

intercostal   muscles,  and  ribs  as  far  as 

their  angles.    Internally  or  mesially  with 

the    muhifidus  spinae,  and    semi-spinalis 

dorsi,  which  separate  it  from  the  spinous 

processes  and  arches  of  the  vertebrae. 

The  two  layers  of  aponeurosis  of  the 
transversalis  abdominis,  together  with  the 
spinal  column  in  the  lumbar  region,  and 
the  vertebral  aponeurosis  with  the  ribs 
and  spinal  column  in  the  dorsal  region, 
form' a  complete  osseo-aponeurotic  sheath 
for  the  erector  spinae. 

Cervical  Group. — The  cermcalis  as- 
cendens*  is  the  continuation  of  the  sacro- 
lumbalis  upwards  into  the  neck.  It  arises 
from  the  angles  of  the  four  upper  ribs, 
and  is  inserted  by  slender  tendons  into 
the  posterior  tubercles  of  the  transverse 
processes  of  the  four  lower  cervical  ver- 
tebrge. 

Relations. — By  its  superficial  surface 
with  the  levator  anguli  scapulae ;  by  its 
deep  surface  with  the  upper  intercostal 
muscles  and  ribs,  and  with  the  intertrans- 
verse muscles;  externally  with  the  scale- 
nus posticus ;  and  internally  with  the 
transversalis  colli.  The  tendons  of  inser- 
tion are  interposed  between  the  attach- 
ments of  the  scalenus  posticus  and  transversalis  colli. 

The  transversalis  colli  would  appear  to  be  the  continuation  up- 
wards into  the  neck  of  the  longissimus  dorsi ;  it  arises  from  the 
transverse  processes  of  the  third,  fourth,  fifth,  and  sixth  dorsal  ver- 
tebra), and  is  inserted  into  the  posterior  tubercles  of  the  transverse 
processes  of  the  four  or  five  inferior  cervical  vertebrae. 

Relations. — By  its  superficial  surface  with  the  levator  anguli  sca- 
pulas, splenius  and  longissimus  dorsi.  By  its  deep  surface  with  the 
complexus,  trachelo-mastoideus  and  vertebrae;  externally  W\\\\  the 
musculus  accessorius  ad  sacro-lumbalem,  and  cervicalis  ascendens: 
internally  with  the  trachelo-mastoideus  and  cotnplexus.  The  tendons 
of  insertion  of  this  giiuscle  are  interposed  between  the  tendons  of  in- 


Fig.  87.  The  fourth  and  fifth,  and  part  of  the  sixth  layer  of  the  muscles  of  the  back. 
1.  The  common  origin  of  the  erector  spinae  muscle.  2.  The  sacrolumbalis.  3.  The 
longissimus  dorsi.  4.  The  spinalis  dorsi.  5.  The  cervicalis  ascendens.  6.  The 
transversalis  colli.  7.  The  trachelo-mastoideus.  8.  The  complexus.  9.  The  trans- 
versalis colli,  showing  its  origin.  10.  Tlie  semispinalis  dorsi.  11.  The  semispinalis 
colli.  12.  The  rectus  posticus  minor.  13.  The  rectus  posticus  major.  14.  The  obli- 
quus  superior.  15.  The  obliquus  inferior.  16.  The  multifidus  spinoB.  17.  The  leva- 
tores  costarum.     18.  Intertransversales.     19.  The  quadratus  lumborum. 

*  Called  commonly  the  cervicalis  descendens. — G. 


202  MUSCLES  OF  THE  BACK. 

sertion  of  the  cervicalis  ascendens  on  the  outer  side,  and  of  origin  of 
the  trachelo-mastoid  on  the  inner  side. 

The  iraclieh-mastoid  is  likewise  a  continuation  upwards  from  the 
longissimus  dorsi.  It  is  a  very  slender  and  delicate  muscle,  arisivg 
from  the  transverse  processes  of  the  four  upper  dorsal,  and  four 
lower  cervical  vertebras,  and  inserted  into  the  mastoid  process  to 
the  inner  side  of  the  digastric  fossa. 

Relations. — The  same  as  those  of  the  preceding  muscle,  except- 
ing that  it  is  interposed  between  the  trans versalis  colli  and  the  com- 
plexus.  Its  tendons  of  attachment  are  the  most  posterior  of  those 
which  are  connected  with  the  posterior  tubercles  of  the  transverse 
processes  of  the  cervical  vertebrae. 

The  complexus  is  a  large  muscle,  and  with  the  splenius  forms  the 
great  bulk  of  the  back  of  the  neck.  It  crosses  the  direction  of  the 
splenius,  arising  from  the  transverse  processes  of  the  four  upper 
dorsal,*  and  from  the  transverse  and  articular  processes  of  the  four 
lower  cervical  vertebrae — and  is  inserted  into  the  rough  surface  on 
the  occipital  bone  between  the  two  curved  lines,  near  to  the  occipital 
spine.  A  portion  of  the  complexus  muscle  is  named  biventer  cervicis, 
from  consisting  of  a  central  tendon,  with  two  fleshy  bellies. 

Relations. — By  its  superficial  surface  with  the  trapezius,  splenius, 
trachelo-mastoid,  transversalis  colli,  and  longissimus  dorsi.  By  its 
deep  surface  with  the  semi-spinalis  dorsi  and  colli,  the  recti  and 
obliqui.  It  is  separated  from  its  fellow  of  the  opposite  side  by  the 
ligamentum  nuchas,  and  from  the  semi-spinalis  colli  by  the  proi'unda 
cervicis  artery,  and  princeps  cervicis  branch  of  the  occipital,  and 
by  the  posterior  cervical  plexus  of  nerves. 

Fifth  Layer. 

Dissection. — The  muscles  of  the  preceding  layer  are  to  be  re- 
moved by  dividing  them  transversely  through  the  middle,  and  turn- 
ing one  extremity  upwards,  the  other  downwards.  In  this  way  the 
whole  of  the  muscles  of  the  fourth  layer  may  be  got  rid  of,  and  the 
remaining  muscles  of  the  spine  brought  into  a  state  to  be  examined. 

The  semi-spinales  muscles  are  connected  with  the  transverse  and 
spinous  processes  of  the  vertebrae,  spanning  one-half  of  the  vertebral 
column,  hence  their  name  semi-spinales. 

The  semi-spinalis  dorsi  arises  from  the  transverse  processes  of  the 
six  lower  dorsal  vertebrae,  and  is  inserted  into  the  spinous  processes 
of  the  four  upper  dorsal,  and  two  lower  cervical  vertebrae. 

The  semi-spinalis  colli  arises  from  the  transvgrse  processes  of  the 
four  upper  dorsal  vertebrae,  and  is  inserted  into  the  spinous  processes 
of  the  four  upper  cervical  vertebrae,  commencing  with  the  axis. 

Relations. — By  their  superficial  surface  the  senii-spinales  are  in  re- 
lation from  below  upwards  with  the  spinalis  dorsi,  longissimus  dorsi, 
complexus,  splenius,  and  with  the  profunda  cervicis  and  princeps 
cervicis  artery,  and  posterior  cervical  plexus  of  nerves.  By  their 
deep  surface  with  the  multifidus  spinae  muscle. 

*  Horner  describes  its  origin  from  seven  dorsal  and  four  cervical. — G. 


SIXTH   LAYER.  203 

Occipital  Group. — This  group  of  small  muscles  is  intended  for  the 
varied  movements  of  the  cranium  on  the  atlas,  and  the  atlas  on  the 
axis.  They  are  extremely  pretty  in  appearance. 
wThe  rectus  posticus  major  arises  from  the  spinous  process  of  the 
axis,  and  is  inserted  into  the  inferior  curved  line,  on  the  occipital 
bone. 

The  rectus  posticus  minor  arises  from  the  spinous  tubercle  of  the 
atlas,  and  is  inserted  into  the  rough  surface  on  the  occipital  bone, 
beneath  the  inferior  curved  line. 

The  rectus  lateralis  is  extended  between  the  transverse  process  of 
the  atlas  and  the  occipital  bone ;  it  arises  from  the  transverse  pro- 
cess of  the  atlas,  and  is  inserted  into  the  rough  surface  of  the  occi- 
pital bone,  external  to  the  condyle. 

The  ohliqitus  inferior  arises  from  the  spinous  process  of  the  axis, 
and  passes  obliquely  outwards  to  be  inserted  into  the  extremity  of 
the  transverse  process  of  the  atlas. 

The  obliquus  superior  arises  from  the  extremity  of  the  transverse 
process  of  the  atlas,  and  passes  obliquely  inwards  to  be  inserted  into 
the  rough  surface  of  the  occipital  bone,  between  the  curved  lines. 

Relations. — By  their  superficial  surface  the  recti  and  obliqui  are 
in  relation  with  a  strong  aponeurosis  which  separates  them  from  the 
complexus.  Bj''  their  deep  surface  with  the  atlas  and  axis,  and  their 
articulations.  The  rectus  posticus  major  partly  covers  in  the  rectus 
minor. 

The  rectus  lateralis  is  in  relation  by  its  anterior  surface  with  the 
internal  jugular  vein,  and  by  its  posterior  surface  with  the  vertebral 
artery. 

Sixth  Layer. 

Dissection. — The  semi-spinales  muscles  must  both  be  removed  to 
obtain  a  good  view  of  the  multifidus  spinse  which  lies  beneath  them, 
and  fills  up  the  concavity  between  the  spinous  and  transverse  pro- 
cesses, the  whole  length  of  the  vertebral  column. 

The  multifidus  spin<B  consists  of  a  great  number  of  fleshy  fasci- 
culi, extending  between  the  transverse  and  spinous  processes  of  the 
vertebrse,  from  the  sacrum  to  the  axis.  Each  fasciculus  arises 
from  a  transverse  process,  and  is  inserted  into  the  spinous  process 
of  the  first  or  second  vertebra  above. 

Relations. — By  its  superficial  surface  with  the  longissimus  dorsi, 
semi-spinalis  dorsi,  and  semi-spinalis  colli.  By  its  deep  surface  with 
the  arches  and  spinous  processes  of  the  vertebral  column,  and  in 
the  cervical  region  with  the  ligamentum  nuchae. 

The  levatores  costarum,  twelve  in  number  on  each  side,  arise  from 
the  transverse  processes  of  the  dorsal  vertebras,  and  pass  obliquely 
outwards  and  downwards  to  be  inserted  into  the  rou^h  surface  be- 
tween  the  tubercle  and  angle  of  the  rib  below  them.  The  first  of 
these  muscles  arises  from  the  transverse  process  of  the  last  cervical 
vertebra,  and  the  last  from  that  of  the  eleventh  dorsal. 

Relatio7is. — By  their  superficial  surface  with  the  longissimus  dorsi 


204  MUSCLES  OF  THE  BACK. 

and  sacro-lumbalis.     By  their   deep   surface   with  the  intercostal 
muscles  and  ribs. 

The  supra-spinales  are  Uttle  fleshy  bands  lying  on  the  spinous 
processes  of  the  vertebras  in  the  cervical  region.  W 

The  inter-spinales  are  a  succession  of  little  pairs  of  muscles,  lying 
between  the  bifid  tubercles  of  the  spinous  processes  of  the  cervical 
vertebrae.  There  are  five  pairs  of  these  muscles ;  the  first  being 
situated  between  the  axis  and  third  vertebra,  and  the  last  between 
the  last  cervical  and  first  dorsal. 

The  inter-transversales  are  also  arranged  in  pairs,  and  pass  be- 
tween the  bifid  tubercles  of  the  transverse  processes  of  the  cervical 
vertebrae. 

The  inter-transversales,  situated  between  the  atlas  and  the  occi- 
pital bone,  are  the  recti  laterales.  They  are  sometimes  found  in 
the  lumbar  regions. 

Relations. — In  front  with  the  rectus  anticus  major  and  longus 
colli ;  and  behind  by  the  muscles  of  the  back  of  the  neck.  They 
are  separated  from  each  other  by  the  anterior  branch  of  the  cer- 
vical nerves,  and  by  the  vertebral  artery  and  veins. 

With  regard  to  the  origin  and  insertion  of  the  muscles  of  the 
back,  the  student  should  be  informed  that  no  regularity  attends  their 
attachments.  At  the  best,  a  knowledge  of  their  exact  connexions, 
even  were  it  possible  to  retain  it,  would  be  but  a  barren  information, 
if  not  absolutely  injurious,  as  tending  to  exclude  more  valuable 
learning.  I  have  therefore  endeavoured  to  arrange  a  plan,  by 
which  they  may  be  more  easily  recollected,  by  placing  them  in  a 
tabular  form,  that  the  student  may  see  at  a  single  glance,  the  origin 
and  insertion  of  each,  and  compare  the  natural  grouping  and  simi- 
larity of  attachments  of  the  various  layers.  In  this  manner  also 
their  actions  will  be  better  comprehended,  and  learnt  with  greater 
facility. 

Actions. — The  upper  fibres  of  the  trapezius  draw  the  shoulder  up- 
wards and  backwards;  the  middle  fibres,  directly  backwards;  and 
the  lower,  downwards  and  backwards.  The  lower  fibres  also  act 
by  producing  rotation  of  the  scapula  upon  the  chest.  If  the  shoulder 
be  fixed  the  upper  fibres  will  flex  the  spine  towards  the  correspond- 
ing side.  The  latissimus  dorsi  is  a  muscle  of  the  arm,  drawing  it 
backwards  and  downwards,  and  at  the  same  time  rotating  it  in- 
wards ;  if  the  arm  be  fixed,  the  latissimus  dorsi  will  draw  the  spine 
to  that  side,  and  raising  the  lower  ribs  be  an  inspiratory  muscle  ; 
and  if  both  arms  be  fixed,  the  two  muscles  will  draw  the  whole 
trunk  forvvards,  as  in  climbing  or  walking  on  crutches.  The  levator 
anguli  scapula;  lifts  the  upper  angle  of  the  scapula,  and  with  it  the 
entire  shoulder,  and  the  rhomboidei  carry  the  scapula  and  shoulder 
upwards  and  backwards. 

The  serrati  are  respiratory  muscles  acting  in  opposition  to  each 
other — the  serratus  posticus  superior  drawing  the  ribs  upwards,  and 
thereby  expanding  the  chest;  and  the  inferior,  drawing  the  lower 
ribs  downwards   and   diminishing  the  cavity  of  the  chest.     The 


SIXTH  LAYER.  205 

former  is  an  inspiratory,  the  latter  an  expiratory  muscle.  The 
splenii  muscles  of  one  side  draw  the  vertebral  column  backwards 
and  to  one  side,  and  rotate  the  head  towards  the  corresponding 
shoulder.  The  muscles  of  opposite  sides  acting  together,  will  draw 
the  head  directly  backwards.  They  are  the  natural  antagonists  of 
the  sterno-mastoid  muscles. 

The  sacro-himhalis  with  its  accessory  muscle,  the  longissimus  dorsi 
and  spinalis  dorsi,  are  known  by  ihe  general  term  of  erector  spincE, 
which  sufficiently  expresses  their  actions.  They  keep  the  spine 
supported  in  the  vertical  position  by  their  broad  origin  from  below, 
and  by  means  of  their  insertion  by  distinct  tendons  into  the  ribs  and 
spinous  processes.  Being  made  up  of  a  number  of  distinct  fasciculi, 
which  alternate  in  their  actions,  the  spine  is  kept  erect  without 
fatigue,  even  when  they  have  to  counterbalance  a  corpulent  abdo- 
minal developement.  The  continuations  upwards  of  these  muscles 
into  the  neck  preserve  the  steadiness  and  uprightness  of  that  region. 
When  the  muscles  of  one  side  act  alone,  the  neck  is  rotated  upon 
its  axis.  The  complexus,  by  being  attached  to  the  occipital  bone, 
draws  the  head  backwards,  and  counteracts  the  muscles  on  the 
anterior  part  of  the  neck.    It  assists  also  in  the  rotation  of  the  head. 

The  semi-spinales  and  muUifidus  spincB  muscles  act  directly  on 
the  vertebrjE,  and  contribute  to  the  general  action  of  supporting  the 
vertebral  column  erect. 

The  four  little  muscles  situated  between  the  occiput  and  the  two 
first  vertebrse,  effect  the  various  movements  between  these  bones  ; 
the  recti  producing  the  antero-posterior  actions,  and  the  ohliqui  the 
rotary  motions  of  the  atlas  on  the  axis. 

The  actions  of  the  remaining  muscles  of  the  spine,  the  supra  and 
inter-spinales  and  inter -transver sales,  are  expressed  in  their  names. 
They  approximate  their  attachments  and  assist  the  more  powerful 
muscles  in  preserving  the  erect  position  of  the  body. 

The  levatores  cosiarum  raise  the  posterior  parts  of  the  ribs,  and 
are  probably  more  serviceable  in  preserving  the  articulation  of  the 
ribs  from  dislocation,  than  in  raising  them  in  inspiration. 

In  examining  the  following  table,  the  student  will  observe  the 
constant  recurrence  of  the  number ^wr  in  the  origin  and  insertion 
of  the  muscles.  Sometimes  the  four  occurs  at  the  top  or  bottom  of 
a  region  of  the  spine,  and  frequently  includes  a  part  of  two  regions, 
and  takes  two  from  each,  as  in  the  case  of  the  serrati.  Again,  he 
will  perceive  that  the  muscles  of  the  upper  half  of  the  table  take 
their  origin  from  spinous  processes,  and  pass  outwards  to  transverse, 
whereas  the  lower  half  arise  mostly  from  transverse  processes.  To 
the  student,  then,  we  commit  these  reflections,  and  leave  it  to  the 
peculiar  tenor  of  his  own  mind  to  make  such  arrangements  as  will 
be  best  retained  by  his  memory. 


18 


206 


TABLE  OF  THE  ORIGIN  AND  INSERTION 


ORIGIN. 


Layers. 


Isl  Layer. 

Trapezius     .    .  < 

Latissimus  dorsi  < 

2d  Layer. 

Levator  anguli  ? 

scapulae     .     .  S 

Rhomboideus  ) 

iniu  S 
Rhomboideua  — ajor 

3d  Layer. 

Serratus  posticus  ( 

superior      .    .  i 

Serratus  posticus  ) 

inferior     .    .  ) 

Splenius  capitis  ( 

Splenius  colli    .  j 

ith  Layer. 


Spinous  Processes. 


last  cervical, 
12  dorsal  .     . 

6  lower  dorsal, 
5  lumbar .    . 


lig.  nuchffi, 

last  cervical 
4  upper  dorsal . 


Transverse 
Processes. 


lig.  nuchse, 
last  cervical, 
2  upper  dorsal 

2  lower  dorsal, 
2  upper  lumbar 

lig.  nuchse, 
last  cervical, 
6  upper  dorsal 


4  upper  cervical 


3  lower 


Additional. 


occipital  bone,  and  ] 
ligameniumnuchae ' 

sacrum  and  ilium 


Sacro-lumbalis . 

accessoriusad  > 

sacro-lumbalem  S 

Longissimus  dursi 
Spinalis  dorsi    . 
Cervicalis  ascendens 

Transversalis  colli 

Trachelo-mas-        ) 
toideus .    .    .      ^ 

Complexus  .    .    . 

5th  Layer. 
Semi-spinalis  dorsi 

Semi-spinalis  colli 

Rectus  posticus  maj 
Rectus  posticus  min. 
Rectus  lateralis 
Obliquus  inferior 
Obliquus  superior 


6th  Layer. 
Miiltifidus  spiniB 


2  lower  dorsal, 
2  upper  lumbar 


angles  of 
6  lower 


axis 
atlas 


Levatores  cosfarum 

Supra-spinales  .  . 
Inter-spinales  .  . 
Inter-transversales 


cervical   . 
cervical  . 


3d,  4th,  5th, 

and  6th  dorsal 
4  upper  dorsal, 

41owercervical 
4  upper  dorsal, 

4  lower  cervical 


6  lower  dorsal  , 
4  upper  dorsal 


angles  of 
4  upper 


atlas 
axis 


from  sacrum  to 
3d  cervical   . 

last  cervical  and 
eleven  dorsal 


cervical 


sacrum  and  ilium 


sacrum  and  lumbar  ] 
vertebrtB  .    .     " 


OF  THE  MUSCLES  OF  THE  BACK. 


207 


INSERTION. 


Spinous  Processes. 


8  upper  dorsal. 


4  upper  dorsal, 
2  lower  cervical. 

4  upper  cervical, 
except  atlas. 


from  last  lumbar  to 
axis. 


cervical, 
cervical. 


Transverse 
Processes. 


4  upper  cervical. 


4  lower  cervical. 
4  lower  cervical. 


atlas. 


cervical. 


Ribs. 


2d,  3d.  4th,  and  5lh. 
4  lower  ribs. 


angles  of  6  lower. 

angles  of  6  upper. 

all  the  ribs  between  the 
tubercles  and  angles. 


all  the  ribs  between  the 
tubercles  and  angles. 


Additional. 


clavicle  and  spine  of 

the  scapula, 
posterior  bicipital  ridge 

of  the  humerus. 


angle  and  base  of  the 
scapula. 

base  of  the  scapula. 

base  of  the  scapula. 


occipital  and  mastoid 
portion  of  temporal 
bone. 


mastoid  process. 

occipital  bone  between 
the  curved  lines. 


occipital  bone, 
occipital  bone, 
occipital  bone. 

occipital  bone. 


208  MUSCLES  OP  THE  THORAX. 


Muscles  of  the  Thorax. 

_  The  principal  muscles  situated  upon  the  thorax  belong  in  their 
actions,  to  the  upper  extremity,  with  which  they  will  be  described. 
They  are  the  pectoralis  major  and  minor,  subclavius  and  serratus 
magnus.  The  true  thoracic  muscles  are  few  in  number,  and  apper- 
tain exclusively  to  the  actions  of  the  ribs  ;  they  are,  the — 

Intercostales  externi, 
Intercostales  interni, 
Triangularis  sterni. 

The  intercostal  muscles  are  two  planes  of  muscular  and  tendinous 
fibres  directed  obhquely  between  the  adjacent  ribs  and  closing  the 
intercostal  spaces.  They  are  seen  partially  upon  the  removal  of 
the  pectoral  muscles,  or  upon  the  inner  surface  of  the  chest.  The 
triangularis  sterni  is  within  the  chest,  and  requires  the  removal  of  the 
anterior  part  of  the  thorax  to  bring  it  into  view. 

The  intercostales  externi,  eleven  on  each  side,  commence  pos- 
teriorly at  the  vertebral  column,  and  advance  forwards  to  the  costal 
cartilages,  where  they  terminate  in  a  thin  aponeurosis  which  is  con- 
tinued onwards  to  the  sternum.-  Their  fibres  are  directed  obliquely 
downwards  and  inwards,  pursuing  the  same  line  with  those  of  the 
external  oblique  muscle  of  the  abdomen.  They  are  thicker  than 
the  internal  intercostals. 

The  intercostales  interni,  also  eleven  on  each  side,  commence 
anteriorly  at  the  sternum,  and  extend  backwards  as  far  as  the  angles 
of  the  ribs,  whence  they  are  prolonged  to  the  vertebral  column  by  a 
thin  aponeurosis.  Their  fibres  are  directed  obliquely  downwards 
and  backwards,  and  correspond  in  direction  with  those  of  the  inter- 
nal oblique  muscle  of  the  abdomen.  The  two  muscles  cross  each 
other  in  the  direction  of  their  fibres. 

In  structure  the  intercostal  muscles  consist  of  an  admixture  of 
muscular  and  tendinous  fibres.  They  arise  from  the  two  lips  of  the 
lower  border  of  the  ribs,  the  external  from  the  outer  lip,  the  internal 
from  the  inner,  and  are  inserted  into  the  upper  border. 

Relations. — The  external  intercostals,  by  their  external  surface 
with  the  muscles  which  immediately  invest  the  chest,  viz.,  with  the 
pectoralis  major  and  minor,  the  serratus  magnus,  serratus  posticus 
superior  and  inferior,  scalenus  posticus ;  sacro-lumbalis,  and  lon- 
gissimus  dorsi,  with  their  continuations,  the  cervicalis  ascendens  and 
transversalis  colli ;  thelevatores  costarum,  and  the  obliquus  externus 
abdominis.  By  their  internal  surface  with  the  internal  intercostals, 
the  intercostal  vessels  and  nerves,  and  a  thin  aponeurosis,  and  pos- 
teriorly with  the  pleura.  The  internal  intercostals,  by  their  external 
surface  with  the  external  intercostals,  and  intercostal  vessels  and 
nerves  ;  by  their  internal  surface  with  the  pleura  coslalis,  the  trian- 
gularis sterni  and  diaphragm. 

Connected  with  the  internal  intercostals  are  a  variable  number  of 


MUSCLES  OF  THE  THORAX. 


209 


muscular  fasciculi  which  pass  from  the  inner  surface  of  one  rib  near 
its  middle  to  the  next  or  next  but  one  below ;  these  are  the  subcostal 
or  more  correctly  the  intracostal  muscles. 


Fig-. 


Fig.  88.  The  muscles  of  the  anterior  aspect  of  the  trunk;  on  the  left  side  the  super- 
ficial layer  is  seen,  and  on  the  right  the  deeper  layer.  1.  The  pectoralis  major  muscle. 
2.  The  deltoid;  the  interval  between  these  muscles  lodges  the  cephalic  vein.  3.  The 
anterior  border  of  the  latissimus  dorsi.  4.  The  serrations  of  the  serratus  magnus. 
5.  The  subclavius  muscle  of  the  right  side.  6.  The  pectoralis  minor.  7.  The  coraco- 
brachialis  muscle.  8.  The  upper  part  of  the  biceps  muscle,  showing  its  two  heads. 
9.  The  coracoid  process  of  the  scapula.  10.  The  serratus  magnus  of  the  right  side. 
11.  The  external  intercostal  muscle  .of  the  fifth  intercostal  space.  12.  The  external 
oblique  muscle.  13.  Its  aponeurosis;  the  median  line  to  the  right  of  this  number  is 
the  linea  alba;  the  flexuous  line  to  its  left  is  the  linca  semilunaris  ;  and  the  transverse 
lines  above  and  below  liie  number,  the  linete  transverste,  of  which  there  were  only 
three  in  this  subject.  14.  Poupart's  ligament.  15.  The  external  abdominal  ring;  the 
margin  above  the  ring  is  tlie  superior  or  internal  pillar ;  the  margin  below  the  ring, 
the  inferior  or  external  pillar ;  the  curved  interculumnar  fibres  are  seen  proceeding  up- 
wards  from  Poupart's  ligament  to  strengthen  the  ring.  The  numbers  14  and  15  are 
situated  upon  the  fascia  lata  of  the  thigh  ;  the  opening  immediately  to  the  right  of  15 
is  the  siiphenous  opening.  16.  The  rectus  muscle  of  the  right  side  brought  into  view 
by  the  removal  of  the  anterior  seg-ment  of  its  sheath  :  *  the  posterior  segment  of  its 
sheath  with  the  divided  edge  of  the  anterior  segment.  17.  The  pyramidalis  muscle. 
18.  The  internal  oblique  muscle.  10.  The  conjoined  tendon  of  the  iniornal  obli!]ue 
and  transversalis  descending  behind  Poupart's  ligament  to  the  pectinc.il  line.  20.  Tlie 
arch  formed  between  the  lower  curved  border  of  the  internal  oblique  muscle  and  Pou- 
part's ligament;  it  is  beneath  this  arch  thai  the  spermatic  cord  and  hernia  pass. 

18* 


210  MUSCLES  OF  THE  ABDOMEN. 

The  triangularis  sferni,  situated  upon  the  inner  wall  of  the  front  of 
the  chest,  arises  by  a  thin  aponeurosis  from  the  side  of  the  sternum, 
ensiform  cartilage,  and  sternal  extremities  of  the  costal  cartilages  ; 
and  is  inserted  by  fleshy  digitations  into  the  cartilages  of  the  third, 
fourth,  fifth  and  sixth  ribs,  and  often  into  that  of  the  second. 

Relations. — By  its  external  surface  with  the  sternum,  the  ensiform 
cartilage,  the  costal  cartilages,  internal  intercostal  muscles,  and  in- 
ternal mammary  vessels.  By  its  internal  surface  with  the  pleura 
costalis,  the  cellular  tissue  of  the  anterior  mediastinum  and  the  dia- 
phragm. 

Actions. — The  intercostal  muscles  raise  the  ribs  when  they  act 
from  above,  and  depress  them  when  they  take  their  fixed  point  from 
below.  They  are,  therefore,  both  inspiratory  and  expiratory  muscles. 
The  triangularis  sterni  draws  down  the  costal  cartilages,  and  is 
therefore  an  expiratory  muscle. 

Muscles  of  the  Abdomen. 

The  muscles  of  this  region  are  the — 

Obliquus  externus  (descendens), 
'^  Obliquus  internus  (ascendens), 

Cremaster, 
Transversalis, 
Rectus, 
Pyramidalis, 
Quadratus  lumborum, 
Psoas  parvus, 
Diaphragm. 

Dissection. — The  dissection  of  the  abdominal  muscles  is  to  be 
commenced  by  making  three  incisions : — the  first,  vertical,  in  the 
middle  line,  from  over  the  lower  part  of  the  sternum  to  the  pubes; 
the  second,  oblique,  from  the  umbilicus,  upwards  and  outwards,  to 
the  outer  side  of  the  chest,  as  high  as  the  fifth  or  sixth  rib ;  and  the 
third,  oblique,  from  the  umbilicus,  downwards  and  outwards,  to  the 
middle  of  the  crest  of  the  ilium.  The  three  flaps  included  by  these 
incisions  should  then  be  dissected  back  in  the  direction  of  the  fibres 
of  the  external  oblique  muscle,  beginning  at  the  angle  of  each.  The 
integument  and  superficial  fascia  should  be  dissected  off  together  so 
as  to  expose  the  fibres  of  the  muscle  at  once. 

If  the  external  oblique  muscle  be  dissected  on  both  sides,  a  white 
tendinous  line  will  be  seen  along  the  middle  of  the  abdomen,  extend- 
ing from  the  ensiform  cartilage  to  the  os  pubis ;  this  is  the  linea  alba. 
A  little  external  to  it,  on  each  side,  two  curved  lines  will  be  observed 
extending  from  the  sides  of  the  chest  to  the  os  pubis,  and  bounding 
the  recti  muscles :  these  are  the  linece  semilunares.  Some  transverse 
lines,  Unece  transversa;,  three  or  four  in  number,  connect  the  lineae 
semilunares  with  the  linca  alba. 

The  external  oblique  muscle  {obliquus  externus  abdominis,  descen- 


MUSCLES  OF  THE  ABDOMEN.  211 

dens)  is  the  external  flat  muscle  of  the  abdomen.  Its  name  is  derived 
from  the  obliquity  of  its  direction,  and  the  descending  course  of  its 
fibres.  It  arises  by  fleshy  digitations  from  the  external  surface  of 
the  eight  inferior  ribs.  The  five  upper  digitations  being  received 
between  corresponding  processes  of  the  serratus  magnus,  and  the 
three  lower  of  the  latissimus  dorsi ;  it  spreads  out  into  a  broad 
aponeurosis,  which  is  inserted  into  the  outer  lip  of  the  crest  of  the 
ilium  for  one  half  its  length,  the  anterior  superior  spinous  process  of 
the  ilium,  spine  of  the  os  pubis,  pectineal  line,  front  of  the  os  pubis, 
and  linea  alba. 

The  lower  border  of  the  aponeurosis,  which  is  stretched  between 
the  anterior  superior  spinous  process  of  the  ilium  and  the  spine  of 
the  OS  pubis,  is  folded  inwards,  forming  Poupart's  ligament;  the  in- 
sertion into  the  pectineal  line  is  Gimbernafs  ligament. 

Just  above  the  crest  of  the  os  pubis  is  the  external  abdominal  ring, 
a  triangular  opening  formed  by  the  separation  of  the  fibres  of  the 
aponeurosis  of  the  external  oblique.  It  is  oblique  in  its  direction, 
and  corresponds  with  the  course  of  the  fibres  of  the  aponeurosis.  It 
is  bounded  below  by  the  crest  of  the  os  pubis;  on  either  side,  by  the 
borders  of  the  aponeurosis,  which  are  called  jyillars ;  and  above  by 
some  curved  fibres  (inter-columnar),  which  originate  from  Poupart's 
ligament,  and  cross  the  upper  angle  of  the  ring,  so  as  to  give  it 
strength.  The  external  pillar,  which  is  at  the  same  time  inferior, 
from  the  obliquity  of  the  opening  is  inserted  into  the  spine  of  the 
os  pubis ;  the  internal  or  superior  pillar  forms  an  interlacement  with 
its  fellow  of  the  opposite  side  over  the  front  of  the  symphysis  pubis. 
The  external  abdominal  ring  gives  passage  to  the  spermatic  cord 
in  the  male,  and  round  ligament  in  the  female ;  they  are  both  in- 
vested in  their  passage  through  it  by  a  thin  fascia  derived  from  the 
edges  of  the  ring,  and  called  inter-columnar  fascia,  or  fascia  sper- 
matica. 

The  pouch  of  inguinal  hernia,  in  passing  through  this  opening, 
receives  the  inter-columnar  fascia,  as  one  of  its  coverings. 

Relations. — By  its  external  surface  with  the  superficial  fascia  and 
integument,  and  with  the  cutaneous  vessels  and  nerves,  particularly 
the  superficial  epigastric  and  superficial  circumflex  ilii  vessels.  It 
is  generally  overlapped  posteriorly  by  the  latissimus  dorsi.  By  its 
internal  surface  with  the  internal  oblique,  the  lower  part  of  the  eight 
inferior  ribs  and  intercostal  muscles,  the  cremaster,  the  spermatic 
cord  in  the  male,  and  the  round  ligament  in  the  female. 

The  external  oblique  is  now  to  be  removed  by  making  an  incision 
across  the  ribs,  just  below  its  origin,  to  its  posterior  border;  and 
another  along  Poupart's  ligament  and  the  crest  of  the  ilium.  Pou- 
part's ligament  should  be  left  entire,  as  it  gives  attachment  to  the 
next  muscles.  The  muscle  may  then  be  turned  forwards  towards 
the  linea  alba,  or  removed  altogether. 

The  internal  oblique  muscle  {obliquus  internus  abdominis,  ascen- 
dens)  is  the  middle  flat  muscle  of  the  abdomen.  It  arises  from  the 
outer  half  of  Poupart's  ligament,  from  the  middle  of  the  crest  of  the 


212  MUSCLES  OF  THE  ABDOMEN. 

ilium  for  two-thirds  of  its  length,  and  by  a  thin  aponeurosis  from 
the  spinous  processes  of  the  lumbar  vertebrae.*  Its  fibres  diverge 
from  their  origin,  so  that  those  from  Poupart's  ligament  curve 
downwards,  those  from  the  anterior  part  of  the  crest  of  the  ilium 
pass  transversely,  and  the  rest  ascend  obliquely.  The  muscle  is 
insertp-d  into  the  pectineal  line,  crest  of  the  os  pubis,  linea  alba,  and 
lower  borders  of  the  five  inferior  ribs. 

Along  the  upper  three-fourths  of  the  linea  semilunaris,  the  aponeu- 
rosis of  the  internal  oblique  separates  into  two  lamellae,  which  pass 
one  in  front  and  the  other  behind  the  rectus  muscle  to  the  linea  alba, 
where  they  are  inserted  ;  along  the  lower  fourth,  the  aponeurosis 
passes  altogether  in  front  of  the  rectus  without  separation.  The 
two  layers  which  thus  enclose  the  rectus,  form  for  it  a  partial 
sheath. 

The  lowest  fibres  of  the  internal  oblique  are  inserted  into  the 
pectineal  line  in  common  with  those  of  the  transversalis  muscle. 
Hence  the  tendon  of  this  insertion  is  called  the  conjoined  tendon  of 
the  internal  oblique  and  transversalis.  This  structure  corresponds 
wuth  the  external  abdominal  ring,  and  forms  a  protection  to  what 
would  otherwise  be  a  weak  point  in  the  abdomen.  Sometimes  it  is 
insufficient  to  resist  the  pressure  from  within,  and  becomes  forced 
through  the  external  ring:  it  then  forms  the  distinctive  covering  of 
direct  inguinal  hernia. 

The  spermatic  cord  passes  beneath  the  arched  border  of  the  in- 
ternal oblique  muscle,  between  it  and  Poupari's  ligament.  During 
its  passage  some  fibres  are  given  off  from  the  lower  border  of  the 
muscle,  which  accompany  the  cord  downwards  to  the  testicle,  and 
form  loops  around  it :  this  is  the  cremaster  muscle.  In  the  descent 
of  oblique  inguinal  hernia,  which  travels  the  same  course  with  the 
spermatic  cord,  the  cremaster  muscle  forms  one  of  its  coverings. 

The  cremaster,  considered  as  a  distinct  muscle,  arises  from  the 
middle  of  Poupart's  ligament,  and  forms  a  series  of  loops  upon  the 
spermatic  cord.  A  few  of  its  fibres  are  inserted  into  the  tunica 
vaginalis,  the  rest  ascend  along  the  inner  side  of  the  cord,  to  be 
inserted,  with  the  conjoined  tendon,  into  the  pectineal  line  of  the  os 
pubis. 

Relations. — The  internal  oblique  is  in  relation  by  its  external  sur- 
face with  the  external  oblique,  latissimus  dorsi,  spermatic  cord  and 
external  abdominal  ring.  By  its  internal  surface  with  the  trans- 
versalis muscle,  the  fascia  transversalis,  the  internal  abdominal 
ring,  and  spermatic  cord.  By  its  lower  and  arched  border  with  the 
spermatic  cord,  forming  the  upper  boundary  of  the  spermatic  canal. 

The  cremaster  is  in  relation  by  its  external  surface  with  the 
aponeurosis  of  the  external  oblique  and  inter-columnar  fascia;  and 
by  its  internal  surface  with  the  fascia  propria  of  the  spermatic 
cord. 

The  internal  oblique  muscle  is  to  be  removed  by  separating  it 

*  From  the  three  inferior  lumbar  spinous  processes  and  all  those  of  the  sacrum. — G. 


MUSCLES  OF  THE  ABDOMEN.  213 

from  its  attachment  to  the  ribs  above,  and  to  the  crest  of  the  ilium 
and  Poupart's  ligament  below.  It  should  be  divided  behind  by  a 
vertical  incision  extending  from  the  last  rib  to  the  crest  of  the  ilium, 
as  its  lumbar  attachment  cannot  at  present  be  examined.  Tiie 
muscle  is  then  to  be  turned  forwards.  Some  degree  of  care  will 
be  required  in  performing  this  dissection,  from  the  difficulty  of  dis- 
tinguishing between  this  muscle  and  the  one  beneath.  A  thin  layer 
of  cellular  tissue  is  all  that  separates  them  for  the  greater  part  of 
their  extent.  Near  the  crest  of  the  ilium  the  ^circumflex  ilii  artery 
ascends  between  the  two  muscles,  and  forms  a  valuable  guide  to 
their  separation.  Just  above  Poupart's  ligament  they  are  so  closely 
connected  that  it  is  impossible  to  divide  them. 

The  transversalis  is  the  internal  flat  muscle  of  the  abdomen  ;  it  is 
transverse  in  the  direction  of  its  fibres,  as  is  implied  in  its  name.  It 
arises  from  the  outer  third  of  Poupart's  ligament,  from  the  internal 
lip  of  the  crest  of  the  ilium,  its  anterior  two  thirds  ;  from  the  spinous 
and  transverse  processes  of  the  lumbar  vertebrae,*  and  from  the  inner 
surfaces  of  the  six  inferior  ribs,  indigitating  with  the  diaphragm. 
Its  lower  fibres  curve,  downwards,  to  be  inserted,  with  the  lower 
fibres  of  the  internal  oblique,  into  the  pectineal  line,  and  form  the 
conjoined  tendon.  Throughout  the  rest  of  its  extent  it  is  inserted 
into  the  crest  of  the  os  pubis  and  linea  alba.  The  lower  fourth  of 
its  aponeurosis  passes  in  front  of  the  rectus  to  the  linea  alba  ;  the 
upper  three-fourths  with  the  posterior  lamella  of  the  internal  oblique, 
behind  it. 

The  fosterior  aponeurosis  of  the  transversalis  divides  into  three 
lamellae  ; — anterior,  which  is  attached  to  the  bases  of  the  transverse 
processes  of  the  lumbar  vertebrae  ;  middle,  to  the  apices  of  the  trans- 
verse processes ;  and  posterior,  to  the  apices  of  the  spinous  processes. 
The  anterior  and  middle  lamellae  enclose  the  quadratus  lumborum 
muscle ;  and  the  middle  and  posterior,  the  erector  spinse.  The  union 
of  the  posterior  lamella  of  the  transversalis  with  the  posterior  aponeu- 
rosis of  the  internal  oblique,  serratus  posticus  inferior,  and  latissimus 
dorsi,  constitutes  the  lumbar  fascia. 

Relations. — By  its  external  surface  with  the  internal  oblique,  the 
internal  surfaces  of  the  lower  ribs,  and  internal  intercostal  muscles. 
By  its  internal  surface  with  the  transversalis  fascia,  which  separates 
it  from  the  peritoneum,  with  the  psoas  magnus,  and  with  the  lower 
part  of  the  rectus  and  pyramidalis.  The  spermatic  cord  and  oblique 
inguinal  hernia  pass  beneath  the  lower  border,  but  have  no  direct  re- 
lation with  it. 

To  dissect  the  rectus  muscle,  the  sheath  should  be  opened  by  a 
vertical  incision  extending  from  over  the  cartilages  of  the  lower 
ribs  to  the  front  of  the  os  pubis.  The  sheath  may  then  be  dissected 
off  and  turned  to  either  side :  this  is  easily  done  excepting  at  the 
lineae  trans  versae,  where  a  close  adhesion  subsists  between  the  muscle 

*  From  the  transverse  processes  of  the  last  dorsal  and  four  superior  lumbar  verte- 
brae.—G. 


214 


TRANSVERSALIS RECTUS. 


Fiff.  89. 


and  the  external  boundary  of  the  sheath.     The  sheath  contains  the 
rectus  and  pyramidalis  muscle. 

The  rectus  muscle  arises  by  a  flattened  tendon  from  the  crest  of 
the  OS  pubis,  and  is  inserted  into  the  cartilages  of  the  fifth,  sixth, 
and  seventh  ribs.    It  is  traversed  by  several  tendinous  zigzag  lines, 

called  lines  transversse.  One  of  these 
is  usually  situated  at  the  umbilicus, 
two  above  that  point,  and  sometimes 
one  belov^'.  They  are  vestiges  of  the 
abdominal  ribs  of  reptiles,  and  very 
rarely  extend  completely  through  the 
muscle. 

Relations. — By  its  external  surface 
v/ith  the  anterior  lamella  of  the  apo- 
neurosis of  the  internal  oblique,  below 
with  the  aponeurosis  of  the  transver- 
salis,  and  pyramidalis.  By  its  inter- 
nal surface  with  the  ensiform  carti- 
lage, the  cartilages  of  the  fifth,  sixth, 
seventh,  eighth  and  ninth  ribs,  with 
the  posterior  lamella  of  the  internal 
oblique,  the  peritoneum,  and  the  epi- 
gastric artery  and  veins. 

The  -pyramidalis  muscle  arises  from 
the  crest  of  the  os  pubis  in  front  of 
the  rectus,   and    is   inserted,  into  the 
linea  alba  at  about  midway  between 
the  umbilicus    and    the    pubis.     It  is 
enclosed  in  the  same  sheath  with  the 
rectus,*  and  rests  against  the  lower 
part  of  that  muscle.     This  muscle  is 
sometimes  wanting. 
The  rectus  may  now  be  divided  across  the  middle,  and  the  two 
ends  drawn  aside  for  the  purpose  of  examining  the  mode  of  forma- 
tion of  its  sheath. 

The  sheath  of  the  rectus  is  formed  in  front  for  the  upper  three- 
fourths  of  its  extent,  by  the  aponeurosis  of  the  external  oblique  and 
the  anterior  lamella  of  the  internal  oblique,  and  behind  by  the  poste- 


Fig.  80.  A  lateral  view  of  the  trunk  of  the  body,  showing  its  muscles,  and  particu- 
larly the  transvcrsalis  abdominis.  1.  The  costal  origin  of  the  latissimus  dorsi  muscle. 
2.  The  scrratiis  magnus.  3.  The  upper  part  of  the  external  oblique  muscle  divided  in 
the  direction  best  calculated  to  show  the  muscles  beneath  without  interfering  with  its 
indigitations  with  the  serratus  magnus.  4.  Two  of  the  external  intercostal  muscles. 
5.  Two  of  the  internal  intcrcoslals.  6.  The  transvorsalis  muscle.  7.  Its  posterior 
aponeurosis,  8.  Its  anterior  aponeurosis  forming  the  most  posterior  layer  of  the  slieath 
of  the  rectus.  9.  The  lower  part  of  the  left  rectus  with  the  aponeurosis  of  the  trans- 
vcrsalis passing  in  front.  10.  The  right  rectus  muscle.  II.  The  arched  opening  left 
between  the  lower  border  of  the  transvcrsalis  muscle  and  Poupart's  ligament,  through 
which  the  spermatic  cord  and  hernia  pass.  12.  ^I'lie  gluteus  maximus,  and  medius, 
and  tonsor  vaginae  fcmoris  muscles  invested  by  fascia  lata. 

*  This  is  not  precisely  the  fact,  as  there  is  a  separate  sheath  for  the  pyramidalis. — G, 


MUSCLES  OF  THE  ABDOMEN.  215 

rior  lamella  of  the  internal  oblique  and  the  aponeurosis  of  the  trans- 
versaHs.  At  the  commencement  of  the  lower  fourth,  the  posterior 
wall  of  the  sheath  terminates  in  a  thin  curved  margin,  the  aponeu- 
roses  of  the  three  muscles  passing  altogether  in  front  of  the  rectus. 

The  two  next  muscles  can  only  be  examined  when  the  whole  of 
the  viscera  are  removed.  To  see  the  quadratus  lumborum,  it  is  also 
necessary  to  divide  and  draw  aside  the  psoas  muscle  and  the  ante- 
rior lamella  of  the  aponeurosis  of  the  transversalis. 

The  quadratus  lumborum  muscle  is  concealed  from  view  by  the 
anterior  lamella  of  the  aponeurosis  of  the  transversalis  muscle,  which 
is  inserted  into  the  bases  of  the  transverse  processes  of  the  lumbar 
vertebrae,  and  ligamentum  arcuatum  externum.  When  this  lamella 
is  divided,  the  muscle  will  be  seen  arising  from  the  last  rib,  and 
from  the  transverse  processes  of  the  four  upper  lumbar  vertebrae. 
It  is  inserted  into  the  crest  of  the  ilium.  If  the  muscle  be  cut  across 
or  removed,  the  middle  lamella  of  the  transversalis  will  be  seen 
attached  to  the  apices  of  the  transverse  processes ;  the  quadratus 
being  enclosed  between  the  two  lamellae  as  in  a  sheath. 

Relations. — Enclosed  in  the  sheath  formed  by  the  transversalis 
muscle,  it  is  in  relation  in  front,  with  the  kidney,  the  colon,  the 
psoas  magnus  and  the  diaphragm.  Behind,  but  also  separated  by 
the  sheath,  with  the  erector  spinae. 

The  psoas  -parvus  arises  from  the  tendinous  arches  and  interverte- 
bral sustance  of  the  last  dorsal  and  first  lumbar  vertebrae,  and  ter- 
minates in  a  long  slender  tendon  which  is  inserted  into  the  pectineal 
line  of  the  os  pubis.  The  tendon  is  continuous  by  its  outer  border 
with  the  iliac  fascia. 

Relations. — It  rests  upon  the  psoas  magnus,  and  is  covered  in  by 
the  peritoneum  ;  superiorly  it  passes  beneath  the  ligamentum  arcu- 
atum of  the  diaphragm.     It  is  occasionally  wanting. 

Diaphragm. — To  obtain  a  good  view  of  this  important  inspiratory 
muscle,  the  peritoneum  should  be  dissected  from  its  under  surface. 
It  is  the  muscular  septum  between  the  thorax  and  abdomen,  and  is 
composed  of  two  portions,  a  greater  and  a  lesser  muscle.  The 
greater  muscle  arises  from  the  ensiform  cartilage ;  from  the  inner 
surfaces  of  the  six  inferior  ribs,  indigitating  with  the  transversalis ; 
and  from  the  ligamentum  arcuatum  externum  and  internum.  From 
these  points  which  form  the  internal  circumference  of  the  trunk,  the 
fibres  converge  and  are  inserted  into  the  central  tendon. 

The  ligamentum  arcuatum  externum  is  the  upper  border  of  the 
anterior  lamella  of  the  aponeurosis  of  the  transversalis :  it  arches 
across  the  origin  of  the  quadratus  lumborum  muscle,  and  is  attached 
by  one  extremity  to  the  extremity  of  the  transverse  process  of  the 
first  lumbar  vertebra,  and  by  the  other  to  the  apex  and  lower  margin 
of  the  last  rib. 

The  ligamentum  arcuatum  internum,  or  proprium,  is  a  tendinous 
arch  thrown  across  the  psoas  magnus  muscle  as  it  emerges  from 
the  chest.     It  is  attached  by  one  extremity  to  the  transverse  pro- 


216 


DIAPHRAGlff. 


cess  of  the  first  lumbar  vertebra,  and  by  the  other  to  the  body  of 
the  second. 

Fig.  90. 


The  tendinous  centre  of  the  diaphragm  is  shaped  like  a  trefoil  leaf, 
of  which  the  central  leaflet  points  to  the  ensiform  cartilage,  and  is 
the  largest ;  the  lateral  leaflets,  right  and  left,  occupy  the  correspond- 
ing portions  of  the  muscle ;  the  right  being  the  larger  and  more 
rounded,  and  the  left  smaller  and  lengthened  in  its  form. 

Between  the  sides  of  the  ensiform  cartilage  and  the  cartilages  of 
the  adjoining  ribs,  is  a  small  triangular  space  where  the  muscular 
fibres  of  the  diaphragm  are  deficient.  This  space  is  closed  only  by 
peritoneum  on  the  side  of  the  abdomen,  and  by  pleura  within  the 
chest.  It  is  therefore  a  weak  point,  and  a  portion  of  the  contents  of 
the  abdomen  might,  by  violent  exertion,  be  forced  through  it,  pro- 
ducing phrenic,  or  diaphragmatic  hernia. 

The  lesser  muscle  of  the  diaphragm  takes  its  origin  from  the  bodies 

Fig-.  90.  The  under  or  abdominal  side  of  the  diaphragm.  1,2,3.  The  greater  muscle ; 
the  figure  1  rests  upon  the  central  leaflet  of  the  tendinous  centre ;  the  number  2  on  the 
left  or  smallest  leaflet ;  and  number  3  on  the  right  leaflet.  4.  The  thin  fasciculus  which 
arises  from  the  ensiform  cartilage ;  a  small  triangular  space  is  left  on  either  side  of  tliis 
fasciculus,  which  is  closed  only  by  the  serous  membranes  of  the  abdomen  and  chest. 
.5.  The  ligamentum  arcuatum  externum  of  the  left  side.  6.  The  ligament um  arcuatum 
internum.  7.  A  small  arched  opening  occasionally  found,  through  which  the  lesser 
splanchnic  nerve  passes.  8.  The  right  or  larger  tendon  of  the  lesser  muscle  ;  a  muscu- 
lar fasciculus  from  this  tendon  curves  to  the  left  side  of  the  greater  muscle  between  the 
oesophageal  and  aortic  openings.  9.  The  fourth  *lumbar  vertebra.  10.  The  left  or 
shorter  tendon  of  the  lesser  muscle.  11.  The  aortic  opening  occupied  by  tlie  aorta, 
which  is  cut  short  off.  12.  A  portion  of  tlie  oesophagus  issuing  through  the  ccsoplia- 
geal  opening.  13.  The  opening  for  the  inferior  vena  cava,  in  the  tendinous  centre  of 
the  diaphragm.  14.  The  psoas  magnus  muscle  passing  beneath  the  ligamentum 
arcuatum  internum  :  it  has  been  removed  on  the  oppos-itc  side  to  show  the  arch  more 
distinctly,  l.").  The  quadratus  lumborum  passing  beneath  the  ligamentum  arcuatum 
externum  ;  this  muscle  has  also  been  removed  on  tlie  left  side. 


DIAPHRAGM.  *  217 

of  the  lumbar  vertebras  by  two  tendons.  The  right,  larger  and  longer 
than  the  left,  arises  from  the  anterior  surface  of  the  bodies  of  the 
second,  third,  and  fourth  vertebrae;  and  the  left  from  the  side  of  the 
second  and  third.  The  tendons  form  two  large  fleshy  bellies  {crura), 
which  ascend  to  be  inserted  into  the  central  tendon.  The  inner 
fasciculi  of  the  two  crura  cross  each  other  in  front  of  the  aorta,  and 
again  diverge  to  surround  the  oesophagus,  so  as  to  present  the  appear- 
ance of  a  figure  of  eight.  The  anterior  fasciculus  of  the  decussation 
is  formed  by  the  right  crus. 

The  openings  in  the  diaphragm  are  three :  one,  quadrilateral,  in 
the  tendinous  centre,  at  the  union  of  the  right  and  middle  leaflets, 
for  the  passage  of  the  inferior  vena  cava ;  a  muscular  opening  of  an 
elliptic  shape  formed  by  the  two  crura,  for  the  transmission  of  the 
cBSophagus  and  pneumogastric  nerves  ;  and  a  third,  the  aortic,  which 
is  formed  by  a  tendinous  arch  thrown  from  the  tendon  of  one  crus 
to  that  of  the  other,  across  the  vertebral  column,  beneath  which  pass 
the  aorta,  the  right  vena  azygos,  and  thoracic  duct.  The  great 
splanchnic  nerves  pass  through  openings  in  the  lesser  muscle  on 
each  side,  and  the  lesser  splanchnic  nerves  through  the  fibres  which 
arise  from  the  ligamentum  arcuatum  internum. 

Relations. — By  its  superior  surface  with  the  pleurae,  the  pericar- 
dium, the  heart,  and  the  lungs.  By  its  inferior  surface  with  the 
peritoneum ;  on  the  left  with  the  stomach  and  spleen ;  on  the  right 
with  the  convexity  of  the  liver ;  and  behind  with  the  kidneys,  the 
suprarenal  capsules,  the  duodenum  and  the  solar  plexus.  By  its 
circumference  with  the  ribs  and  intercostal  muscles,  and  with  the 
vertebral  column. 

Actions. — The  external  oblique  muscle,  acting  singly,  would  draw 
the  thorax  towards  the  pelvis,  and  twist  the  body  to  the  opposite 
side.  Both  muscles,  acting  together,  would  flex  the  thorax  directly 
on  the  pelvis.  The  internal  obhque  of  one  side  draws  the  chest 
downwards  and  outwards :  both  together  bend  it  directly  forwards. 
Either  transversalis  muscle,  acting  singly,  will  diminish  the  size  of 
the  abdomen  on  its  own  side,  and  both  together  will  constrict  the 
entire  cylinder  of  the  cavity.  The  recti  muscles,  assisted  by  the 
pyramidales,  flex  the  thorax  upon  the  chest,  and,  through  the  me- 
dium of  the  lineae  transversae,  are  enabled  to  act  when  their  sheath  is 
curved  inwards  by  the  action  of  the  transversales.  The  pyramidales 
are  tensors  of  the  linea  alba.  The  abdominal  are  expiratory  mus- 
cles, and  the  chief  agents  of  expulsion ;  by  their  action  the  foetus  is 
expelled  from  the  uterus,  the  urine  from  the  bladder,  the  faeces  from 
the  rectum,  the  bile  from  the  gall-bladder,  the  ingesta  from  the  sto- 
mach and  bowels  in  vomiting,  and  the  mucus  and  irritating  sub- 
stances from  the  bronchial  tubes,  trachea,  and  nasal  passages  during 
coughing  and  sneezing.  To  produce  these  efforts  they  all  act  to- 
gether. Their  violent  and  continued  action  produces  hernia  ;  and, 
acting  spasmodically,  they  may  occasion  rupture  of  the  viscera. 
The  quadratus  lumborum  draws  the  last  rib  downwards,  and  is  an 
expiratory  muscle ;  it  also  serves  to  bend  the  vertebral  column  to 

19 


218  MUSCLES  OF  THE  PERINEUM. 

one  or  the  other  side.  The  psoas  parvus  is  a  tensor  of  the  iliac 
fascia,  and,  taking  its  fixed  origin  from  below,  it  may  assist  in  flex- 
ing the  vertebral  column  forwards.  The  diaphragm  is  an  inspira- 
tory muscle,  and  the  sole  agent  in  tranquil  inspiration.  When  in 
action,  the  muscle  is  drawn  downwards,  its  plane  being  rendered 
oblique  from  the  level  of  the  ensiform  cartilage,  to  that  of  the  upper 
lumbar  vertebra.  During  relaxation  it  is  convex,  and  encroaches 
considerably  on  the  cavity  of  the  chest,  particularly  at  the  sides, 
where  it  corresponds  with  the  lungs.  It  assists  the  abdominal  mus- 
cles powerfully  in  expulsion,  every  act  of  that  kind  being  preceded 
or  accompanied  by  a  deep  inspiration.  Spasmodic  action  of  the 
diaphragm  produces  hiccough  and  sobbing,  and  its  rapid  alternation 
of  contraction  and  relaxation,  combined  with  laryngeal  and  facial 
movements,  laughing  and  crying. 

Muscles  of  the  Perineum. 

The  muscles  of  the  perineum  are  situated  in  the  outlet  of  the  pel- 
vis, and  consist  of  two  groups,  one  of  which  belongs  especially  to 
the  organs  of  generation  and  urethra,  the  other  to  the  termination 
of  the  alimentary  canal.  To  these  may  be  added  the  only  pair  of 
muscles  which  is  proper  to  the  pelvis,  the  coccygeus.  The  muscles 
of  this  region  in  the  male,  are  the 

Accelerator  urinas, 
Erector  penis, 
Transversus  perinei. 
Compressor  urethrse, 
Sphincter  ani, 
Levator  ani, 
Coccygeus. 

Dissection. — To  dissect  the  perineum,  the  subject  should  be  fixed 
in  the  position  for  lithotomy,  that  is,  the  hands  should  be  bound  to 
the  soles  of  the  feet,  and  the  knees  kept  apart.  An  easier  plan  is  the 
drawing  of  the  feet  upwards  by  means  of  a  cord  passed  through  a 
hook  in  the  ceiling.  Both  of  these  plans  of  preparation  have  for 
their  object  the  full  exposure  of  the  perineum.  And  as  this  is  a 
dissection  which  demands  some  degree  of  delicacy  and  nice  manipu- 
lation, a  strong  light  should  be  thrown  upon  the  part.  Having  fixed 
the  subject,  and  drawn  the  scrotum  upwards  by  means  of  a  string 
or  hook,  carry  an  incision  from  the  base  of  the  scrotum  along  the 
ramus  of  the  pubis  and  ischium  and  tuberosity  of  the  ischium,  to  a 
point  parallel  with  the  apex  of  the  coccyx ;  then  describe  a  curve 
over  the  coccyx  to  the  same  point  on  the  opposite  side,  and  continue 
the  incision  onwards  along  the  opposite  tuberosity,  and  along  the 
ramus  of  the  ischium  and  of  the  pubis,  to  the  opposite  side  of  the 
scrotum,  where  the  two  extremities  may  be  connected  by  a  trans- 
verse incision.  This  incision  will  completely  surround  the  perineum, 
following  very  nearly  the  outline  of  its  boundaries.    Now  let  the  stu- 


MUSCLES  OF  THE  PERINEUM.  219 

dent  dissect  off  the  integument  carefully  from  the  whole  of  the  in- 
cluded space,  and  he  will  expose  the  fatty  cellular  structure  of  the 
common  superficial  fascia,  which  exactly  resembles  the  superficial 
fascia  in  every  other  situation.  The  common  superficial  fascia  is 
then  to  be  removed  to  the  same  extent,  exposing  the  superficial 
perineal  fascia.  This  layer  is  also  to  be  turned  aside,  when  the 
muscles  of  the  genital  region  of  the  perineum  will  be  brought  into 
view. 

The  Acceleratores  urince  arise  from  a  tendinous  point  in  the  centre 
of  the  perineum  and  from  the  raphe.  From  these  origins  the  fibres 
diverge,  like  the  plumes  of  a  pen:  the  posterior  fibres  to  be  inserted 
into  the  ramus  of  the  pubis  and  ischium  ;  the  middle  to  encircle  the 
corpus  spongiosum,  and  meet  upon  its  upper  side;  and  the  anterior 
to  spread  out  upon  the  corpus  cavernosum  on  each  side,  and  be 
inserted,  partly  into  its  fibrous  structure,  and  partly  into  the  fascia 
of  the  penis.  The  posterior  and  middle  insertions  of  these  muscles 
are  best  seen,  by  carefully  raising  one  muscle  from  the  corpus  spon- 
giosum and  tracing  its  fibres. 

Relations. — By  their  superficial  surface  with  the  superficial  peri- 
neal fascia,  the  dartos,  the  superficial  vessels  and  nerves  of  the  peri- 
neum, and  on  each  side  with  the  erector  penis.  By  their  deep  sur- 
face with  the  corpus  spongiosum  and  bulb  of  the  urethra. 

The  Erector  penis  arises  from  the  ramus  and  tuberosity  of  the 
ischium,  and  curves  around  the  root  of  the  penis,  to  be  inserted  into 
the  upper  surface  of  the  corpus  cavernosum,  where  it  is  continuous 
with  a  strong  fascia  which  covers  the  dorsum  of  the  organ,  the 
fascia  penis. 

Relations. — By  its  superficial  surface  with  the  superficial  perineal 
fascia,  the  dartos,  and  the  superficial  perineal  vessels  and  nerve.  By 
its  deep  surface  with  the  corpus  cavernosum  penis. 

The  Transversus  perinei  arises  from  the  tuberosity  of  the  ischium 
on  each  side,  and  is  inserted  into  the  central  tendinous  point  of  the 
perineum.* 

Relations. — By  its  superficial  surface  with  the  superficial  perineal 
fascia,  and  superficial  perineal  artery.  By  its  deep  surface  with 
the  deep  perineal  fascia,  and  internal  pudic  artery  and  veins.  By  its 
posterior  border  it  is  in  relation  with  that  portion  of  the  superficial 
perineal  fascia  which  passes  back  to  become  continuous  with  the 
deeo  fascia. 

TO  dissect  the  compressor  urethrcB,  the  whole  of  the  preceding 
muscles  should  be  removed,  so  as  to  render  the  glistening  surface 
of  the  deep  perineal  fascia  quite  apparent.  The  anterior  layer  of 
this  fascia  should  then  be  carefully  dissected  away,  and  the  corpus 

*  I  once  dissected  a  perineum  in  which  the  transversus  perinei  was  of  large  size,  and 
spread  out  as  it  approached  the  middle  line  so  as  to  become  fan-shaped.  The  posterior 
fibres  were  continuous  with  those  of  the  muscle  of  the  opposite  side;  but  the  anterior 
were  continued  forwards  upon  the  bulb  and  corpus  spongiosum  of  the  urethra  as  far  as 
the  middle  of  the  penis,  forming  a  broad  layer  which  usurped  the  place  and  office  of  the 
accelerator  urince. 


220 


MUSCLES  OF  THE  PERINEUM. 


spongiosum  penis  divided  through  its  middle,  separated  from  the 
corpus  cavernosum,  and  drawn  forwards,  to  put  the  membranous 
portion  of  the  urethra,  upon  which  the  muscle  is  spread  out,  upon 
the  stretch.  The  muscle  is,  however,  better  seen  in  a  dissection 
made  from  within  the  pelvis,  after  having  turned  down  the  bladder 
from  its  attachment  to  the  os  pubis,  and  removed  a  plexus  of  veins 
and  the  posterior  layer  of  the  deep  perineal  fascia. 

Fig.  91. 


The  Compressor  urethrcB  (Wilson's  and  Guthrie's  muscles),  con- 
sists of  two  portions;  one  of  which  is  transverse  in  its  direction,  and 
passes  inwards,  to  embrace  the  membranous  urethra  ;  the  other  is 
peiyendicular,  and  descends  from  the  pubis,  l^he  transverse  portion, 
particularly  described  by  Mr.  Guthrie,  arises  by  a  narrow  tendinous 
point,  from  the  upper  part  of  the  ramus  of  the  ischium,  on  each 
side,  and  divides  into  two  fasciculi,  which  pass  inwards  and  slightly 
upwards,  and  embrace  the  membranous  portion  of  the  urethra  and 
Cowper's  glands.  As  they  pass  towards  the  urethra,  they  spread 
out  and  become  fan-shaped,  and  are  inserted  into  a  tendinous  raphe 
upon  the  upper  and  lower  surfaces  of  the  urethra,  extending  from 
the  apex  of  the  prostate  gland,  to  which  they  are  attached  poste- 
riorly, to  the  bulbous  portion  of  the  urethra,  with  which  they  are 
connected  in  front.  When  seen  from  above,  these  portions  resemble 
two  fans,  connected  by  their  expanded  border  along  the  middli^ine 
of  the  membranous  urethra,  from  the  prostate  to  the  bulbous  ponion 
of  the  urethra.  The  same  appearance  is  obtained  by  viewing  them 
from  below. 

Fi^.  91.  The  muscles  of  the  perineum.  1.  The  acccleratorcs  urinse  muscles;  the 
fijTurc  rests  upon  the  corpus  spongiosum  penis,  2.  Tiie  corpus  cavernosum  of  one 
side.  3.  The  erector  penis  ot  one  side.  4.  The  trarisversus  pcrinei  of  one  side.  5.  The 
trianjrular  space  throuj^h  which  the  deep  pcri^eal  fascia  is  seen.  6.  The  sphincter  ani  ; 
its  iinterior  extremity  is  cut  off.  7.  The  levator  ani  of  tlie  left  side;  the  deep  space 
beUveeii  the  tuberosity  of  the  ischium  (8)  and  the  anus,  is  the  iscJiio-rectal  fossa;  the 
•  same  fossa  is  seen  upon  the  opposite  side.  9.  The  spine  of  the  ischium.  .  10.  The  left 
coceygeus  muscle.    The  boundaries  of  the  perineum  are  well  seen  in  this  engraving. 


SPHINCTER  ANI LEVATOR  ANI.  221 

The  perpendicular  fortiori*  described  by  Mr.  Wilson,  arises  by 
two  tendinous  points  from  the  inner  surface  of  the  arch  of  the  pubis, 
on  each  side  of,  and  close  to  the  symphysis.  The  tendinous  origins 
soon  become  muscular,  and  descend  perpendicularly,  to  be  inserted 
into  the  upper  fasciculus  of  the  transverse  portion  of  the  muscle;  so 
that  it  is  not  a  distinct  muscle  surrounding  the  membranous  portion 
of  the  urethra,  and  supporting  it  as  in  a  sling,  as  described  by  Mr. 
Wilson,  but  merely  an  upper  origin  of  the  transverse  muscle. 

The  compressor  urethrae  may  be  considered  either  as  two  sym- 
metrical muscles  meeting  at  the  raphe",  or  as  a  single  muscle :  I 
have  adopted  the  latter  course  in  the  above  description,  as  appearing 
to  me  the  more  consistent  with  the  general  connexions  of  the  muscle, 
and  with  its  actions. 

The  Sphincter  ani  is  a  thin  and  elliptical  plane  of  muscle,  closely 
adherent  to  the  integument,  and  surrounding  the  opening  of  the 
anus.  It  arises  posteriorly  in  the  superficial  fascia  around  the 
coccyx,  and  by  a  fibrous  raphe  from  the  apex  of  that  bone ;  and  is 
inserted  anteriorly  into  the  tendinous  centre  of  the  perineum,  and 
into  the  raphe  of  the  integument,  nearly  as  far  forwards  as  the 
commencement  of  the  scrotum. 

Relations. — By  its  superficial  surface  with  the  integument.  By 
its  deep  surface  with  the  internal  sphincter,  the  levator  ani,  the  cel- 
lular tissue  and  fat  in  the  ischio-rectal  fossa,  and  in  front  with  the 
super-ficial  perineal  fascia. 

The  Sphincter  ani  internus  is  a  muscular  ring  embracing  the 
extremity  of  the  intestine,  and  formed  by  an  aggregation  of  the  cir- 
cular muscular  fibres  of  the  rectum. 

Part  of  the  levator  ani  may  be  seen  during  the  dissection  of  the 
anal  portion  of  the  perineum  by  removing  the  fat  which  surrounds 
the  termination  of  the  rectum  in  the  ischio-rectal  fossa.  But  to  study 
the  entire  muscle,  a  lateral  section  of  the  pelvis  must  be  made  by 
sawing  through  the  pubis  a  little  to  one  side  of  the  symphysis,  sepa- 
rating the  bones  behind  at  the  sacro-iliac  symphysis,  and  turning 
down  the  bladder  and  rectum.  The  pelvic  fascia  is  then  to  be  care- 
fully raised,  beginning  at  the  base  of  the  bladder  and  proceeding 
upwards,  until  the  whole  extent  of  the  muscle  be  exposed. 

The  Levator  ani  is  a  thin  plane  of  muscular  fibres,  situated  on 
each  side  of  the  pelvis.  It  arises  from  the  inner  surface  of  the  os 
pubis,  from  the  spine  of  the  ischium,  and  between  those  points  from 
the  angle  of  division  between  the  obturator  and  the  pelvic  fascia. 
Its  fibres  descend  to  be  inserted  into  the  extremity  of  the  coccyx 
into  a  fibrous  raphe  in  front  of  that  bone,  into  the  lower  part  of  the 
rectum,  base  of  the  bladder,  and  prostate  gland. 

*  Mr.  Tyrrell,  who  has  made  many  careful  dissections  of"  the  muscles  of  the  perineum, 
has  not  observed  this  portion  of  the  muscle ;  he  considers  Wilson's  muscle  (with  some 
other  anatomists)  to  be  the  anterior  fibres  of  the  levator  ani,  not  uniting  beneath  the 
urethra  as  described  by  Mr.  Wilson ;  but  inserted  into  a  portion  of  the  pelvic  fascia 
situated  between  the  prostate  gland  and  rectum, — the  recto-vesical  fascia. 

19* 


222  MUSCLES  OF  THE  PERINEUM. 

In  the  female  this  muscle  is  inserted  into  the  coccyx  and  -fibrous 
raphe,  extremity  of  the  rectum  and  vagina. 

Relations. — By  its  external  or  ferineal  surface,  with  a  thin  layer  • 
of  fascia,  by  which  and  by  the  obturator  fascia  it  is  separated  from 
the  obturator  internus  muscle ;  with  the  fat  in  the  ischio-rectal  fossa, 
the  deep  perineal  fascia,  the  levator  ani,  and  posteriorly  with  the 
gluteus  maximus.  By  its  internal  or  pelvic  surface,  with  the  pelvic 
fascia,  which  separates  it  from  the  viscera  of  the  pelvis  and  peri- 
toneum. 

The  Coccygeus  muscle  is  a  tendino-muscular  layer  of  a  triangular 
form.  It  arises  from  the  spine  of  the  ischium,  and  is  inserted  into 
the  side  of  the  coccyx  and  lower  part  of  the  sacrum. 

Relations. — By  its  internal  or  pelvic  surface,  with  the  rectum ;  by 
its  external  surface  with  the  lesser  and  greater  sacro-ischiatic  liga- 
ments. 

The  muscles  of  the  perineum  in  the  female  are  the  same  as  in  the 
male,  and  have  received  analogous  names.     They  are  smaller  in 
size,  and   are  modified  to  suit  the  different  form  of  the  organs; 
they  are- 
Constrictor  vaginae, 

Erector  clitoridis, 

Transversus  perinei, 

Compressor  urethrae, 

Sphincter  ani,  * 

Levator  ani, 

Coccygeus. 

The  Constrictor  vagincs  is  analogous  to  the  acceleratores  urinse ; 
it  is  continuous  posteriorly  with  the  sphincter  ani,  interlacing  with 
its  fibres,  and  is  inserted  anteriorly  into  the  sides  of  the  corpora 
cavernosa,  and  fascia  of  the  clitoris. 

The  Transversus  perinei  is  inserted  into  the  side  of  the  constrictor 
vaginae,  and  the  levator  ani  into  the  side  of  the  vagina. 

The  other  muscles  are  precisely  similar  in  their  attachments  to 
those  in  the  male. 

Actions. — The  acceleratores  urinae  being  continuous  at  the  middle 
line,  and  attached  on  each  side  to  the  bone,  by  means  of  their  pos- 
terior fibres  will  support  the  bulbous  portion  of  the  urethra,  and  act- 
ing suddenly  will  propel  the  semen,  or  the  last  drops  of  urine  from 
the  canal.  The  posterior  and  middle  fibres,  according  to  Krause,* 
contribute  towards  the  erection  of  the  corpus  spongiosum,  by  pro- 
ducing compression  upon  the  venous  structure  of  the  bulb ;  and  the 
anterior  fibres,  according  to  Tyrrell,f  assist  in  the  erection  of  the 
entire  organ  by  compressing  the  vena  dorsalis,  by  means  of  their 
insertion  into  the  fascia  penis.     The  erector  penis  becomes  entitled 

»  jWoller,  Archiv  fUr  Anatomie,  Physifllogie,  &c.  1837. 
+  Lectures  in  the  College  of  Surgeons.    1839. 


MUSCLES  OF  THE  UPPER  EXTREMITY.  223 

to  its  name  from  spreading  out  upon  the  dorsum  of  the  organ,  into  a 
membranous  expansion  (fascia  penis),  which,  according  to  Krause, 
compresses  the  dorsal  vein  during  the  action  of  the  muscle,  and 
especially  after  the  erection  of  the  organ  has  commenced.  The 
transverse  muscles  serve  to  steady  the  tendinous  centre,  that  the 
muscles  attached  to  it  may  obtain  a  firm  point  of  support.  Accord- 
ing to  Cruveilhier,  they  draw  the  anus  backwards  during  the  expul- 
sion of  the  faeces,  and  antagonize  the  levatores  ani  which  carry  the 
anus  forwards.  The  compressor  urethrse,  taking  its  fixed  point 
from  the  ramus  of  the  ischium  at  each  side,  can,  says  Mr..Guthrie, 
*'  compress  the  urethra  so  as  to  close  it ;  I  conceive,  completely 
after  the  manner  of  a  sphincter."  The  transverse  portion  will  also 
have  a  tendency  to  draw  the  urethra  downwards,  whilst  the  per- 
pendicular portion  will  draw  it  upwards  towards  the  os  pubis.  The 
♦inferior  fasciculus  of  the  transverse  muscle,  enclosing  Cowper's 
glands,  will  assist  those  bodies  in  evacuating  their  secretion.  The 
external  sphincter  being  a  cutaneous  muscle  contracts  the  integu- 
ment around  the  anus,  and  by  its  attachments  to  the  tendinous 
centre,  and  to  the  point  of  the  coccyx,  assists  the  levator  ani  in 
giving  support  to  the  opening  during  expulsive  efforts.  The  internal 
sphincter  contracts  the  extremity  of  the  cylinder  of  the  intestine. 
The  use  of  the  levator  ani  is  expressed  in  its  name.  It  is  the 
antagonist  of  the  diaphragm  and  the  rest  of  the  expulsory  muscles, 
and  serves  to  support  the  rectum  and  vagina  during  their  expulsive 
efforts.  The  levator  ani  acts  in  unison  with  the  diaphragm,  and 
rises  and  falls  like  that  muscle  in  forcible  respiration.  Yielding  to 
the  propulsive  action  of  the  abdominal  muscles,  it  enables  the  outlet 
of  the  pelvis  to  bear  a  greater  force  than  a  resisting  structure,  and 
on  the  remission  of  such  actions  it  restores  the  perineum  to  its 
original  form.  The  coccygei  muscles  restore  the  coccyx  to  its 
natural  position,  after  it  has  been  pressed  backwards  during  defse- 
cation  or  during  parturition. 

MUSCLES     OF     THE     UPPER     EXTREMITY. 

The  muscles  of  the  upper  extremity  maybe  arranged  into  groups 
corresponding  with  the  different  regions  of  the  limb  thus: 

Anterior  thoracic  region.  Lateral  thoracic  region. 

Pectoralis  major,  Serratus  magnus. 

Pectoralis  minor, 
Subclavius. 

Anterior  scapular  region.  Posterior  scapular  region. 

Subscapularis.  Supra-spinatus, 

Infra-spinatus, 
Teres  minor,     . 
Teres  major, 

Acromial  region. 
Deltoid. 


224 


MUSCLES  OF  THE  UPPER  EXTREMITY. 


Anterior  huineral  region. 

Coraco-brachialis, 
Biceps, 
Brachials  anticus. 

Anterior  brachial  region. 

Superficial  layer. 

Pronator  radii  teres, 
Flexor  carpi  radialis, 
Palmaris  longus, 
Flexor  sublimis  digitorum, 
Flexor  carpi  ulnaris. 


Deep  layer. 

Flexor  profundus  digitorum, 
Flexor  longus  pollicis. 
Pronator  quadratus. 


Posterior  humeral  region. 
Triceps. 


Posterior  brachial  region. 

Superficial  layer. 

Supinator  longus, 
Extensor  carpi  radialis  longior, 
Extensor  carpi  radialis  brevior, 
Extensor  communis  digitorum, 
Extensor  minimi  digiti, 
Extensor  carpi  ulnaris, 
Anconeus.  • 

Deep  layer. 

Supinator  brevis. 
Extensor  ossis  metacarpi  pollicis. 
Extensor  primi  internodii  pollicis, 
Extensor  secundi  internodii  pol- 
licis. 
Extensor  indicis. 


HAND. 


Radial  region. 


Ulnar  region. 


Abductor  pollicis,  Palmaris  brevis, 

Flexorossis  metacarpi  (opponens),  Abductor  minimi  digiti, 
Flexor  brevis  pollicis,  Flexor  brevis  minimi  digiti, 

Abductor  pollicis.  Adductor  minimi  digiti. 

Palmar  region. 
Lumbricales, 
Interossei  palmares, 
Interossei  dorsales. 


Anterior  thoracic  region. 

Pectoralis  major, 
Pectoralis  minor, 
Subclavius. 

Dissection. — Make  an  incision  along  the  line  of  the  clavicle,  from 
the  upper  part  of  the  sternum  to  the  acromion  process ;  a  second 
along  the  lower  border  of  the  great  pectoral  muscle,  from  the  lower 
end  of  the  sternum  to  the  insertion  of  its  tendon  into  the  humerus ; 
and  connect  the  two  by  a  third,  carried  longitudinally  along  the 
middle  of  the  sternum.  The  integument  and  superficial  fascia  are 
to  be  dissected  together  from  off  the  fibres  of  the  muscle,  and  always 


FECTORALIS  MAJOR  AND  MINOE.  225 

in  the  direction  of  their  course.  For  this  purpose  the  dissector,  if 
he  have  the  right  arm,  will  commence  with  the  lower  angle  of  the 
flap ;  if  the  left,  with  the  upper  angle.  He  will  thus  expose  the  pec- 
toralis  major  muscle  in  its  whole  extent. 

The  Pectoralis  mr/^or  muscle  arises  from  the  sternal  two-thirds  of 
the  clavicle,  from  one  half  the  breadth  of  the  sternum  its  whole  length, 
and  from  the  cartilages  of  all  the  true  ribs,  excepting  the  first.  It 
is  inserted  by  a  broad  tendon  into  the  anterior  bicipital  ridge. of  the 
humerus. 

That  portion  of  the  muscle  which  arises  from  the  clavicle,  is  sepa- 
rated from  that  connected  with  the  sternum  by  a  distinct  cellular 
interspace;  hence  we  speak  of  the  c/ayzcM/ar  portion  and  sternal  por- 
tion of  the  pectoralis  major.  The  fibres  from  this  very  extensive 
origin  converge  towards  a  narrow  insertion,  giving  the  muscle  a 
radiated  appearance.  But  there  is  a  peculiarity  about  the  forma- 
tion of  its  tendon  which  must  be  carefully  noted.  The  whole  of  the 
lower  border  is  folded  inwards  upon  the.  upper  portion,  so  that  the 
tendon  is  doubled  upon  itself.  Another  peculiarity  results  from  this 
arrangement :  the  fibres  of  the  upper  portion  of  the  muscle  are  in- 
serted into  the  lower  part  of  the  ridge  ;  and  those  of  the  lower  por- 
tion, into  the  upper  part. 

Relations. — By  its  external  surface  with  the  fibres  of  origin  of  the 
platysma  myoides,  the  mammary  gland,  the  superficial  fascia  and 
integument.  By  its  internal  surface,  on  the  thorax,  with  the  clavicle, 
the  sternum,  the  costal  cartilages,  intercostal  muscles,  subclavius, 
pectoralis  minor,  and  serratus  magnus ;  in  the  axilla,  with  the  axil- 
lary vessels  and  glands.  By  its  external  border  with  the  deltoid, 
from  which  it  is  separated  by  a  cellular  interspace  lodging  the 
cephalic  vein  and  the  descending  branch  of  the  thoracico-acromialis 
artery.  Its  loiver  border  forms  the  anterior  boundary  of  the  axillary 
space. 

The  pectoralis  major  is  now  to  be  removed  by  dividing  its  fibres 
along  the  lower  border  of  the  clavicle,  and  then  carrying  the  inci- 
sion perpendicularly  downwards,  parallel  to  the  sternum,  and  at 
about  three  inches  from  its  border.  Divide  some  loose  cellular 
tissue,  and  several  small  branches  of  the  thoracic  arteries,  and  re- 
flect the  muscle  outwards.  We  thus  bring  into  view  a  region  of, 
considerable  interest,  in  the  middle  of  which  is  situated  the  pectoralis 
minor. 

The  Pectoralis  minor  arises  by  three  digitations  from  the  third, 
fourth,  and  fifth  ribs,  and  is  inserted  into  the  anterior  border  of  the 
coracoid  process  of  the  scapula  by  a  broad  tendon. 

Relations. — By  its  anterior  surface  with  the  pectoralis  major  and 
superior  thoracic  vessels  and  nerves.  By  its  j)osterior  surface  with 
the  ribs,  the  intercostal  muscles,  serratus  magnus,  axillary  space, 
and  axillary  vessels  and  nerves.  Its  upper  border  forms  the  lower 
boundary  of  a  triangular  space  bounded  above  by  the  costo-coracoid 
membrane,'  and  internally,  by  the  ribs.  In  this  space  are  found  the 
axillary  vessels  and  nerves,  and  in  it  the  subclavian  artery  is  tied 
below  the  clavicle. 


226  LATERAL  THOBACIC  REGION. 

The  Subclavius  muscle  arises  by  a  I'ound  tendon  from  the  cartilage 

of  the  first  rib,  and  is  inserted  into  the  under  surface  of  the  clavicle. 
This  muscle  is  concealed  by  the  costo-coracoid  membrane,  an  ex- 
tension of  the  deep  cervical  fascia,  by  which  it  is  invested. 

Relations. — By  its  upper  surface  with  the  clavicle.  By  the  lower 
with  the  subclavian  artery  and  vein,  and  brachial  plexus,  which 
separate  it  from  the  first  rib.  In  front  with  the  pectoralis  major, 
the  costo-coracoid  membrane  being  interposed. 

Actions. — The  pectoralis  major  draws  the  arm  against  the  thorax, 
while  its  upper  fibres  assist  the  upper  part  of  the  trapezius  in  raising 
the  shoulder,  as  in  supporting  weights.  The  lower  fibres  depress 
the  shoulder  with  the  aid  of  the  latissimus  dorsi.  Taking  its  fixed 
point  from  the  shoulder,  the  pectoralis  major  assists  the  pectoralis 
minor,  subclavius,  and  serratus  magnus,  in  drawing  up  and  expand- 
ing the  chest.  The  pectoralis  minor,  in  addition  to  this  action, 
draws  upon  the  coracoid  process,  and  assists  in  rotating  the  scapula 
upon  the  chest.  The  subclavius  draws  the  clavicle  downwards  and 
forwards,  and  thereby  assists  in  steadying  the  shoulder.  All  the 
muscles  of  this  group  are  agents  in  forced  respiration,  but  are  unable 
to  act  until  the  shoulders  be  fixed. 

Lateral  thoracic  region. 
Serratus  magnus. 

The  Sen^atus  magnus  (serratus,  indented  like  the  edge  of  a  saw,) 
arises  by  fleshy  serrations  from  the  nine  upper  ribs  excepting  the 
first,  and  extends  backwards  upon  the  side  of  the  chest,  to  be  inserted 
into  the  whole  length  of  the  base  of  the  scapula.  It  indigitates  by 
means  of  its  five  lower  serrations  with  the  obliquus  externus  abdo- 
minis. 

Relations. — By  its  superficial  surface  with  the  pectoralis  major 
and  minor,  the  subscapularis,  and  the  axillary  vessels  and  nerves. 
By  its  deej)  surface  with  the  ribs  and  intercostal  muscles,  to  which 
it  is  connected  by  an  extremely  loose  cellular  tissue. 

Actions. — The  serratus  magnus  is  the  great  external  inspiratory 
muscle,  raising  the  ribs  when  the  shoulders  are  fixed,  and  thereby 
increasing  the  cavity  of  the  chest.  Acting  upon  the  scapula,  it 
draws  the  shoulder  forwards,  as  we  see  to  be  the  case  in  diseased 
lungs,  where  the  chest  has  become  almost  fixed  from  apprehension 
of  the  expanding  action  of  the  respiratory  muscles. 

Anterior  scapular  region. 

Subscapularis. 

The  Suhscapularis  muscle  arises  from  the  whole  of  the  under 
surface  of  the  scapula  excepting  the  superior  angle,  and  terminates 
by  a  broad  and  thick  tendon,  which  is  inserted  into  the  lesser  tube- 


POSTERIOR  SCAPULAR  REGION.  227 

rosity  of  the  humerus.  The  tendon  of  this  muscle  forms  a  part  of 
the  capsule  of  the  joint,  glides  over  a  large  bursa  which  separates 
it  from  the  base  of  the  coracoid  process,  and  is  lined  by.  a  prolonga- 
tion of  the  synovial  membrane  of  the  articulation. 

Relations. — By  its  anterior  surface  with  the  serratus  magnus,  the 
coraco-brachialis,  deltoid,  and  with  the  axillary  vessels  and  nerves. 
By  its  posterior  surface  with  the  scapula,  the  subscapular  vessels 
and  nerves,  and  the  shoulder  joint. 

Motions. — It  rotates  the  head  of  the  humerus  inwards,  and  is  a 
powerful  defence  to  .the  joint.  When  the  arm  is  raised,  it  draws 
the  humerus  downwards. 

Posterior  scapular  region. 
Supra-spinatus,  Teres  minor, 

Infra-spinatus,  Teres  major. 

lihe  Supra-spinatus  m\x?,Q\e,  {supra,  above;  5pz"/?a,  the  spine)  arises 
from  the  whole  of  the  supra-spinous  fossa,  and  is  inserted  into  the 
uppermost  depression  on  the  great  tuberosity  of  the  humerus.  The 
tendon  of  this  muscle  cannot  be  well  seen  without  cutting  away  the 
acromion  process  with  a  saw. 

Relations. — By  its  upper  surface  with  the  trapezius,  the  clavicle, 
acromion,  and  coraco-acromial  ligament.  From  the  trapezius  it  is 
separated  by  a  strong  fascia.  By  its  lower  surface  with  the  supra- 
spinous fossa,  the  supra-scapular  vessels  and  nerve,  and  the  upper 
part  of  the  shoulder  joint,  forming  part  of  the  capsular  ligament. 

The  Ivfra-spinatus  {infra,  beneath ;  spina,  the  spine,)  is  covered 
in  by  a  layer  of  tendinous  fascia,  which  must  be  removed  before  the 
fibres  of  the  muscle  can  be  seen,  the  deltoid  muscle  having  been 
previously  turned  down  from  its  scapular  origin.  It  arises  from  the 
whole  of  the  infra-spinous  fossa,  and  from  the  fascia  above-mentioned, 
and  is  inserted  into  the  middle  depression  upon  the  greater  tuberosity 
of  the  humerus. 

Relations. — By  its  posterior  surface  with  the  deltoid,  latissimus 
dorsi  and  integument.  By  its  anterior  surface  with  the  infra-spinous 
fossa,  superior  and  dorsal  scapular  vessels,  and  shoulder  joint ;  its 
tendon  being  lined  by  a  prolongation  from  the  synovial  membrane. 
By  its  upper  border  it  is  in  relation  with  the  spine  of  the  scapula, 
and  by  the  lower  with  the  teres  minor,  with  which  it  is  closely 
united. 

The  Teres  minor  muscle  {teres,  round)  arises  from  the  middle 
third  of  the  inferior  border  of  the  scapula,  and  is  inserted  into  the 
lower  depression  on  the  great  tuberosity  of  the  humerus.  The  ten- 
dons of  these  three  muscles,  with  that  of  the  subscapularis,  are  in 
immediate  contact  with  the  joint,  and  form  part  of  its  ligamentous 
capsule,  thereby  preserving  the  solidity  of  the  articulation.  They 
are  therefore  the  structures  most  frequently  ruptured  in  dislocation 
of  the  shoulder  joint  with  violence. 

Relations. — By  its  posterior  surface  with  the  deltoid,  latissimus 
dorsi  and  integument.    By  its  anterior  surface  with  the  inferior  bor- 


228  ACEOJIIAL  REGION DELTOID. 

der  and  part  of  the  dorsum  of  the  scapula,  the  dorsalis  scapulae  ves- 
sels, scapular  head  of  the  triceps,  and  shoulder  joint.  By  its  upfer 
border  with  the  infra-spinatus  ;  and  by  the  lower  with  the  latissimus 
dorsi,  teres  major,  and  long  head  of  tiie  triceps. 

The,  Teres  major  muscle  arises  from  the  lower  third  of  the  inferior 
border  of  the  scapula,  encroaching  a  little  upon  its  dorsal  aspect,  and 
is  inserted  into  the  posterior  bicipital  ridge.  Its  tendon  lies  imme- 
diately behind  that  of  the  latissimus  dorsi,  from  which  it  is  separated 
by  a  synovial  membrane. 

Relations. — By  its  posterior  surface  with  the  latissimus  dorsi,  sca- 
pular head  of  the  triceps  and  integument.  By  its  anterior  surface 
with  the  subscapularis,  latissimus  dorsi,  coraco-brachialis,  short  head 
of  the  biceps,  axillary  vessels,  and  branches  of  the  brachial  plexus. 
By  its  upper  border  it  is  in  relation  with  teres  minor,  from  which 
it  is  separated  by  the  scapular  head  of  the  triceps,  and  by  the  loioer' 
it  forms  with  the  latissimus  dorsi  the  lower  and  posterior  border  of 
the  axilla. 

A  large  triangular  space  exists  between  the  two  teres  muscles, 
which  is  divided  into  two  minor  spaces  by  the  long  head  of  the 
triceps. 

Actions. — The  supra-spinatus  raises  the  arm  from  the  side  ;  but 
only  feebly,  from  the  disadvantageous  direction  of  its  force.  The 
infra-spinatus  and  teres  minor  are  rotators  of  the  head  of  the  hume- 
rus outwards.  The  most  important  use  of  these  three  muscles  is  the 
protection  of  the  joint,  and  defence  against  displacement  of  the  head 
of  the  humerus,  in  which  action  they  co-operate  with  the  subscapu- 
laris. The  teres  major  combines,  with  the  latissimus  dorsi,  in  ro- 
tating the  arm  inwards,  and  at  the  same  time  carrying  it  towards 
the  side,  and  somewhat  backwards. 

Acromial  region. 
Deltoid. 

The  convexity  of  the  shoulder  is  formed  by  a  large  triangular 
muscle,  the  deltoid  (A,  delta  ;  zl^og,  resemblance),  which  arises  from 
the  outer  third  of  the  clavicle,  from  the  acromion  process,  and  from 
the  whole  length  of  the  spine  of  the  scapula.  The  fibres  from  this 
broad  origin  converge  to  the  middle  of  the  outer  side  of  the  humerus, 
where  they  are  inserted  into  a  rough  triangular  elevation.  This 
muscle  is  remarkable  for  its  coarse  texture,  and  the  combination  of 
tendinous  and  muscular  fibres.  The  deltoid  muscle  may  now  be 
cut  away  from  its  origin,  and  turned  down,  for  the  purpose  of  bring- 
ing into  view  the  muscles  and  tendons  placed  immediately  around 
the  shoulder  joint.  In  so  doing,  a  large  bursa  will  be  seen  between 
the  under  surface  of  the  muscle  and  the  head  of  the  humerus. 

Relations. — By  its  superficial  surface  with  a  thin  aponeurotic 
fascia,  a  few  fibres  of  the  platysma  myoides,  the  superficial  fascia 
and  integument.  By  its  deep  surface  with  the  shoulder  joint,  from 
which  it  is  separated  by  a  thin  tendinous  fascia,  and  by  a  synovial 
bursa;  with  the  coraco-acromial  ligament,  coracoid  process,  pecto- 
ralis  minor,  coraco-brachialis,  both  heads  of  the  biceps,  tendon  of 


ANTERIOR  HUMERAL  REGION. 


229 


the  pectoralis  major,  tendon  of  the  supra-spinatus,  infra-spinatus, 
teres  minor,  teres  major,  scapular  and  external  head  of  the  triceps, 
the  circumflex  vessels  anterior  and  posterior,  and  humerus.  By  its 
anterior  harder  with  the  external  border  of  the  pectoralis  major, 
from  which  it  is  separated  by  a  cellular  interspace,  lodging  the 
cephalic  vein  and  descending  branch  of  the  thoracico-acromialis 
artery.  Its  'posterior  border  is  thin  above,  where  it  is  connected  with 
the  aponeurotic  covering  of  the  infra-spinatus  muscle,  and  thick  below. 
Actions. — The  deltoid  is  the  elevator  muscle  of  the  arm  in  a  direct 
line,  and  by  means  of  its  extensive  origin  can  carry  the  arm  forwards 
or  backwards  so  as  to  range  with  the  hand  a  considerable  segment 
of  a  large  circle.  The  arm,  raised  by  the  deltoid,  is  a  good  illustra- 
tion of  a  lever  of  the  third  power,  so  common  in  the  animal  machine, 
by  which  velocity  is  gained  at  the  expense  of  power.  In  this  lever, 
the  weight  (hand)  is  at  one  extremity,  the  fulcrum  (the  glenoid  cavity) 
at  the  opposite  end,  and  the  power  (the  insertion  of  the  muscle)  be- 
tween the  two,  but  nearer  to  the  fulcrum  than  to  the  weight. 

Anterior  humeral  region. 
Coraco-brachialis, 
Biceps, 
Brachialis  anticus. 

Dissection. — These  muscles  are  exposed,  on  Fig-  92. 

the  removal  of  the  integument  and  fascia  from 
the  anterior  half  of  the  upper  arm,  and  clearing 
away  the  cellular  tissue. 

The  Cor aco- brachialis,  a  name  composed  of 
its  points  of  origin  and  insertion,  arises  from 
the  coracoid  process  in  common  with  the  short 
head  of  the  biceps  ;  and  is  inserted  into  a  rough 
line  on  the  inner  side  of  the  middle  of  the 
humerus. 

Relations. — By  its  anterior  surface  with  the 
deltoid,  and  pectoralis  major.  By  its  posterior 
surface  with  the  shoulder  joint,  the  humerus, 
subscapulars,  teres  major,  latissimus  dorsi, 
short  head  of  the  triceps,  and  anterior  circum- 
flex vessels.  By  its  internal  border  with  the 
axillary  and  brachial  vessels  and  nerves,  par- 
ticularly with  the  median  and  external  cuta- 
neous nerve,  by  the  latter  of  which  it  is  pierced. 
By  .the  external  border  with  the  short  head  of 
the  biceps  and  brachial  anticus. 

The  Biceps  {bis — xs^aXai',  two  heads)  arises 

Fig.  92.  The  muscles  of  the  anterior  aspect  of  the  upper  arm.  1.  The  coracoid  pro- 
cess of  the  scapula.  2.  The  coraco-chivicular  ligament  (trapezoid),  passing  upwards  to 
the  scapular  end  of  the  clavicle.  3.  The  coraco-acromial  ligament,  passino-  outwards 
to  the  acromion.  4.  The  subscapularis  muscle.  5.  The  teres  major.  6.  The  coraco- 
brachialis.  7.  The  biceps.  8.  The  upper  end  of  the  radius.  9.  The  brachialis  anticus. 
10.  The  internal  head  of  the  triceps. 

20 


230  POSTERIOR  HUMERAL  REGION.  • 

by  two  tendons,  one  the  sJwrt  head,  from  the  coracoid  process  in 
common  with  the  coraco-brachialis  ;  the  other  the  long  head,  from 
the  upper  part  of  the  glenoid  cavity.  The  muscle  is  inserted  by  a 
rounded  tendon,  into  the  tubercle  of  the  radius.  The  long  head,  a 
long  slender  tendon,  passes  through  the  capsular  ligament  of  the 
shoulder  joint  enclosed  in  a  sheath  of  the  synovial  membrane  ;  after 
leaving  the  cavity  of  the  joint,  it  is  lodged  in  the  deep  groove  that 
separates  the  two  tuberosities  of  the  humerus,  the  bicipital  groove. 
A  small  synovial  bursa  is  interposed  between  the  tendon  of  inser- 
tion, and  the  tubercle  of  the  radius.  Jit  the  bend  of  the  elbow,  the 
tendon  of  the  biceps  gives  off  from  its  inner  side  a  broad  tendinous 
band,  which  protects  the  brachial  artery,  and  is  continuous  with  the 
fascia  of  the  fore-arm. 

Relations. — By  its  anterior  surface  with  the  deltoid,  pectoralis 
major,  superficial  and  deep  fascia  and  integument.  By  its  posterior 
surface  the  short  head  rests  upon  the  subscapularis,  from  which  it 
is  separated  by  a  bursa.  In  the  rest  of  its  extent  the  muscle  is  in 
relation  with  the  humerus,  the  teres  major,  latissimus  dorsi,  and 
brachialis  anticus,  from  which  it  is  separated  by  the  external  cuta- 
neous nerve.  By  its  inner  border  with  the  coraco-brachialis, 
brachial  artery  and  veins,  and  median  nerve ;  the  brachial  vessels 
crossing  its  tendon  at  the  bend  of  the  elbow.  By  its  outer  border 
with  the  deltoid  and  supinator  longus. 

The  Brachialis  anticus  is  a  broad  muscle,  covering  the  whole  of 
the  anterior  surface  of  the  lower  part  of  the  humerus  ;  it  arises  by 
two  fleshy  serrations  from  the  depression  on  either  side  of  the  inser- 
tion of  the  deltoid,  and  from  the  anterior  surface  of  the  humerus. 
Its  fibres  converge  to  be  inserted  into  the  coracoid  process  of  the 
ulna. 

Relations. — By  its  anterior  surface  with  the  biceps,  external 
cutaneous  nerve,  brachial  artery  and  veins,  and  median  nerve.  By 
its  posterior  surface  with  the  humerus,  and  anterior  ligament  of  the 
elbow  joint.  By  its  external  border  with  the  supinator  longus,  ex- 
tensor carpi  radialis  longior,  musculo-spiral  nerve,  and  recurrent 
radial  artery.  By  its  internal  border  with  the  intermuscular  aponeu- 
rosis, which  separates  it  from  the  triceps  and  ulnar  nerve,  and  with 
the  pronator  radii  teres. 

Actions. — The  coraco-brachialis  draws  the  humerus  inwards,  and 
assists  in  flexing  it  upon  the  scapula.  The  biceps  and  brachialis 
anticus  are  flexors  of  the  fore-arm,  and  the  former  a  supinator.  The 
brachialis  anticus  is  a  powerful  protection  to  the  elbow-joint. 

Posterior  humeral  region. 

Triceps  extensor  cubiti. 

Dissection. — Remove  the  integument  and  fascia  from  the  posterior 
aspect  of  the  upper  arm. 

The  Triceps  {'t^s'is  xecpaXai,  three   heads,)  arises  by  three  heads. 


POSTERIOR  HUMEKAL  REGION. 


231 


Fig.  93. 


Considered  in  relation  to  their  length,  these  heads  have  been  named 
long,  short,  and  middle ;  and  in  reference  to  their  position,  internal, 
external  and  middle ;  the  term  middle,  in  the  former  case,  referring 
to  the  external  head,  and  in  the  latter  case  to  the  long  head.  This 
has  given  rise  to  much  confusion  and  misunderstanding.  I  shall, 
therefore,  confine  myself  to  the  designations  derived  from  their  rela- 
tions. The  external  head  arises  from  the  humerus  immediately 
below^  the  insertion  of  the  teres  minor.  The  internal  head  (short) 
arises  from  the  humerus  immediately  below  the  insertion  of  the 
teres  major.  The  scapular  head  (long)  lies 
between  the  two  others,  and  arises  from 
the  upper  third  of  the  inferior  border  of 
the  scapula.  The  three  heads  unite  to 
form  a  broad  muscle,  which  is  inserted  by 
an  aponeurotic  tendon  into  the  olecranon 
process  of  the  ulna  ;  a  small  bursa  is  situated 
between  its  tendon  and  the  upper  part  of  the 
olecranon. 

The  scapular  head  of  the  triceps  passes 
between  the  teres  minor  and  major,  and 
divides  the  triangular  space  between  those 
two  muscles  into  two  smaller  spaces,  one  of 
which  is  triangular,  the  other  quadrangular. 
The  triangular  space  is  bounded  by  the  teres 
minor,  teres  major,  and  scapular  head  of  the 
triceps  ;  it  gives  passage  to  the  dorsalis  sca- 
pulae artery  and  veins.  The  quadrangular 
space  is  bounded  on  three  sides  by  the  three 
preceding  muscles,  and  on  the  fourth  by  the 
humerus.  Through  this  space  pass  the  pos- 
terior circumflex  artery  and  veins,  and  cir- 
cumflex nerve. 

Relations. — By  its  posterior  surface  with 
the  deep  and  superficial  fascia  and  integu- 
ment. By  its  anterior  surface  with  the  supe- 
rior profunda  artery,  musculo-spiral  nerve, 

humerus,  intermuscular  aponeurosis,  which  separates  it  from  the 
brachialis  anticus,  and  with  the  elbow  joint.  The  scapular  head  is 
in  relation  posteriorly  with  the  deltoid  and  teres  minor  ;  anteriorly 
with  the  subscapularis,  teres  major,  and  latissimus  dorsi ;  and  ex- 
ternally with  the  posterior  circumflex  vessels  and  nerve. 

Actions. — The  triceps  is  an  extensor  of  the  fore-arm- 


Fig-.  93.  A  posterior  view  of  the  upper  arm,  showing^  the  triceps  muscle.  1.  Its 
external  head.  2.  Its  long-,  or  scapular  head.  3.  Its  internal,  or  short  head.  4.  The 
olecranon  process  of  the  ulna.  5.  The  radius,  6.  The  capsular  ligament  of  the 
shoulder-joint. 


232  ANTERIOR  BRACHIAL  REGION. 

Anterior  brachial  region. 

Superficial  layer. 

Pronator  radii  teres, 
Flexor  carpi  radialis, 
Palmaris  longus, 
Flexor  sublimis  digitorum, 
Flexor  carpi  ulnaris. 

Dissection. — These  muscles  are  seen  by  making  an  incision 
thi'ough  the  integument  along  the  middle  line  of  the  fore-arm,  cross- 
ing each  extremity  by  a  transverse  incision,  and  turning  aside  the 
flaps.     The  superficial  and  deep  fascia  are  then  to  be  removed. 

The  Pronator  radii  teres  arises  by  two  heads ;  one  from  the  inner 
condyle  of  the  humerus,  fascia  of  the  fore-arm  and  intermuscular 
aponeurosis ;  the  other,  from  the  coronoid  process  of  the  ulna ;  the 
median  nerve  passing  between  them.  Its  tendon  is  inserted  into  the 
middle  third  of  the  oblique  ridge  of  the  radius.  The  two  heads  of 
this  muscle  are  best  seen  by  cutting  away  that  which  arises  from 
the  inner  condyle,  and  turning  it  aside.  The  second  head  will  then 
be  seen  with  the  median  nerve  lying  across  it. 

Relations. — By  its  anterior  surface  with  the  fascia  of  the  fore-arm, 
the  supinator  longus,  extensor  carpi  radialis  longior  and  brevior, 
radial  artery  and  veins,  and  radial  nerve.  By  its  posterior  surface 
with  the  brachialis  anticus,  flexor  sublimis  digitorum,  the  ulnar 
artery  and  veins,  and  the  median  nerve  after  it  has  passed  between 
the  two  heads  of  the  muscle.  By  its  upper  border  it  forms  the  inner 
boundary  of  the  triangular  space,  in  which  the  termination  of  the 
brachial  artery  is  situated.  By  its  lower  border  it  is  in  relation  with 
the  flexor  carpi  radialis. 

The  Flexor  carpi  radialis  arises  from  the  inner  condyle  and  the 
sheath  of  fascia  which  surrounds  it.  Its  tendon  passes  through  a 
groove  formed  by  the  scaphoid  bone  and  trapezium,  to  be  inserted 
into  the  base  of  the  metacarpal  bone  of  the  index  finger. 

Relations. — By  its  anterior  surface  with  the  fascia  of  the  fore-arm, 
and  at  the  wrist  with  the  tendinous  canal  through  which  its  tendon 
passes.  By  its  posterior  surface  with  the  flexor  sublimis  digitorum, 
flexor  longus  pollicis,  wrist-joint,  and  groove  in  the  scaphoid  and 
trapezium  bones.  By  its  outer  border  with  the  pronator  radii  teres, 
and  radial  artery  and  veins.  By  its  inner  border  with  the  palmaris 
longus.  The  tendon  is  surrounded  by  a  synovial  membrane  where 
it  plays  through  the  tendinous  canal  of  the  wrist. 

The  Palmaris  longus  muscle  arises  from  the  inner  condyle,  and 
from  the  sheath  of  fascia  which  surrounds  it.  It  is  inserted  into  the 
palmar  fascia.     Occasionally  this  muscle  is  wanting. 

Relations. — By  its  anterior  surface  with  the  fascia  of  the  fore-arm. 
By  the  posterior  surface  with  the  flexor  sublimis  digitorum  ;  to  the 
exlQrnal  side  by  the  flexor  carpi  radialis;  and  to  the  internal  side , 
by  the  flexor  carpi  ulnaris. 


FLEXOR  SUBLIMIS  DIGITORUM. 


233 


Cut  the  flexor  carpi  radialis  and  palmaris  longus  from  their 
origins,  in  order  to  obtain  a  good  view  of  the  whole  extent  of  origin 
of  the  flexor  subhmis  digitorum. 


Fig.  94. 


Fiff.  95. 


The  Flexor  sublimis  digitorum  (perforatus)  arises  from  the  inner 
condyle,  coronoid  process  of  the  ulna,  and  oblique  line  of  the  radius. 

Fig.  94.  Superficial  layer  of  muscles  of  the  fore-arm.  1.  The  lower  part  of  the  bi- 
ceps, with  its  tendon.  2.  A  part  of  the  brachialis  anticus  seen  beneath  the  biceps.  3. 
A  part  of  the  triceps.  4.  The  pronator  radii  teres.  5.  The  flexor  carpi  radialis.  6. 
The  palmaris  longus.  7.  One  of  the  fasciculi  of  the  flexor  sublimis  digitorum;  the  rest 
of  the  muscle  is  seen  beneath  the  tendons  of  the  palmaris  longus  and  flexor  carpi  radia- 
lis,  8.  The  flexor  carpi  ulnaris.  9.  The  palmar  fascia.  10.  The  palmaris  brevis 
muscle.  11.  The  abductor  pollicis  muscle.  12.  One  portion  of  the  flexor  brevis  polli- 
cis;  the  leading  line  crosses  a  part  of  the  adductor  pollicis.  13.  The  supinator  longus 
muscle.  14.  The  extensor  ossis  metacarpi,  and  extensor  primi  internodii  pollicis, 
curving  around  the  lower  border  of  the  fore-arm. 

Fig.  95.  The  deep  layer  of  muscles  of  the  fore-arm.  1.  The  internal  lateral  ligament 
of  the  elbow -joint.  2.  The  anterior  ligament.  3.  The  orbicular  ligament  of  the  head 
of  the  radius.  4.  The  flexor  profundus  digitorum  muscle.  5.  The  flexor  longus  pol- 
licis. 6.  The  pronator  quadratus.  7.  Tlie  adductor  pollicis  muscle.  8.  The  dorsal 
interosseous  muscle  of  the  middle  finger,  and  palmar  interosseous  of  the  ring-finger. 
9.  The  dorsal  interosseous  muscle  of  the  ring-finger,  and  palmar  interosseous  of  the 
little  finger. 

20* 


234  FLEXOR  PBOFtJNDUS  DIGIT0HU3I. 

The  median  nerve  and  ulnar  artery  pass  between  its  origins.  It 
divides  into  four  tendons,  which  pass  beneath  the  annular  ligament 
into  the  palm  of  the  hand,  and  are  inserted  into  the  base  of  the 
second  phalanges  of  the  fingers,  splitting  at  their  terminations  to 
give  passage  to  the  tendons  of  the  deep  flexors  ;  thence  its  designa- 
tion perforatus. 

Relations. — In  the  fore-arm.  By  its  anterior  surface  with  the 
pronator  radii  teres,  flexor  carpi  radialis,  palmaris  longus,  flexor 
carpi  ulnaris,  and  the  deep  fascia  of  the  fore-arm.  By  its  posterior 
surface  with  the  flexor  profundus  digitorum,  flexor  longus  pollicis, 
ulnar  artery,  veins  and  nerve,  and  median  nerve.  This  muscle 
usually  sends  a  fasciculus  to  the  flexor  longus  pollicis.  In  the  hand: 
its  tendons,  after  passing  beneath  the  annular  ligament,  are  in  rela- 
tion swperficiaUy  with  the  superficial  palmar  arch,  and  palmar  fascia ; 
and  deeply  with  the  tendons  of  the  deep  flexor  and  lumbricales. 

The  Flexor  carpi  ulnaris  arises  by  two  heads,  one  from  the  inner 
condyle,  the  other  from  the  olecranon  and  upper  two-thirds  of  the 
inner  border  of  the  ulna.  Its  tendon  is  inserted  into  the  pisiform 
bone,  and  base  of  the  metacarpal  bone  of  the  little  finger. 

Relations. — By  its  anterior  surface  with  the  fascia  of  the  fore-arm, 
with  which  it  is  closely  united  superiorly.  By  its  posterior  surface 
with  the  flexor  sublimis  digitorum,  flexor  profundus,  pronator  quad-  • 
ratus,  and  ulnar  artery,  veins,  and  nerve.  By  its  radial  border  with 
the  palmaris  longus,  and  in  the  lower  third  of  the  fore-arm  with  the 
ulnar  vessels  and  nerve.  The  ulnar  nerve,  and  the  posterior  ulnar 
recurrent  artery,  pass  between  its  two  heads  of  origin. 

Deep  layer. 

Flexor  profundus  digitorum, 
Flexor  longus  pollicis. 
Pronator  quadratus. 

Dissection. — This  group  is  brought  into  view  by  removing  the 
flexor  sublimis,  and  drawing  aside  the  pronator  radii  teres. 

Flexor  profundus  digitorum  (perforans)  arises  from  the  upper  two- 
thirds  of  the  ulna  and  part  of  the  interosseous  membrane,  and  termi- 
nates in  four  tendons,  which  pass  beneath  the  annular  ligament,  and 
between  the  two  slips  of  the  tendons  of  the  flexor  sublimis  (hence 
its  designation,  perforans),  to  be  inserted  into  the  base  of  the  last 
phalanges.  The  tendon  of  the  index  finger  is  always  distinct  from 
the  rest,  the  other  three  tendons  being  more  or  less  intimately  con- 
nected by  cellular  tissue  and  tendinous  slips. 

Four  little  muscular  fasciculi,  called  lumbricales,  are  connected 
•with  the  tendons  of  this  muscle  in  the  palm.  They  will  be  described 
with  the  muscles  of  the  hand. 

Relations. — In  the  fore-arm.  By  its  anterior  surface  with  the 
flexor  sublimis  digitorum,  flexor  carpi  ulnaris,  median  nerve,  and 
ulnar  artery,  veins,  and  nerve.  By  its  posterior  surface  with  the 
ulna,  the  interosseous  membrane,  the  pronator  quadratus,  and  the 


FLEXOR  LONGUS  POLLICIS PRONATOR  QUADKATTJS.  235 

■wrist  joint.  By  its  radial  border  with  the  flexor  longus  pollicis,  the 
anterior  interosseous  artery  and  nerve  being  interposed.  By  its 
ulnar  border  with  the  flexor  carpi  ulnaris.  In  the  hand :  its  tendons 
are  in  relation  superjicial/y  with  the  tendons  of  the  superficial  flexor ; 
and  deeply  with  the  interossei  muscles,  adductor  pollicis,  and  deep 
palmar  arch.  In  the  fingers  :  the  tendons  of  the  deep  flexor  are 
interposed  between  the  tendons  of  the  superficial  flexor  and  the 
phalanges. 

The  Flexor  longus  pollicis  arises  from  the  upper  two-thirds  of  the 
radius,  and  part  of  the  interosseous  membrane.  Its  tendon  passes 
beneath  the  annular  ligament,  to  be  inserted  into  the  base  of  the  last 
phalanx  of  the  thumb. 

Relations. — By  its  anterior  surface  with  the  flexor  subhmis  digito- 
rum,  flexor  carpi  radialis,  supinator  longus,  and  radial  artery  and 
veins.  By  its  posterior  surface  with  the  radius,  interosseous  mem- 
brane, pronator  quadratus  and  wrist  joint.  By  its  ulnar  border  it  is 
separated  from  the  flexor  profundus  digitorum  by  the  anterior  inter- 
osseous artery  and  nerve.  In  the  hand :  after  passing  beneath  the 
annular  ligament,  it  is  lodged  in  the  interspace  between  the  two  por- 
tions of  the  flexor  brevis  pollicis,  and  afterwards  in  the  tendinous 
theca  of  the  phalanges. 

If  the  tendons  of  the  two  last  muscles  be  drawn  aside  or  divided, 
the  third  muscle  of  this  group  will  be  brought  into  view,  lying  across 
the  lower  part  of  the  two  bones. 

The  Pronator  quadratus  arises  from  the  ulna,  and  is  inserted  into 
the  lower  fourth  of  the  oblique  line,  on  the  outer  side  of  the  radius. 
This  muscle  occupies  about  the  lower  fourth  of  the  two  bones,  is 
broad  at  its  origin,  and  narrower  at  its  insertion. 

Relations. — By  its  anterior  surface  with  the  tendons  of  the  supina- 
tor longus,  flexor  carpi  radialis,  flexor  longus  pollicis,  flexor  profun- 
dus digitorum,  and  flexor  carpi  ulnaris,  radial  artery  and  veins,  and 
ulnar  artery,  veins,  and  nerve.  By  its  posterior  surface  with  the 
radius,  ulna,  and  interosseous  membrane. 

Actions. — The  pronator  radii  teres  and  pronator  quadratus  muscles 
rotate  the  radius  upon  the  ulna,  and  render  the  hand  prone.  The 
remaining  muscles  are  flexors:  —  two  flexors  of  the  wrist,  flexor 
carpi  radialis  and  ulnaris ;  two  of  the  fingers,  flexor  sublimis  and 
profundus,  the  former  flexing  the  second  phalanges,  the  latter  the 
last;  one  flexor  of  the  last  phalanx  of  the  thumb,  flexor  longus  pol- 
licis.    The  palmaris  longus  is  a  tensor  of  the  palmar  fascia. 

Posterior  brachial  region. 
Superficial  layer. 
Supinator  longus, 
Extensor  carpi  radialis  longior, 
Extensor  carpi  radialis  brevior, 
Extensor  communis  digitorum, 
Extensor  minimi  digiti. 
Extensor  carpi  ulnaris, 
Anconeus. 


236  POSTERIOR  BRACHIAL  REGION. 

Dissection. — The  integument  is  to  be  divided  and  turned  aside, 
and  the  fasciffi  removed  in  the  same  manner  as  for  the  anterior  bra- 
chial region. 

-  The  Supinator  longus  muscle  is  placed  along  the  radial  border  of 
the  fore-arm.  It  arises  from  the  external  condyloid  ridge  of  the 
humerus,  nearly  as  high  as  the  insertion  of  the  deltoid,  and  is  inserted 
into  the  base  of  the  styloid  process  of  the  radius. 

Relations. — By  its  superficial  surface  with  the  extensor  ossis  me- 
tacarpi  poHicis,  extensor  primi  internodii  pollicis,  and  fascia  of  the 
fore-arm.  By  its  deep  surface  with  the  brachialis  anticus,  extensor 
carpi  radialis  longior,  tendon  of  the  biceps,  supinator  brevis,  prona- 
tor radii  teres,  flexor  carpi  radialis,  flexor  sublimis  digitorum,  flexor 
longus  pollicis,  pronator  quadratus,  radius,  musculo-spiral  nerve, 
radial  and  posterior  interosseous  nerve,  and  radial  artery  and  veins. 
This  muscle  must  be  divided  through  the  middle,  and  the  two 
ends  turned  to  either  side  to  expose  the  next  muscle. 

The  Extensor  carpi  radialis  longior  arises  from  the  external 
condyloid  ridge  below  the  preceding.  Its  tendon  passes  through 
a  groove  in  the  radius,  immediately  behind  the  styloid  process, 
to  be  inserted  into  the  base  of  the  metacarpal  bone  of  the  index 
finger. 

Relations. — By  its  superficial  surface  with  the  supinator  longus, 
extensor  ossis  metacarpi  pollicis,  extensor  primi  internodii  pollicis, 
extensor  secundi  internodii  pollicis,  radial  nerve  and  fascia  of  the 
fore-arm,  and  posterior  annular  ligament.  By  its  deep  surface  with 
the  brachialis  anticus,  extensor  carpi  radialis  brevior,  radius  and 
wrist  joint. 

The  Extensor  carpi  radialis  brevier  is  seen  by  drawing  aside  the 
former  muscle.  It  arises  from  the  external  condyle  of  the  humerus, 
and  is  inserted  into  the  base  of  the  metacarpal  bone  of  the  middle 
finger.  Its  tendon  is  lodged  in  the  same  groove  on  the  radius  with 
the  extensor  carpi  radialis  longior. 

Relations. — By  its  superficial  surface  with  the  extensor  carpi 
radialis  longior,  extensor  ossis  metacarpi  pollicis,  extensor  primi 
internodii  pollicis,  extensor  secundi  internodii  pollicis,  fascia  of  the 
fore-arm,  and  posterior  annular  ligament.  By  its  deep  surface  with 
the  supinator  brevis,  tendon  of  the  pronator  radii  teres,  radius  and 
wrist  joint.  By  its  ulnar  border  with  the  extensor  communis  digi- 
torum. 

The  Extensor  communis  digitorum  arises  from  the  external  con- 
dyle, and  divides  into  four  tendons,  which  are  inserted  into  the  second 
and  third  phalanges  of  the  fingers.  At  the  metacarpo-phalangeal 
articulation  each  tendon  becomes  narrow  and  thick,  and  sends  a 
thin  fasciculus  upon  each  side  of  the  joint.  It  then  spreads  out  and 
receiving  the  tendon  of  the  lumbricalis  forms  a  broad  aponeurosis, 
which  covers  the  whole  of  the  posterior  aspect  of  the  finger.  At 
the  first  phalangeal  joint  the  aponeurosis  divides  into  three  slips. 
The  middle  slip  is  inserted  into  the  base  of  the  second  phalanx,  and 
the  two  lateral  portions  are  continued  onwards  on  each  side  of  the 
joint,  to  be  inserted  into  the  last.   Little  oblique  tendinous  slips  con- 


EXTENSOR  COMMUNIS  DIGITORUM. 


237 


nect  the  tendons  of  the  middle,  ring,  and  little  finger  as  they  cross 
the  back  of  the  hand. 


Fig.  96. 


Fig.  97. 


Relations. — By  its  superficial  surface  with  the  fascia  of  the  fore- 
arm and  back  of  the  hand,  and  with  the  posterior  annular  ligament. 
By  its  deep  surface  with  the  supinator  brevis,  extensor  ossis  meta- 

Fig.  96.  The  superficial  layer  of  muscles  of  the  posterior  aspect  of  the  fore-arm.  1. 
The  lower  part  of  the  biceps.  2,  Part  of  the  brachialis  anticus.  3.  The  lower  part  of 
the  triceps,  inserted  into  the  olecranon.  4.  The  supinator  longus.  .5.  The  extensor 
carpi  radialis  loiigior.  6.  The  extensor  carpi  radialis  brevier.  7.  The  tendons  of  in- 
sertion of  these  two  muscles.  8.  The  extensor  communis  digitorum.  9.  The  extensor 
minimi  digiti.  10.  The  extensor  carpi  ulnaris.  11.  The  anconeus.  12.  Part  of  the 
flexor  carpi  ulnaris.  13.  The  extensor  ossis  metacarpi  and  extensor  primi  internodii 
muscle,  lying  togetiier.  14.  The  extensor  secundi  internodii ;  its  tendon  is  seen  cross- 
ing the  two  tendons  of  the  extensor  carpi  radialis  longior  and  brevier.  15.  The  poste- 
rior annular  ligament.  The  tendons  of  the  common  extensor  are  seen  upon  the  back 
of  the  hand,  and  their  mode  of  distribution  on  the  dorsum  of  the  fingers. 

Fig.  97.  The  deep  layer  of  muscles  on  the  posterior  aspect  of  the  fore-arm.  I.  The 
lower  part  of  the  humerus.  2.  The  olecranon.  3.  The  ulna.  4.  The  anconeus  mus- 
cle. 5.  The  supinator  brevjs  muscle,  fi.  The  extensor  ossis  metacarpi  pollicis.  7. 
The  extensor  primi  internodii  pollicis.  8.  The  extensor  secundi  internodii  pollicis.  9. 
The  extensor  indicis.  10.  The  first  dorsal  interosseous  muscle.  The  other  three  dor- 
sal interossei  are  seen  between  the  metacarpal  bones  of  their  respective  fingers. 


238  POSTERIOR  BRACHIAL  REGION. 

carpi  pollicis,  extensor  primi  internodii,  extensor  secundi  internodii, 
extensor  indicis,  posterior  interosseous  artery  and  nerve,  wrist  joint, 
metacarpal  bones  and  interossei  muscles  and  phalanges.  By  its 
radial  border  with  the  extensor  carpi  radialis  longior  and  brevier. 
By  the  idnar  border  with  the  extensor  minimi  digiti,  and  extensor 
carpi  ulnaris. 

The  Extensor  minimi  digiti  (auricularis)  is  an  off-set  from  the 
extensor  communis,  with  which  it  is  connected  by  means  of  a  ten- 
dinous slip.  Passing  down  to  the  inferior  extremity  of  the  ulna  it 
traverses  a  distinct  fibrous  sheath,  and  at  the  metacarpo-phalangeal 
articulation  unites  with  the  tendon  derived  from  the  long  extensor. 
The  common  tendon  then  spreads  out  into  a  broad  expansion  which 
divides  into  three  slips  to  be  inserted  as  in  the  other  fingers  into  the 
two  last  phalanges.  It  is  to  this  muscle  that  the  little  finger  owes 
its  power  of  separate  extension  ;  and  from  being  called  into  action 
when  the  point  of  the  finger  is  introduced  into  the  meatus  of  the 
ear,  for  the  purpose  of  removing  unpleasant  sensations,  or  producing 
titillation,  the  muscle  was  called  by  the  older  writers  "  auricularis." 

The  Extensor  carpi  ulnaris  arises  from  the  external  condyle  and 
from  the  upper  two-thirds  of  the  border  of  the  ulna.  Its  tendon 
passes  through  the  posterior  groove  in  the  lower  extremity  of  the 
ulna  to  be  inserted  into  the  base  of  the  metacarpal  bone  of  the  little 
finger. 

Relations. — By  its  superficial  surface  with  the  fascia  of  the  fore- 
arm, and  posterior  annular  ligament.  By  its  deep  surface  with  the 
supinator  brevis,  extensor  ossis  metacarpi  pollicis,  extensor  secundi 
internodii,  extensor  indicis,  ulna  and  wrist  joint.  By  its  radial  bor- 
der it  is  in  relation  with  the  extensor  communis  digitorum,  and 
extensor  minimi  digiti,  and  by  the  ulnar  border  with  the  anconeus. 

The  Anconeus  appears  to  be  the  continuation  of  the  triceps ;  it 
arises  from  the  outer  condyle,  and  is  inserted  into  the  olecranon  and 
triangular  surface  on  the  upper  extremity  of  the  ulna. 

Relations. — By  its  superficial  surface  with  a  strong  tendinous  apo- 
neurosis derived  from  the  triceps.  By  its  deep  surface  with  the  elbow 
joint,  orbicular  ligament,  and  slightly  with  the  supinator  brevis. 

Deep  layer. 

Supinator  brevis. 
Extensor  ossis  metacarpi  pollicis, 
Extensor  primi  internodii  pollicis, 
Extensor  secundi  internodii  pollicis, 
Extensor  indicis. 

Dissection. — The  muscles  of  the  superficial  layer  should  be  re- 
moved, in  order  to  bring  the  deep  group  completely  into  view. 

The  Supinator  brevis  cannot  be  seen  in  its  entire  extent,  until  the 
radial  extensors  of  the  carpus  are  divided  from  their  origin.  It 
arises  from  the  external  condyle,  from  the  external  lateral  and  orbi- 
cular ligament,  and  from  the  ulna,  and  winds  around  the  upper  part 


EXTENSOR  MUSCLES.  239 

of  the  radius,  to  be  inserted  into  the  upper  third  of  its  oblique  line. 
The  posterior  interosseous  artery  and  nerve  are  seen  perforating 
the  lower  border  of  this  muscle. 

Relations.— By  its  superficial  surface  with  the  pronator  radii 
teres,  supinator  longus,  extensor  carpi  radialis  longior  and  brevier, 
extensor  communis  digitorum,  extensor  carpi  ulnaris,  anconeus, 
the  radial  artery  and  veins,  the  musculo-spiral  nerve,  radial,  and 
posterior  interosseous  nerve.  By  its  deep  surface  with  the  elbow 
joint  and  its  ligaments,  the  interosseous  membrane,  and  the  radius. 

The  Extensor  ossis  metacarpi  poinds  is  placed  immediately  below 
the  supinator  brevis.  It  arises  from  the  ulna,  interosseous  mem- 
brane, and  radius,  and  is  inserted,  as  its  name  implies,  into  the  base 
of  the  metacarpal  bone  of  the  thumb.  Its  tendon  passes  through  the 
groove  immediately  in  front  of  the  styloid  process  of  the  radius. 

Relations. — By  its  superficial  surface  with  the  extensor  carpi 
ulnaris,  extensor  minimi  digiti,  extensor  communis  digitorum,  fascia 
of  the  fore-arm,  and  annular  ligament.  By  its  deep  surface  with 
the  ulna,  interosseous  membrane,  radius,  tendons  of  the  extensor 
carpi  radialis  longior  and  brevier,  and  supinator  longus,  and  at  the 
wrist  with  the  radial  artery.  By  its  upper  border  with  the  edge  of 
the  supinator  brevis.  By  its  lower  border  with  the  extensor  secundi 
and  primi  internodii.  The  muscle  is  crossed  by  branches  of  the 
posterior  interosseous  artery  and  nerve. 

The  Extensor  primi  internodii  pollicis,  the  smallest  of  the  muscles 
in  this  layer,  arises  from  the  interosseous  membrane  and  radius, 
and  passes  through  the  same  groove  with  the  extensor  ossis  meta- 
carpi, to  be  inserted  into  the  base  of  the  first  phalanx  of  the  thumb. 

Relations. — The  same  as  those  of  the  preceding  muscle  with  the 
exception  of  the  extensor  carpi  ulnaris.  The  muscle  accompanies 
the  extensor  ossis  metacarpi. 

The  Extensor  secundi  internodii  pollicis  arises  from  the  ulna  and 
interosseous  membrane.  Its  tendon  passes  through  a  distinct  canal 
in  the  annular  ligament,  and  is  inserted  into  the  base  of  the  last 
phalanx  of  the  thumb. 

Relations. — By  its  external  surface  with  the  same  relations  as 
the  extensor  ossis  metacarpi.  By  its  deep  surface  with  the  ulna, 
interosseous  membrane,  radius,  wrist  joint,  radial  artery,  and 
metacarpal  bone  of  the  thumb.  The  muscle  is  placed  between  the 
extensor  primi  internodii  and  extensor  indicis. 

The  Extensor  indicis  arises  from  the  ulna  as  high  up  as  the 
extensor  ossis  metacarpi  pollicis,  and  from  the  interosseous  mem- 
brane. Its  tendon  passes  through  a  distinct  groove  in  the  radius, 
and  is  inserted  into  the  aponeurosis  formed  by  the  common  extensor 
tendon  of  the  index  finger. 

Relations. — The  same  as  those  of  the  preceding  muscle,  with  the 
exception  of  the  hand,  where  the  tendon  rests  upon  the  metacarpal 
bone  of  the  fore-finger  and  interosseous  muscle,  and  has  no  relation 
with  the  radial  artery. 

The  tendons  of  the  extensors,  as  of  the  flexor  muscles  of  the 


240  MUSCLES  OF  THE  HAND. 

fore-arm,  are  provided  with  synovial  bursas  as  they  pass  beneath 
the  annular  ligannents :  those  of  the  back  of  the  wrist  have  distinct 
sheaths,  formed  by  the  posterior  annular  ligament. 

Actions. — The  anconeus  is  associated  in  its  action  with  the  triceps 
extensor  cubiti:  it  assists  in  extending  the  fore-arm  upon  the  arm. 
The  supinator  longus  and  brevis  effect  the  supination  of  the  fore- 
arm, and  antagonize  the  two  pronators.  The  extensor  carpi  radialis 
longior  and  brevior,  and  ulnaris,  extend  the  wrist  in  opposition  to 
the  two  flexors  of  the  carpus.  The  extensor  communis  digitorum 
restores  the  fingers  to  the  straight  position,  after  being  flexed  by 
the  two  flexors,  sublimis  and  profundus.  The  extensor  ossis  meta- 
carpi,  primi  internodii,  and  secundi  internodii  poUicis,  are  the 
especial  extensors  of  the  thumb,  and  serve  to  balance  the  actions  of 
the  flexor  ossis  metacarpi,  flexor  brevis,  and  flexor  longus  pollicis. 
The  extensor  indicis  gives  the  character  of  extension  to  the  index 
finger,  and  is  hence  named  "indicator,"  and  the  extensor  minimi 
digiti  supplies  that  finger  with  the  power  of  exercising  a  distinct 
extension. 

MUSCLES    OF    THE    HAND. 

Radial  region. 

Abductor  pollicis, 
Flexor  ossis  metacarpi  (opponens), 
Flexor  brevis  pollicis, 
Adductor  pollicis. 

Dissection. — The  hand  is  best  dissected  by  making  an  incision 
along  the  middle  of  the  palm,  from  the  wrist  to  the  base  of  the 
fingers,  and  crossing  it  at  each  extremity  by  a  transverse  incision, 
then  turning  aside  the  flaps  of  integument.  For  exposing  the 
muscles  of  the  radial  region,  the  removal  of  the  integument  and 
fascia  on  the  radial  side  will  be  sufficient. 

The  Abductor  pollicis  arises  from  the  scaphoid  bone  and  annular 
ligament.     It  is  inserted  into  the  base  of  the  first  phalanx. 

Relations. — By  its  superficial  surface  with  the  external  portion  of 
the  palmar  fascia.  By  its  deep  surface  with  the  flexor  ossis  meta- 
carpi. On  its  inner  side  it  is  separated  by  a  narrow  cellular  inter- 
space from  the  flexor  brevis  pollicis. 

This  muscle  must  be  divided  from  its  origin  and  turned  upwards, 
in  order  to  see  the  next. 

The  Flexor  ossis  metacarpi  (opponens),  arises  from  the  trapezium 
and  annular  ligament,  and  is  inserted  into  the  whole  length  of  the 
metacarpal  bone. 

Relations. — By  its  superficial  surface  with  the  abductor  pollicis. 
By  its  deep  surface  with  the  trapezio-metacarpal  articulation  and 
with  the  metacarpal  bone.    Internally,  with  the  flexor  brevis  pollicis. 

The  flexor  ossis  metacarpi  may  now  be  divided  from  its  origin 
and  turned  aside,  in  order  to  show  the  next  muscle. 


ULNAR  REGION. 


241 


Tig.  98. 


The  Flexor  brevis  pollicis  consists  of  two  portions,  between  which 
lies  the  tendon  of  the  flexor  longus  pollicis.  The  external  portion 
arises  from  the  trapezium  and  an- 
nular ligament ;  the  internal  portion 
from  the  trapezoides  and  os  mag- 
num. They  are  both  inserted  into 
the  base  of  the  first  phalanx  of  the 
thumb,  having  a  sesamoid  bone  in 
each  of  their  tendons  to  protect  the 
joint. 

Relations. — By  its  superficial  sur- 
face with  the  external  portion  of  the 
palmar  fascia.  By  its  deep  surface 
with  the  adductor  pollicis,  tendon 
of  the  flexor  carpi  radialis,  and  tra- 
pezio-metacarpal  articulation.  By 
its  external  surface  with  the  flexor 
ossis  metacarpi  and  metacarpal 
bone.  By  its  inner  surface  with  the 
tendons  of  the  long  flexor  muscles 
and  first  lumbricalis. 

The  Jdductor  pollicis  is  a  triangu- 
lar muscle  ;  it  arises  from  the  whole 
length  of  the  metacarpal  bone  of  the 

middle  finger;  the  fibres  converge  to  its  insertion  into  the  base  of 
the  first  phalanx. 

Relations. — By  its  anterior  surface  with  the' flexor  brevis  pollicis, 
tendons  of  the  deep  flexor  of  "the  fingers,  lumbricales,  and  deep 
palmar  arch.  By  its  posterior  surface  with  the  metacarpal  bones  of 
the  index  and  middle  fingers,  the  interossei  of  the  second  interosseous 
space,  and  the  abductor  indicis. 

Ulnar  region. 

Palmaris  brevis. 
Abductor  minimi  digiti. 
Flexor  brevis  minimi  digiti. 
Flexor  ossis  metacarpi  (adductor). 

Dissection. — Turn  aside  the  ulnar  flap  of  integument  in  the  palm 

Figf.  98.  Tlie  muscles  of  the  hand.  1.  The  annular  ligament.  2,  2.  The  origin  and 
insertion  of  the  abductor  pollicis  muscle;  the  middle  portion  has  been  removed.  3.  The 
flexor  ossis  metacarpi,  or  opponens  pollicis.  4.  One  portion  of  the  flexor  brevis 
pollicis.  5.  The  deep  portion  of  the  flexor  brevis  pollicis.  6.  The  adductor  pollicis. 
7,  7.  The  lumbricales  muscles,  arising  from  the  deep  flexor  tendons,  upon  which  the 
numbers  are  placed.  The  tendons  of  the  flexor  sublimis  have  been  removed  from  the 
palm  of  the  hand.  8.  One  of  the  tendons  of  the  deep  flexor,  passing  between  the  two 
terminal  slips  of  the  tendon  of  the  flexor  sublimis  to  reach  the  last  phalanx.  9.  The 
tendon  of  the  flexor  longus  pollicis,  passing  between  the  two  portions  of  the  flexor 
brevis  to  the  last  phalanx.  10,  The  abductor  minimi  digiti.  11.  The  flexor  brevis 
minimi  digiti.  The  edge  of  the  flexor  ossis  metacarpi.  or  adductor  minimi  digiti,  is 
seen  projecting  beyond  the  inner  border  of  the  flexor  brevis.  12.  The  prominence  of 
the  pisiform  bone.     13.  The  first  dorsal  interosseous  muscle. 

21 


242  MUSCLES  OF  THE  HAND. 

of  the  hand ;  in  doing  this,  a  small  subcutaneous  muscle,  the  palmaris 
brevis,  will  be  exposed.  After  examining  this  muscle,  remove  it 
with  the  deep  fascia,  in  order  to  bring  into  view  the  muscles  of  the 
little  finger. 

The  Palmaris  hrevis  arises  from  the  palmar  fascia,  and  passes 
transversely  inwards,  to  he  inserted  mioi^xe  integument  on  the  inner 
border  of  the  hand. 

Relations. — By  its  superficial  surface  with  the  fat  and  integument 
of  the  ball  of  the  little  finger.  By  its  deep  surface  with  the  internal 
portion  of  the  palmar  fascia,  which  separates  it  from  the  ulnar 
artery,  veins,  and  nerve,  and  from  the  muscles  of  the  inner  border 
of  the  hand. 

The  Abductor  minimi  digiti  arises  from  the  pisiform  bone,  and  is 
inserted  into  the  base  of  the  first  phalanx  of  the  little  finger. 

Relations. — By  its  superficial  surface  with  the  internal  portion  of 
the  deep  fascia  and  the  palmaris  brevis ;  by  its  deep  surface  with 
the  flexor  ossis  metacarpi  and  metacarpal  bone.  By  its  inner  border 
with  the  flexor  brevis  minimi  digiti. 

The  Flexor  brevis  minimi  digiti  arises  from  the  unciform  bone  and 
annular  ligament,  and  is  inserted  into  the  base  of  the  first  phalanx. 
It  is  sometimes  wanting. 

Relations. — By  its  superficial  surface  with  the  internal  portion  of 
the  palmar  fascia,  and  the  palmaris  brevis.  By  its  deep  surface  with 
the  flexor  ossis  metacarpi,  and  metacarpal  bone.  Externally  with 
the  abductor  minimi  digiti,  from  which  it  is  separated  near  its  origin 
by  the  deep  palmar  branch  of  the  ulnar  nerve  and  communicating 
artery.  Internally  with  the  tendons  of  the  flexor  sublimis  and  pro- 
fundus. 

The  Flexor  ossis  metacarpi  (adductor,  opponens)  arises  from  the 
unciform  bone  and  annular  ligament,  and  is  inserted  into  the  whole 
length  of  the  metacarpal  bone  of  the  little  finger. 

Relations. — By  its  superficial  surface  with  the  flexor  brevis  and 
abductor  minimi  digiti.  By  its  deep  surface  with  the  interossei 
muscles  of  the  last  metacarpal  space,  the  metacarpal  bone,  and  the 
flexor  tendons  of  the  little  finger. 

Palmar  region. 

Lumbricales, 
Interossei  palmares, 
Interossei  dorsales. 

The  Lumbricales,  four  in  number,  are  accessories  to  the  deep 
flexor  muscle.  They  arise  from  the  tendons  of  the  deep  flexor ;  the 
first  and  second  from  the  palmar  side,  the  third  from  the  ulnar,  and 
the  fourth  from  the  radial  side;  and  are  zViser/erf  into  the  aponeurotic 
expansion  of  the  extensor  tendons  on  the  radial  side  of  the  fingers. 
The  third,  or  that  of  the  tendon  of  the  ring  finger,  sometimes  bifur- 
cates, or  is  inserted  wholly  into  the  extensor  tendon  of  the  middle 
finsrer. 


INTEROSSEAL  MUSCLES. 


243 


Relations.— In  the  palm  of  the  hand  with  the  flexor  tendons;  at 
their  insertion  with  the  tendons  of  the  interossei  and  metacarpo- 
phalangeal articulations. 

The  palmar  interossei,  three  in  number,  are  placed  upon  the  meta- 
carpal bones,  rather  than  between  them.  They  aiise  from  the  base 
of  the  metacarpal  bone  of  one  finger,  and  are  inserted  into  the  base 
of  the  first  phalanx  and  aponeurotic  expansion  of  the  extensor  tendon 
of  the  same  finger.  The  first  belongs  to  the  index  finger;  the 
second,  to  the  ring  finger ;  and  the  third,  to  the  little  finger ;  the 
middle  finger  being  excluded. 


Fig.  99. 


Tig.  100. 


Relations. — By  their  palmar  surface  with  the  flexor  tendons  and 
with  the  deep  muscles  in  the  palm  of  the  hand.  By  their  dorsal 
surface  with  the  dorsal  interossei.  On  one  side  with  the  metacarpal 
bone,  on  the  other  with  the  corresponding  dorsal  interosseous. 

On  turning  to  the  dorsum  of  the  hand,  the  four  dorsal  interossei 
are  seen  in  the  four  spaces  between  the  metacarpal  bones.  They 
are  bipenniform  muscles,  and  arise  by  two  heads  from  the  adjoining 
sides  of  the  base  of  the  metacarpal  bones.  They  are  inserted  into 
the  base  of  the  first  phalanges,  and  aponeurosis  of  the  extensor 
tendons. 

The  first  is  inserted  into  the  index  finger,  and  from  its  use  is 
called  abductor  indicis  ;  the  second  and  third  are  inserted  into  the 
middle  finger,  compensating  its  exclusion  from  the  palmar  group ; 
the  fourth  is  attached  to  the  ring  finger ;  so  that  each  finger  is  pro- 
vided with  two  interossei,  with  the  exception  of  the  little  finger,  as 
may  be  shown  by  the  adjoining  table : 


Fig.  99.  Palmar  interossei.  1.  Adductor  indicis.  2.  Abductor  annularis.  3.  Interos- 
sens  auricularis. 

Fig-.  100.  Dorsal  interossei.  1.  Abductor  indicis.  2.  Abductor  medii.  3.  Adductor 
medii.    4.  Adductor  annularis. 


244  MUSCLES  OF  THE  LOWER  EXTREJIITY. 

T  J     j:  ^  one  dorsal  (abductor  indicis), 

Index  Tin  O'er  \  -,        ^  " 

■^    °       (  one  palmar. 

Middle  finger,  two  dorsal. 

n-      j:  {  one  dorsal, 

Ring  finger     ^  ,      ' 

&JO         ^  Qijg  palmar. 

Little  finger,  remaining  palmar. 

Relations. — By  their  dorsal  surface  with  a  thin  aponeurosis  which 
separates  them  from  the  tendons  on  the  dorsum  of  the  hand.  By 
their  palmar  surface  with  the  muscles  and  tendons  in  the  palm  of 
the  hand.  By  one  side  with  the  metacarpal  bone ;  by  the  other 
with  the  corresponding  palmar  interosseous.  The  abductor  indicis 
is  in  relation  by  its  palmar  surface,  with  the  adductor  pollicis,  the 
arteria  magna  pollicis  being  interposed.  The  radial  artery  passes 
into  the  palm  of  the  hand  between  the  two  heads  of  the  first  dorsal 
interosseous  muscle  and  the  perforating  branches  of  the  deep 
palmar  arch,  between  the  heads  of  the  other  dorsal  interossei. 

Actions. — The  actions  of  the  muscles  of  the  hand  are  expressed 
in  their  names.  Those  of  the  radial  region  belong  to  the  thumb, 
and  provide  for  three  of  its  movements,  abduction,  adduction,  and 
fiexion.  The  ulnar  group,  in  like  manner,  is  subservient  to  the  same 
motions  of  the  little  finger,  and  the  interossei  are  abductors  and 
adductors  of  the  several  fingers.  The  lumbricales  are  accessory 
in  their  actions  to  the  deep  flexors :  they  were  called  by  the  earlier 
anatomists,^c?zczwn,  i.  e.  fiddlers'  muscles,  from  an  idea  that  they 
might  effect  the  fractional  movements  by  which  the  performer  is 
enabled  to  produce  the  various  notes  on  that  instrument. 

In  relation  to  the  axis  of  the  hand,  the  four  dorsal  interossei  are 
abductors,  and  the  three  palmar,  adductors.  It  will  therefore  be 
seen  that  each  finger  is  provided  with  its  proper  adductor,  and  ab- 
ductor, two  flexors,  and  (with  the  exceptions  of  the  middle  and  ring 
fingers,)  two  extensors.  The  thumb  has  moreover  a  flexor  and  ex- 
tensor, of  the  metacarpal  bone  ;  and  the  little  finger  a  flexor  of  the 
metacarpal  bone  without  an  extensor. 

finjSCLES    OF    THE    LOWER    EXTREMITY. 

The  muscles  of  the  lower  extremity  may  be  arranged  into  groups 
corresponding  with  the  different  regions  of  the  hip,  thigh,  leg,  and 
foot,  as  in  the  following  table : 

HIP. 

Gluteal  region. 
Gluteus  maximus, 
Gluteus  medius. 
Gluteus  minimus, 
Pyriformis, 
Gemellus  superior, 
Obturator  internus, 
Gemellus  inferior, 
Obturator  externus, 
Quadratus  femoris. 


MUSCLES  OF  THE  LOWER  EXTREMITY. 


245 


THIGH. 


Anterior  femoral  region. 

Tensor  vaginae  femoris, 

Sartorius, 

Rectus, 

Vastus  internus, 

Vastus  externus, 

Crureus. 


Internal  femoral  region. 

Iliacus  internus, 
Psoas  magnus, 
Pectineus, 
Adductor  longus, 
Adductor  brevis, 
Adductor  magnus, 
Gracilis. 


Posterior  femoral  region. 

Biceps, 

Semitendinosus, 

Semimembranosus. 


LEG. 


Anterior  tibial  region. 
Tibialis  anticus, 
Extensor  longus  digitorum, 
Peroneus  tertius. 
Extensor  longus  pollicis. 

Fibular  region. 

Peroneus  longus. 
Peroneus  brevis. 


Posterior  tibial  region. 
Superficial  group. 
Gastrocnemius, 
Plantaris, 
Soleus. 

Deep  [posterior']  layer. 

Popliteus, 

Flexor  longus  pollicis, 
Flexor  longus  digitorum. 
Tibialis  posticus. 


FOOT. 


Dorsal  region. 

Extensor  brevis  digitorum, 
Interossei  dorsales. 


Plantar  region. 


First  layer. 

Abductor  pollicis. 
Abductor  minimi  digiti. 
Flexor  brevis  digitorum. 

Second  layer. 

Musculus  accessorius, 
Lumbricales. 


21* 


Third  layer. 

Flexor  brevis  pollicis. 
Adductor  pollicis. 
Flexor  brevis  minimi  digiti, 
Transversus  pedis. 

Fourth  layer. 
Interossei  plantares. 


246  MUSCLES  OF  THE  GLUTEAL  REGION. 

Gluteal  region. 

Gluteus  maximus,  Obturator  internus, 

Gluteus  medius,  Gemellus  inferior, 

"Gluteus  minimus,  Obturator  externus, 

Pyriformis,  Quadratus  fcmoris. 
Gemellus  superior, 

Dissection. — The  subject  being  turned  on  its  face,  and  a  block 
placed  beneath  the  os  pubis  to  support  the  pelvis,  the  student  com- 
mences the  dissection  of  this  region,  by  carrying  an  incision  from 
the  apex  of  the  coccyx  along  the  crest  of  the  ilium  to  its  anterior 
superior  spinous  process ;  or  vice  versa,  if  he  be  on  the  left  side.  He 
then  makes  an  incision  from  the  posterior  fifth  of  the  crest  of  the 
ilium,  to  the  apex  of  the  trochanter  major — this  marks  the  upper 
border  of  the  gluteus  maximus;  and  a  third  incision  from  the 
apex  of  the  coccyx  along  the  fleshy  margin  of  the  lower  border  of 
the  gluteus  maximus,  to  the  outer  side  of  the  thigh,  about  four  inches 
below  the  apex  of  the  trochanter  major.  He  then  reflects  the  in- 
tegument, superficial  fascia,  and  deep  fascia,  which  latter  is  very 
thin  over  this  muscle,  from  the  gluteus  maximus,  following  rigidly 
the  course  of  its  fibres;  and  having  exposed  the  muscle  in  its  entire 
extent,  he  dissects  the  integument  and  superficial  fascia  from  off"  the 
deep  fascia  which  binds  down  the  gluteus  medius,  the  other  portion 
of  this  region. 

The  Gluteus  maximus  (yXovrog,  nates)  is  the  thick,  fleshy  mass  of 
muscle,  of  a  quadrangular  shape,  which  forms  the  convexity  of  the 
nates.  In  structure,  it  is  extremely  coarse,  being  made  up  of  large 
fibres,  which  are  collected  into  fasciculi,  and  these  again  into  dis- 
tinct muscular  masses,  separated  by  deep  cellular  furrows.  It  arises 
from  the  posterior  fifth  of  the  crest  of  the  ilium,  from  the  border  of 
the  sacrum  and  coccyx,  from  the  great  sacro-ischiatic  ligament. 
It  passes  obliquely  outwards  and  downwards,  to  be  inserted  into  the 
rough  line  leading  from  the  trochanter  major  to  the  linea  aspera, 
and  is  continuous  by  means  of  its  tendon  with  the  fascia  lata  cover- 
inoj  the  outer  side  of  the  thigh.  A  larsre  bursa  is  situated  between 
the  broad  tendon  of  this  muscle  and  the  femur. 

Relations. — By  its  superficial  surface  with  a  thin  aponeurotic 
fascia,  which  separates  it  from  the  superficial  fascia  and  integument, 
and  with  the  vastus  externus,  a  bursa  being  interposed.  By  its  deep 
surface  with  the  gluteus  medius,  pyriformis,  gemelli,  obturator  inter- 
nus, quadratus  femoris,  sacro-ischiatic  foramina,  great  sacro-ischiatic 
ligament,  tuberosity  of  the  ischium,  semi-membranosus,  semi-tendi- 
nosus,  biceps,  and  adductor  magnus, ;  the  gluteal  vessels  and  nerves, 
ischiatic  vessels  and  nerves,  and  internal  pudic  vessels  and  nerve. 
By  its  upper  border  it  overlaps  the  gluteus  medius;  and  by  the  lower 
border  forms  the  lower  margin  of  the  nates. 

The  gluteus  maximus  must  be  turned  down  from  its  origin,  in 
order  to  brinsr  the  next  muscles  into  view. 


PYBIF0R3IIS. 


247 


Fig.  101. 


The  Gluteus  medius  is  placed  in  front  of,  rather  than  beneath  the 
gluteus  maximus ;  and  is  covered  in  by  a  process  of  the  deep  fascia, 
which  is  very  thick  and  dense.  It  arises  from  the  outer  lip  of  the 
crest  of  the  ilium  for  four-fifths  of  its  length,  from  the  surface  of  bone 
between  that  border  and  the  superior  curved  line  on  the  dorsum  ilii, 
and  from  the  dense  fascia  above  mentioned.  Its  fibres  converge  to 
the  upper  part  of  the  trochanter  major,  into  which  its  tendon  is 
inse7^ted. 

Relations. — By  its  superficial  surface  with  the  tensor  vaginae  femo- 
ris,  gluteus  maximus,  and  a  very  thick  fascia.  By  its  deep  surface 
with  the  gluteus  minimus,  and  gluteal  vessels  and  nerves.  By  its 
lower  border  with  the  pyriformis  muscle. 

This  muscle  should  now  be  removed  from  its  origin  and  turned 
down,  so  as  to  expose  the  next  which  is  situated  beneath  it. 

The  Gluteus  minimus  is  a  radiated  muscle,  arising  from  the  sur- 
face of  the  dorsum  ilii,  between  the  superior  and  inferior  curved 
lines ;  its  fibres  converge  to  the  anterior  border  of  the  trochanter 
major,  into  which  it  is  inserted  by  means  of  a  rounded  tendon. 
There  is  no  distinct  line  of  separation 
between  the  gluteus  medius  and  mini- 
mus anteriorly. 

Relations. — By  its  superficial  sur- 
face with  the  gluteus  medius,  and 
gluteal  vessels.  By  its  deep  surface 
with  the  surface  of  the  ilium,  the  long 
tendon  of  the  rectus  femoris,  and  the 
capsule  of  the  hip  joint. 

The  Pyriformis  muscle  (pyrum,  a 
pear,  ^.  e.  pear-shaped)  arises  from 
the  anterior  surface  of  the  sacrum, 
by  little  slips  that  are  interposed 
between  the  anterior  sacral  fora- 
mina. It  passes  out  of  the  pelvis, 
through  the  great  sacro-ischiatic  fora- 
men, and  is  inserted  by  a  rounded 
tendon  into  the  trochanteric  fossa  of 
the  femur. 

Relations. — By  its  superficial  or  ex- 
ternal surface  with  the  sacrum  and 
gluteus  maximus.  By  its  deep  or  pel- 
vic surface  with  the  rectum,  the  sacral  plexus  of  nerves,  the  branches 


Fig.  101.  The  deep  muscles  of  the  gluteal  region.  1.  The  external  surface  of  the 
ilium.  2.  The  posterior  surface  of  the  sacrum.  3.  The  posterior  sacro-iliac  ligaments. 
4.  The  tuberosity  of  the  ischium.  5.  The  great  or  posterior  sacro  ischiatic  ligament. 
6.  The  lesser  or  anterior  sacro-ischiatic  ligament.  7.  The  trochanter  major.  8.  The 
gluteus  minimis.  9.  The  p)Triformis.  10.  The  gemellus  superior.  11.  The  obturator 
internus  muscle,  passing  out  of  the  lesser  sacro-ischiatic  foramen.  12.  The  gemellus 
inferior.  13.  The  quadratus  femoris.  14.  The  upper  part  of  tlic  adductor  magnus. 
15.  The  vastus  externus.  16.  The  biceps.  17.  Tlie  gracilis.  18.  The  semi-tendi- 
nosus. 


248  OBTUBATOR  INTERNUS  AND  EXTERNUS. 

of  the  infernal  iliac  artery,  the  great  sacroischiatic  notch,  and 
the  capsule  of  the  hip-joint.  By  its  upper  border  with  the  gluteus 
medius  and  gluteal  vessels  and  nerves.  By  its  lower  border  with  the 
gemellus  superior,  ischiatic  vessels  and  nerves,  and  internal  pudic 
vessels  .and  nerve. 

Immediately  below  the  pyriformis  is  a  small  slip  of  muscle,  the 
gemellus  superior  (gemellus,  double  twin) ;  it  arises  from  the  spine  of 
the  ischium,  and  is  inserted  into  the  upper  border  of  the  tendon  of 
the  obturator  internus,  and  into  the  ti'ochanteric  fossa  of  the  femur. 
The  gemellus  superior  is  not  unfrequently  wanting. 

Relations. — By  its  superficial  surface  with  the  gluteus  maximus, 
the  ischiatic  vessels  and  nerves,  and  internal  pudic  vessels  and  nerve. 
By  its  deep  surface  with  the  pelvis  and  capsule  of  the  hip-joint. 

The  Obturator  internus  arises  from  the  inner  surface  of  the  an- 
terior wall  of  the  pelvis,  being  attached  to  the  margin  of  bone  around 
the  obturator  foramen,  and  to  the  obturator  membrane.  It  passes 
out  of  the  pelvis  through  the  lesser  sacro-ischiatic  foramen,  and  is 
inserted  by  a  flattened  tendon  into  the  trochanteric  fossa  of  the  fe- 
mur. The  lesser  sacro-ischiatic  notch,  over  which  this  muscle 
plays  as  through  a  pulley,  is  faced  with  cartilage,  and  provided  with 
a  synovial  bursa  to  facilitate  its  movements.  The  tendon  of  the 
obturator  is  supported  on  each  side  by  the  two  gemelli  muscles 
(hence  their  names),  which  are  inserted  into  the  sides  of  the  tendon, 
and  appear  to  be  auxiliaries  or  superadded  portions  of  the  obturator 
internus. 

Relations. — By  its  superficial  or  posterior  surface  with  the  internal 
pudic  vessels  and  nerve,  the  obturator  fascia,  which  separates  it 
from  the  levator  ani  and  viscera  of  the  pelvis,  the  sacro-ischiatic 
ligaments,  gluteus  maximus,  and  ischiatic  vessels  and  nerves.  By 
its  deep  or  anterior  surface  with  the  obturator  membrane  and  the 
margin  of  bone  surrounding  it,  the  cartilaginous  pulley  of  the  lesser 
ischiatic  foramen,  the  external  surface  of  the  pelvis,  and  the  capsu- 
lar ligament  of  the  hip  joint.  By  its  upper  border  within  the  pelvis, 
with  the  obturator  vessels  and  nerve ;  external  to  the  pelvis,  with 
the  gemellus  superior.  By  its  lower  border  with  the  gemellus  in- 
ferior. 

The  Gemellus  inferior  arises  from  the  posterior  point  of  the  tube- 
rosity of  the  ischium,  and  is  inserted  into  the  lower  border  of  the 
tendon  of  the  obturator  internus,  and  into  the  trochanteric  fossa  of 
the  femur. 

Relations. — By  its  superficial  surface  with  the  gluteus  maximus, 
and  ischiatic  vessels  and  nerves.  By  its  deep  surface  with  the.  ex- 
ternal surface  of  the  pelvis  and  capsule  of  the  hip  joint.  By  its 
upper  border  with  the  tendon  of  the  obturator  internus.  By  its 
lower  border  with  the  tendon  of  the  obturator  externus  and  quadratus 
femoris. 

In  this  region  the  tendon  only  of  the  obturator  externus  can  be 
seen,  situated  deeply  between  the  gemellus  inferior  and  the  upper 
border  of  the  quadratus  femoris.     To  expose  this  muscle  fully,  it  is 


ANTEKIOR  FEMORAL  REGION.  249 

necessary  to  dissect  it  from  the  anterior  part  of  the  thigh,  after  the 
removal  of  the  pectineus  and  adductor  longus  and  brevis  muscles. 

The  Obturator  ezternus  muscle  (obturare,  to  stop  up)  arises  from 
the  obturator  membrane,  and  from  the  surface  of  bone  immediately 
surrounding  it,  viz.,  from  the  body  and  ramus  of  the  os  pubis  and 
ischium  :  its  tendon  passes  behind  the  neck  of  the  femur,  to  be  in- 
serted with  the  external  rotator  muscles,  into  the  trochanteric  fossa 
of  the  femur.   • 

Relations. — By  its  superficial  or  anterior  surface  with  the  tendon 
of  the  psoas  and  iliacus,  pectineus,  adductor  brevis  and  magnus,  the 
obturator  vessels  and  nerve.  By  its  deep  or  posterior  surface  with 
the  obturator  membrane  and  the  margin  of  bone  which  surrounds 
it,  the  lower  part  of  the  capsule  of  the  hip  joint  and  the  quadratus 
femoris. 

The  Quadratus  femoris  (square-shaped)  arises  from  the  external 
border  of  the  tuberosity  of  the  ischium,  and  is  inserted  into  a  rough 
line  on  the  posterior  border  of  the  trochanter  major,  which  is 
thence  named  linea  quadrati. 

Relations. — By  its  posteriai"  surface  with  the  gluteus  maximus, 
and  ischiatic  vessels  and  nerves.  By  its  anterior  surface  with  the 
tendon  of  the  obturator  externus  and  trochanter  minor ;  a  synovial 
bursa  often  separating  it  from  the  latter.  By  its  upper  border  with 
the  gemellus  inferior ;  and  by  the  lower  border  with  the  adductor 
magnus. 

Actions. — The  glutei  muscles  are  abductors  of  the  thigh,  when 
they  take  their  fixed  point  from  the  pelvis.  Taking  their  fixed  point 
from  the  thigh,  they  steady  the  pelvis  on  the  head  of  the  femur — 
this  action  is  peculiarly  obvious  in  standing  on  one  leg ;  they  assist 
also  in  carrying  the  leg  forward,  in  progression.  The  gluteus 
minimus  being  attached  to  the  anterior  border  of  the  trochanter 
major,  rotates  the  limb  slightly  inwards.  The  gluteus  medius  and 
maximus,  from  their  insertion  into  the  posterior  aspect  of  the  bone, 
rotate  the  limb  outwards ;  the  latter  is,  moreover,  a  tensor  of  the 
fascia  of  the  thigh.  The  other  muscles  rotate  the  limb  outwards, 
everting  the  knee  and  foot ;  hence  they  are  named  external  rotators. 

Anterior  femoral  region. 

Tensor  vaginoe  femoris, 

Sartorius, 

Rectus, 

Vastus  internus, 

Vastus  externus, 

Crureus. 

Dissection. — Make  an  incision  along  the  line  of  Poupart's  liga- 
ment, from  the  anterior  superior  spinous  process  of  the  ilium  to  the 
spine  of  the  os  pubis  ;  and  a  second,  from  the  middle  of  the  pre- 
ceding down  the  inner  side  of  the  thigh,  and  across  the  inner  con- 
dyle of  the  femur,  to  the  head  of  the  tibia,  where  it  may  be  bounded 


250 


SARTOKIUS  MUSCLE. 


Fis.  102. 


by  a  transverse  incision.  Turn  back  the  integument  from  the 
whole  of  this  region,  and  examine  the  superficial  fascia ;  which  is 
next  to  be  removed  in  the  same  manner.  After  the  deep  fascia 
has  been  well  considered,  it  is  likewise  to  be  removed,  by  dissecting 
it  off  in  the  course  of  the  fibres  of  the  muscles.  As  it  might  not 
be  convenient  to  the  junior  student  to  expose  so  large  a  surface  at 
once  as  ordered  in  this  dissection,  the  vertical  incision  may  be 
crossed  by  one  or  two  transverse  incisions,  as  may  be  deemed  most 
proper. 

The  Tensor  vagincB  femoris  (stretcher  of  the  sheath  of  the  thigh) 
is  a  short  flat  muscle,  situated  on  the  outer  side 
of  the  hip.  It  arises  from  the  crest  of  the  ilium, 
near  to  its  anterior  superior  spinous  process, 
and  is  inserted  between  two  layers  of  the  fascia 
lata  at  about  one-fourth  down  the  thigh. 

Relations. — By  its  superficial  surface  with  the 
fascia  lata  and  integument.  By  its  deep  surface 
with  the  internal  layer  of  the  fascia  lata,  gluteus 
medius,  rectus  and  vastus  externus.  By  its 
inner  border,  near  its  origin,  with  the  sartorius. 
The  Sartorius  (tailor's  muscle)  is  a  long 
riband-like  muscle,  arising  from  the  anterior 
superior  spinous  process  of  the  ilium,  and  from 
the  notch  immediately  below  that  process ;  it 
crosses  obliquely  the  upper  third  of  the  thigh, 
descends  behind  the  inner  condyle  of  the  femur, 
and  is  inserted  by  an  aponeurotic  expansion 
into  the  inner  tuberosity  of  the  tibia.  This  ex- 
pansion covers  in  the  insertion  of  the  tendons  of 
the  gracilis  and  semi-tendinosus  muscles.  The 
inner  border  of  the  sartorius  muscle  is  the  guide 
to  the  operation  for  tying  the  femoi'al  artery  in 
the  middle  of  its  course. 

Relations. — By  its  superficial  surface  with  the 
fascia  lata  and  some  cutaneous  nerves.  By  its 
deep  surface  with  the  psoas  and  iliacus,  rectus, 
sheath  of  the  femoral  vessels  and  saphenous 
nerves,  vastus  internus,  adductor  longus,  adduc- 
tor magnus,  gracilis,  long  saphenous  nerve, 
internal  lateral  ligament  of  the  knee  joint.  By  its  expanded  inser- 
tion with  the  tendons  of  the  gracilis  and  semi-tendinosus,  a  synovial 
bursa  being  interposed.  At  the  knee  joint  its  posterior  border  is  in 
relation  with  the  internal  saphenous  vein.    At  the  upper  third  of  the 


Fig.  102.  Tho  muf?clcs  of  the  anterior  femoral  region.  1.  The  crest  of  tlie  ilium. 
2.  Its  anterior  superior  spinous  process.  3.  The  gluteus  medius.  4.  The  tensor 
vaginse  femoris  ;  its  insertion  into  tlie  fascia  lata  is  shown  inferiorly.  5.  Tho  sartorius. 
6.  The  rectus,  7.  The  vastus  externus.  8.  The  vastus  interims,  f).  The  patella. 
10.  The  iliacus  internus.  11.  The  psoas  magnus.  12.  The  pectineus.  13.  The 
adductor  longus.     14.  Part  of  the  adductor  magnus.     15.  The  gracilis. 


RECTDS VASTI  AND  CRUREUS.  251 

thigh  the  sartorius  forms,  wiih  the  lower  border  of  the  adductor 
longus,  an  isosceles  triangle,  whereof  the  base  corresponds  with 
Poupart's  ligament.  A  perpendicular  line,  drawn  from  the  middle 
of  the  base  to  the  apex  of  this  triangle,  immediately  overlies  the 
femoral  artery  with  its  sheath. 

The  Rectus  (straight)  muscle  is  fusiform  in  its  shape  and  bipenni- 
form  in  the  disposition  of  its  fibres.  It  arises  by  two  round  tendons 
— one  from  the  anterior  inferior  spinous  process  of  the  ilium,  the 
other  from  the  upper  lip  of  the  acetabulum.  It  is  inserled  by  a 
broad  and  strong  tendon,  into  the  upper  border  of  the  patella.  It 
is  more  correct  to  consider  the  patella  as  a  sesamoid  bone,  de- 
veloped within  the  tendon  of  the  rectus ;  and  the  ligamentum 
patellae  as  the  continuation  of  the  tendon  to  its  insertion  into  the 
spine  of  the  tibia. 

Relations. — By  its  superficial  surface  with  the  gluteus  medius, 
psoas  and  iliacus,  sartorius ;  and  for  the  lower  three  fourths  of  its 
extent,  with  the  fascia  lata.  By  its  deep  surface  with  the  capsule 
of  the  hip  joint,  the  external  circumflex  vessels,  crureus,  and  vastus 
intern  us  and  externus. 

The  rectus  must  now  be  divided  through  its  middle,  and  the  two 
ends  turned  aside,  to  bring  clearly  into  view  the  next  muscles. 

The  three  next  muscles  are  generally  considered  collectively  under 
the  name  of  triceps  extensor  cruris.  Adopting  this  view,  the  muscle 
surrounds  the  whole  of  the  femur,  excepting  the  I'ough  line  (linea 
aspera)  upon  its  posterior  aspect.  Its  division  into  three  parts  is  not 
well  defined  ;  the  fleshy  mass  upon  each  side  being  distinguished  by 
the  names  of  vastus  internus  and  externus,  the  middle  portion  by 
that  of  crureus. 

The  Vastus  externus,  narrow  below  and  broad  above,  arises  from 
the  outer  border  of  the  patella,  and  is  inserted  into  the  femur  and 
outer  side  of  the  linea  aspera,  as  high  as  the  base  of  the  trochanter 
major. 

Relations. — By  its  superficial  surface  with  the  fascia  lata,  rectus, 
biceps,  semi-membranosus  and  gluteus  maximus,  a  synovial  bursa 
being  interposed.     By  its  deep  surface  with  the  crureus  and  femur. 

The  Vastus  internus,  broad  below  and  narrow  above,  arises  from 
the  inner  border  of  the  patella,  and  is  inserted  into  the  femur  and 
inner  side  of  the  linea  aspera  as  high  up  as  the  anterior  inter-trochan- 
teric  line. 

Relations. — By  its  superficial  surface  with  the  psoas  and  iliacus, 
rectus,  sartorius,  femoral  artery  and  vein  and  saphenous  nerves, 
pectineus,  adductor  longus,  brevis,  and  magnus,  and  fascia  lata.  By 
its  deep  surface  with  the  crureus  and  femur. 

The  Crureus  (crus,  the  leg)  arises  from  the  upper  border  of  the 
patella,  and  is  inserled  into  the  front  aspect  of  the  femur,  as  high  as 
the  anterior  inter-trochanteric  line.  When  the  crureus  is  divided 
from  its  insertion,  a  small  muscular  fasciculus  is  often  seen  upon  the 
lower  part  of  the  femur,  which  is  inserted  into  the  pouch  of  synovial 
membrane  that  extends  upwards  from  the  knee-joint,  behind  the 


252  INTERNAL  FEMORAL  REGION. 

patella.  This  is  named,  from  its  situation,  suh-crureus,  and  would 
seem  to  be  intended  to  support  the  synovial  membrane. 

Relations. — By  its  superficial  surface  with  the  external  circumflex 
vessels,  the  rectus,  and  the  vastus  internus  and  externus.  By  its  deep 
surface  with  the  femur,  the  sub-crureus,  and  synovial  membrane  of 
the  knee  joint. 

Actions. — The  tensor  vaginsB  femoris  renders  the  fascia  lata  tense, 
and  sHghtly  inverts  the  limb.  The  sartorius  flexes  the  leg  upon  the 
thigh,  and,  continuing  to  act,  the  thigh  upon  the  pelvis,  at  the  same 
time  carrying  the  leg  across  that  of  the  opposite  side,  into  the  posi- 
tion in  which  tailors  sit ;  hence  its  name.  Taking  its  fixed  point 
from  below,  it  assists  the  extensor  muscles  in  steadying  the  leg,  for 
the  support  of  the  trunk.  The  other  four  muscles  have  been  collec- 
tively named  quadriceps  extensor,  from  the  similarity  of  action. 
They  extend  the  leg  upon  the  thigh,  and  obtain  a  great  increase  of 
power  by  their  attachment  to  the  patella,  which  acts  as  a  fulcrum. 
Taking  their  fixed  point  from  the  tibia,  they  steady  the  femur  upon 
the  leg  ;  and  the  rectus,  by  being  attached  to  the  pelvis,  serves  to 
balance  the  trunk  upon  the  lower  extremity. 

Internal  femoral  region. 

Iliacus  internus. 
Psoas  magnus, 
Pectineus, 
Adductor  longus, 
Adductor  brevis. 
Adductor  magnus, 
Gracilis. 

Dissection. — These  muscles  are  exposed  by  the  removal  of  the 
inner  flap  of  integument  recommended  in  the  dissection  of  the 
anterior  femoral  region.  The  iliacus  and  psoas  arising  from  within 
the  abdomen  can  only  be  seen  in  their  entire  extent  after  the  removal 
of  the  viscera  from  that  cavity. 

The  Iliacus  internus  is  a  flat  radiated  muscle.  It  arises  from  the 
inner  concave  surface  of  the  ilium;  and,  after  joining  with  the 
tendon  of  the  psoas,  is  inserted  into  the  trochanter  minor  of  the 
femur. 

Relations. — By  its  anterior  surface,  within  the  pelvis,  with  the 
external  cutaneous  nerve,  and  with  the  iliac  fascia,  which  separates 
the  muscle  from  the  peritoneum,  on  the  right  from  the  ccecum,  and 
on  the  left  from  the  sigmoid  flexure  of  the  colon ;  externally  to  the 
pelvis,  with  the  fascia  lata,  rectus,  and  sartorius.  By  its  posterior 
surface  with  the  iliac  fossa,  margin  of  the  pelvis,  and  with  the  cap- 
sule of  the  hip  joint,  a  synovial  bursa  of  large  size  being  interposed, 
which  is  sometimes  continuous  with  the  synovial  membrane  of  the 
articulation.  By  its  inner  border  with  the  psoas  magnus  and  crural 
nerve. 


INTERNAL  FEMORAL  REGION.  253 

The  Psoas  magnus  (4'oa,  lumbus,  a  loin),  situated  by  the  side  of 
the  vertebral  column  in  the  loins,  is  a  long,  fusiform  muscle.  It 
arises  from  the  intervertebral  substances,  part  of  the  bodies  and  bases 
of  the  transverse  processes,  and  from  a  series  of  tendinous  arches, 
thrown  across  the  constricted  portion  of  the  last  dorsal  and  four 
upper  lumbar  vertebras.  These  arches  are  intended  to  protect  the 
lumbar  arteries  and  sympathetic  filaments  of  nerves  from  pressure, 
in  their  passage  beneath  the  muscle.  The  tendon  of  the  psoas 
magnus  unites  with  that  of  the  iliacus,  and  the  conjoined  tendon  is 
inserted  into  the  posterior  part  of  the  trochanter  major,  a  bursa  being 
interposed. 

Relations. — By  its  anterior  surface  with  the  ligamentum  arcuatum 
internum  of  the  diaphragm,  the  kidne}',  the  psoas  parvus,  genito- 
crural  nerve,  sympathetic  nerve,  its  proper  fascia,  the  peritoneum 
and  colon,  and  along  its  pelvic  border  with  the  common  and  external 
iliac  artery  and  vein.  By  its  posterior  surf  ace  with  the  lumbar  ver- 
tebrae, the  lumbar  arteries,  quadratus  lumborum,  from  which  it  is 
separated  by  the  anterior  layer  of  the  aponeurosis  of  the  transver- 
salis,  and  with  the  crural  nerve,  which  near  Poupart's  ligament  gets 
to  its  outer  side.  The  lumbar  plexus  of  nerves  is  situated  in  the 
substance  of  the  posterior  part  of  the  muscle.  In  the  thigh  the 
muscle  is  in  relation  with  the  fascia  lata  in  front;  the  border  of  the 
pelvis  and  hip-joint,  from  which  it  is  separated  by  the  synovial  mem- 
brane, common  to  it  and  the  preceding  muscle,  behind  ;  with  the 
crural  nerve,  and  iliacus  to  the  outer  side ;  and  with  the  femoral 
artery,  by  which  it  is  slightly  overlapped,  to  the  inner  side. 

The  Pectineus  is  a  flat  and  quadrangular  muscle ;  it  arises  from 
the  pectineal  line  (pecten,  a  crest)  of  the  os  pubis,  and  is  inserted 
into  the  line  leading  from  the  anterior  inter-trochanteric  line  to  the 
linea  aspera  of  the  femur. 

Relations. — By  its  anterior  surface  with  the  pubic  portion  of  the 
fascia  lata,  which  separates  it  from  the  femoral  artery  and  vein  and 
internal  saphenous  nerve,  and  lower  down  with  the  profunda  artery. 
By  its  posterior  surface  with  the  capsule  of  the  hip-joint,  and  with 
the  obturator  externus  and  adductor  brevis,  the  obturator  vessels 
being  interposed.  By  its  external  border  with  the  psoas,  the  femoral 
artery  resting  upon  the  line  of  interval.  By  its  internal  border  with 
the  outer  edge  of  the  adductor  longus.  Obturator  hernia  is  situated 
directly  behind  this  muscle,  which  forms  one  of  its  coverings. 

The  Adductor  longus  (adducere,  to  draw  to),  the  most  superficial 
of  the  three  adductors,  arises  by  a  round  and  thick  tendon  from  the 
angle  of  the  os  pubis;  and,  assuming  a  flattened  form,  is  inserted 
into  the  middle  third  of  the  linea  aspera. 

Relations. — By  its  anterior  surface  with  the  pubic  portion  of  the 
fascia  lata,  and  near  its  insertion  with  the  femoral  artery  and  vein. 
By  its  posterior  surface  with  the  adductor  brevis  and  magnus,  the 
anterior  branches  of  the  obturator  vessels  and  nerves,  and  near  its 
insertion  with  the  profunda  artery  and  vein.  By  its  outer  border 
with  the  pectineus,  and  by  the  inner  border  with  the  gracilis. 

22 


254  INTERNAL  FEMORAL  REGION. 

The  pectineus  must  be  divided  near  its  origin  and  turned  out- 
wards, and  the  adductor  longus  through  its  middle  turning  its  ends 
to  either  side,  to  bring  into  view  the  adductor  brevis. 

The  Adductor  brevis,  placed  beneath  the  pectineus  and  adductor 
longus,  is  fleshy,  and  thicker  than  the  adductor  longus;  it  arises 
from  the  body  and  ramus  of  the  os  pubis,  and  is  inserted  into  the 
upper  third  of  the  linea  aspera. 

Relations. — By  its  anterior  surface  with  the  pectineus,  adductor 
longus,  and  anterior  branches  of  the  obturator  vessels  and  nerve. 
By  its  posterior  surface  with  the  adductor  magnus,  and  posterior 
branches  of  the  obturator  vessels  and  nerve.  By  its  outer  border 
with  the  obturator  externus,  and  conjoined  tendon  of  the  psoas  and 
iliacus.  By  its  inner  border  with  the  gracilis  and  adductor  magnus. 
The  adductor  brevis  is  pierced  near  its  insertion  by  the  middle  per- 
forating artery. 

The  adductor  brevis  may  now  be  divided  from  its  origin  and 
turned  outwards,  or  its  inner  two-thirds  may  be  cut  away  entirely, 
when  the  adductor  magnus  muscle  will  be  exposed  in  its  entire 
extent. 

The  Adductor  magnus  is  a  broad  triangular  muscle,  forming  a 
septum  of  division  between  the  muscles  situated  on  the  anterior  and 
those  on  the  posterior  aspect  of  the  thigh.  It  arises  by  fleshy  fibres 
from  the  ramus  and  side  of  the  tuberosity  of  the  ischium ;  and  radiat- 
ing in  its  passage  outwards  is  inserted  into  the  whole  length  of  the 
linea  aspera,  and  inner  condyle  of  the  femur.  The  adductor  magnus 
is  pierced  by  five  openings  ;  the  three  superior,  for  the  three  perfo- 
rating arteries ;  and  the  fourth,  for  the  termination  of  the  profunda. 
The  fifth  is  the  large  oval  opening  in  the  tendinous  portion  of  the 
muscle,  that  gives  passage  to  the  femoral  vessels. 

Relations. — By  its  anterior  surface  with  the  pectineus,  adductor 
brevis,  adductor  longus,  femoral  artery  and  vein,  profunda  artery 
and  vein,  with  their  branches,  and  with  the  posterior  branches  of 
the  obturator  vessels  and  nerve.  By  its  posterior  surface  with  the 
semi-tendinosus,  semi-membranosus,  biceps,  and  gluteus  maximus. 
By  its  inner  border  with  the  gracilis  and  sartorius.  By  its  upper 
border  with  the  obturator  externus,  and  quadratus  femoris. 

The  Gracilis  (slender)  is  situated  along  the  inner  border  of  the 
thigh.  It  arises  by  a  broad  but  very  thin  tendon,  from  the  edge  of 
the  ramus  of  the  os  pubis  and  ischium  ;  and  is  inserted,  by  a  rounded 
tendon  into  the  inner  tuberosity  of  the  tibia,  beneath  the  expansion 
of  the  sartorius. 

Relations. — By  its  inner  or  superficial  surface  with  the  fascia  lata, 
and  below  with  the  sartorius  and  internal  saphenous  nerve ;  the  in- 
ternal saphenous  vein  crosses  it  lying  superficially  to  the  fascia  lata. 
By  its  outer  or  deep  surface  with  the  adductor  longus,  brevis,  and 
magnus,  and  the  internal  lateral  ligament  of  the  knee-joint,  from 
which  it  is  separated  by  a  synovial  bursa  common  to  the  tendons  of 
the  gracilis  and  semi-tendinosus. 

Actions. — The  iliacus,  psoas,  pectineus,  and  adductor  longus  mus- 


POSTEBIOR  FEMORAL  REGION.  255 

cles  bend  the  thigh  upon  the  pelvis,  and,  at  the  same  time,  from  the 
obliquity  of  their  insertion  into  the  lesser  trochanter  and  linea  aspera, 
rotate  the  entire  limb  outwards  ;  the  pectineus  and  adductors  ad- 
duct  the  thigh  powerfully  ;  and,  from  the  manner  of  their  insertion 
into  the  linea  aspera,  they  assist  in  rotating  the  limb  outwards.  The 
graciUs  is  hkewise  an  adductor  of  the  thigh;  but  contributes  also 
to  the  flexion  of  the  leg,  by  its  attachment  to  the  inner  tuberosity  of 
the  tibia. 

Posterior  femoral  region. 

Biceps, 

Semi-tendinosus, 

Semi-membranosus. 

Dissection. — Remove  the  integument  and  fascia  on  the  posterior 
part  of  the  thigh  by  two  flaps,  as  on  the  anterior  region,  and  turn 
aside  the  gluteus  maximus  from  the  upper  part ;  the  muscles  may 
then  be  examined. 

The  Biceps  Jlexor  cruris  (bis,  double,  xscpaXri,  head)  arises  by  two 
heads,  one  by  a  common  tendon  with  the  semi-tendinosus ;  the  other 
muscular,  and  much  shorter,  from  the  lower  two-thirds  of  the 
external  border  of  the  linea  aspera.  This  muscle  forms  the  outer 
hamstring,  and  is  inserted  by  a  strong  tendon  into  the  head  of  the 
fibula. 

Relations. — By  its  superficial  or  posterior  surface  with  the  gluteus 
maximus  and  fascia  lata.  By  its  deep  or  anterior  surface  with  the 
semi-membranosus,  adductor  magnus,  vastus  externus,  the  great 
sciatic  nerve,  popliteal  artery  and  vein,  and  near  its  insertion  with 
the  external  head  of  the  gastrocnemius  and  plantaris.  By  its  i7i7ier 
border  with  the  semi-tendinosus,  and  in  the  popliteal  space  with  the 
popliteal  artery  and  vein. 

The  Semi-tendinosus,  remarkable  for  its  long  tendon,  arises  in 
common  with  the  long  head  of  the  biceps,  from  the  tuberosity  of  the 
ischium.     It  is  inserted  into  the  inner  tuberosity  of  the  tibia. 

Relations. — By  its  superficial  surface  with  the  gluteus  maximus, 
fascia  lata,  and  at  its  insertion  with  the  synovial  bursa  which  sepa- 
rates its  tendon  from  the  expansion  of  the  sartorius.  By  its  deep 
surface  with  the  semi-membranosus,  adductor  magnus,  internal 
head  of  the  gastrocnemius,  and  internal  lateral  ligament  of  the 
knee-joint,  the  synovial  bursa  common  to  it,  and  the  tendon  of  the 
gracilis  being  interposed.  By  its  inner  border  with  the  gracilis  ; 
and  by  its  outer  border  with  the  biceps. 

These  two  muscles  must  be  dissected  from  the  tuberosity  of  the 
ischium,  to  bring  into  view  the  origin  of  the  next. 

The  Semi-membranosus,  remarkable  for  the  tendinous  expansion 
upon  its  anterior  and  posterior  surface,  arises  from  the  tuberosity  of 
the  ischium,  in  front  of  the  common  origin  of  the  two  preceding 
muscles.  It  is  inserted  into  the  posterior  part  of  the  inner  tuberosity 
of  the  tibia ;  at  its  insertion  the  tendon  splits  into  three  portions,  one 


256 


AlfTERIOR  TIBIAL  REGION. 


Fi?.  103. 


of  which  is  inserted  in  a  groove  on  the  inner  side  of  the  head  of 
the  tibia,  beneath  the  internal  lateral  ligament.  The  second  is  con- 
tinuous with  an  aponeuroticexpansionthat  binds  down  the  popliteus 
muscle — the  popliteal  fascia;  and  the  third 
turns  upwards  and  outwards  to  the  external 
condyle  of  the  femur,  forming  the  middle  por- 
tion of  the  posterior  ligament  of  the  knee-joint 
(ligamentum  posticum  Winslowii). 

The  tendons  of  the  two  last  muscles,  viz.  the 
semi-tendinosus  and  semi-membranosus,  with 
those  of  the  gracilis  and  sartorius,  form  the 
inner  hamstring. 

Relations. — By  its  superficial  surface  with  the 
gluteus  maximus,  biceps,  semi-tendinosus,  fascia 
lata,  and  at  its  insertion  with  the  tendinous  ex- 
pansion of  the  sartorius.  By  its  deep  surface 
with  the  quadratus  femoris,  adductor  magnus, 
internal  head  of  the  gastrocnemius,  the  knee- 
joint,  from  which  it  is  separated  by  a  synovial 
membrane,  and  the  popliteal  artery  and  vein. 

By  its  inner  border  with  the  gracilis.  By  its 
outer  border  with  the  great  ischiatic  nerve,  and 
in  the  popliteal  space,  with  the  popliteal  artery 
and  vein. 

If  the  semi-membranosus  muscle  be  turned 
down  from  its  origin,  the  student  will  bring  into 
view  the  broad  and  radiated  expanse  of  the 
adductor  magnus,  upon  which  the  three  flexor 
muscles  above  described  rest. 

Actions. — These  three  hamstring  muscles  are 
the  direct  flexors  of  the  leg  upon  the  thigh  ;  and, 
by  taking  their  origin  from  below,  they  balance 
the  pelvis  on  the  lower  extremities.  The  biceps  from  the  obliquity 
of  its  direction  everts  the  leg  when  partly  flexed,  and  the  semi-ten- 
dinosus turns  the  leg  inwards  when  in  the  same  state  of  flfexion. 


Anterior  tibial  region. 

Tibialis  anticus, 
Extensor  longus  digitorum, 
Peroneus  tertius, 
Extensor  proprius  pollicis. 


Fij^.  103.  The  muscles  of  the  posterior  femoral  and  gluteal  region.  1.  The  gluteus 
medius.  2.  The  gluteus  maximus.  3.  The  vastus  externus  covered  in  by  fiscia  lata. 
4.  The  head  of  the  biceps.  .5.  Its  short  head.  6.  The  semi-tendinosus.  7.  The  semi- 
membranosus. 8.  The  gracilis.  9.  A  part  of  the  inner  border  of  the  adductor  magnus. 
10.  Tiie  edge  of  the  sartorius.  11.  The  popliteal  space.  12.  The  gastrocnemius 
muscle;  its  two  heads.  The  tendon  of  the  biceps  forms  the  outer  hamstring  ;  and  the 
sartorius  with  the  tendons  of  the  gracilis,  semi-tendinosus,  and  semi-membranosus,  the 
inner  hamstring. 


EXTENSOR  PROPRIUS  POLLICIS.  257 

Difsection. — The  dissection  of  the  anterior  tibial  region  is  to  be 
commenced  by  carr3'ing  an  incision  along  the  middle  of  the  leg, 
midway  between  the  tibia  and  the  fibula,  from  the  knee  to  the 
ankle,  and  bounding  it  inferiorlyby  a  transverse  incision,  extending 
from  one  malleolus  to  the  other.  And  to  expose  the  tendons  on 
the  dorsum  of  the  foot,  the  longitudinal  incision  may  be  carried 
onwards  to  the  outer  side  of  the  base  of  the  great  toe,  and  be  ter- 
minated by  another  incision  directed  across  the  heads  of  the  meta- 
tarsal bones. 

The  Tibialis  amicus  muscle  (flexor  tarsi  tibialis)  arises  from  the 
upper  two-thirds  of  the  tibia,  from  the  interosseous  membrane,  and 
from  the  deep  fascia ;  its  tendon  passes  through  a  distinct  sheath  in 
the  annular  ligament,  and  is  inserted  into  the  inner  side  of  the 
internal  cuneiform  bone,  and  base  of  the  metatarsal  bone  of  the 
great  toe. 

Relations. — By  its  anterior  surfdce  with  the  deep  fascia,  from 
"which  many  of  its  superior  fibres  arise,  and  with  the  anterior  annu- 
lar ligament.  By  its  posterior  surface  with  the  interosseous  mem- 
brane, tibia,  ankle-joint,  and  bones  of  the  tarsus  with  their  articu- 
lations. By  its  internal  surface  with  the  tibia.  By  the  external 
surface  with  the  extensor  longus  digitorum,  extensor  proprius  poUicis, 
and  with  the  anterior  tibial  vessels  and  nerve. 

The  Extensor  longus  digitorum  arises  from  the  head  of  the  tibia, 
from  the  upper  three-fourths  of  the  fibula,  from  the  interosseous 
membrane,  and  from  the  deep  fascia.  Below,  it  divides  into  four 
tendons,  which  pass  beneath  the  annular  ligament,  to  be  inserted 
into  the  second  and  third  phalanges  of  the  four  lesser  toes.  The 
mode  of  insertion  of  the  extensor  tendons,  both  in  the  hand  and  in 
the  foot,  is  remarkable ;  each  tendon  spreads  into  a  broad  aponeu- 
rosis over  the  first  phalanx  ;  this  aponeurosis  divides  into  three  slips, 
the  middle  one  is  inserted  into  the  base  of  the  second  phalanx,  and 
the  two  lateral  slips  are  continued  onwards,  to  be  inserted  into  the 
base  of  the  third. 

Relations. — By  its  anterior  surface  with  the  deep  fascia  of  the  leg 
and  foot,  and  with  the  anterior  annular  ligament.  By  its  -posterior 
surface  with  the  interosseous  membrane,  fibula,  ankle-joint,  extensor 
brevis  digitorum,  which  separates  its  tendons  from  the  tarsus,  and 
with  the  metatarsus  and  phalanges.  By  its  inner  surface  with  the 
tibialis  anticus,  extensor  proprius  pollicis,  and  anterior  tibial  vessels. 
By  its  outer  border  with  the  peroneus  longus  and  brevis. 

The  Peroneus  iertius  (flexor  tarsi  fibularis)  arises  from  the  lower 
fourth  of  the  fibula,  and  is  inserted  into  the  base  of  the  metatarsal 
bone  of  the  little  toe.  Although  apparently  but  a  mere  division  or 
continuation  of  the  extensor  longus  digitorum,  this  muscle  may  be 
looked  upon  as  analogous  to  the  flexor  carpi  ulnaris  of  the  fore-arm. 
Sometimes  it  is  altogether  wantino;. 

The  Extensor  proprius  pollicis  lies  between  the  tibialis  anticus 
and  extensor  longus  digitorum.  It  arises  from  the  lower  two-thirds 
of  the  fibula  and  interosseous  membrane.  Its  tendon  passes  through 

22* 


258  POSTERIOR  TIKIAL  REGION. 

a  distinct  sheath  in  the  annular  ligament,  and  is  inserted  into  the 
base  of  the  last  phalanx  of  the  great  toe. 

Relations. — By  its  avLerior  surface  with  the  deep  fascia  of  the  leg 
and  foot,  and  with  the  anterior  annular  ligament.  By  its  'posterior 
surface  with  the  interosseous  membrane,  the  fibula,  the  tibia,  the 
ankle-joint,  the  extensor  brevis  digitorum,  and  the  bones  and  articu- 
lations of  the  great  toe.  It  is  crossed  upon  this  aspect  by  the  ante- 
rior tibial  vessels  and  nerve.  By  its  outer  side  with  the  extensor 
longus  digitorum,  and  in  the  foot  with  the  dorsahs  pedis  artery  and 
veins ;  the  outer  side  of  its  tendon  upon  the  dorsum  of  the  foot  being 
the  guide  to  these  vessels.  By  its  inner  side  with  the  tibialis  anti- 
cus,  and  with  the  anterior  tibial  vessels. 

Actions. — The  tibialis  anticus  and  peroneus  tertius  are  direct  flexors 
of  the  tarsus  upon  the  leg  ;  acting  in  conjunction  with  the  tibialis 
posticus  they  direct  the  foot  inwards,  and  with  the  peroneus  longus 
and  brevis  outwards.  They  assist  also  in  preserving  the  flatness  of 
the  foot  during  progression.  The  extensor  longus  digitorum  and 
extensor  proprius  pollicis,  are  direct  extensors  of  the  phalanges  ;  but 
continuing  their  action,  they  assist  the  tibialis  anticus  and  peroneus 
tertius,  in  flexing  the  entire  foot  upon  the  leg.  Taking  their  origin 
from  below,  they  increase  the  stability  of  the  ankle-joint. 

Posterior  tibial  region. 
Superficial  group. 

Gastrocnemius, 

Plantaris, 

Soleus. 

Dissection. — Make  an  incision  from  the  middle  of  the  popliteal 
space  down  the  middle  of  the  posterior  part  of  the  leg  to  the  heel, 
bounding  it  inferiorly  by  a  transverse  incision  passing  between  the 
two  malleoli.  Turn  aside  the  flaps  of  integument  and  remove  the 
fasciae  from  the  whole  of  this  region ;  the  gastrocnemius  muscle  will 
then  be  exposed. 

The  Gastrocnemius  (yasT^oxv/jixtov,  the  bellied  part  of  the  leg)  arises 
by  two  heads  from  the  two  condyles  of  the  femur,  the  inner  head 
being  the  longest.  They  unite  to  form  the  beautiful  muscle  so  cha- 
racteristic of  this  region  of  the  limb.  It  is  inserted,  by  means  of  the 
tendo  Achillis,  into  the  lower  part  of  the  posterior  tuberosity  of  the 
OS  calcis,  a  synovial  bursa  being  placed  between  that  tendon  and 
the  upper  part  of  the  tuberosity.  The  gastrocnemius  must  be 
removed  from  its  origin,  and  turned  down,  in  order  to  expose  the 
next  muscle. 

Relations. — By  its  superficial  surface  with  the  deep  fascia  of  the 
leg,  which  separates  it  from  the  external  saphenous  vein,  and  with 
the  external  saphenous  nerve.  By  its  deep  surface  with  the  lateral 
portions  of  the  posterior  ligament  of  the  knee-joint,  the  popliteus, 


POSTERIOR  TIBIAL  REGION. 


259 


plantaris,  and  soleus.  The  internal  head  of  the  muscle  rests  against 
the  posterior  surface  of  the  internal  condyle  of  the  femur ;  the  exter- 
nal head  against  the  outer  side  of  the  external  condyle.  In  the  lat- 
ter a  sesamoid  bone  is  sometimes  found. 


Fig.  104. 


Fig.  105. 


The  Plantaris  (planta,  the  sole  of  the  foot),  an  extremely  diminu- 
tive muscle  situated  between  the  gastrocnemius  and  soleus,  arises 
from  the  outer  condyle  of  the  femur;  and  is  inserted,  by  its  long  and 
delicately  slender  tendon,  into  the  inner  side  of  the  posterior  tube- 


Fig.  104.  The  muscles  of  the  anterior  tibial  region.  1.  The  extensor  muscles  inserted 
into  the  patella.  2.  The  subcutaneous  surface  of  the  tibia.  3.  The  tibialis  anticus. 
4.  The  extensor  communis  digitorum.  5.  The  extensor  proprius  pollicis.  6.  The 
peroneus  tertius.  7.  The  peroneus  longus.  8.  The  peroneus  brevis.  9,  9.  The  bor- 
ders of  the  soleus  muscle.  10.  A  part  of  tlie  inner  belly  of  the  gastrocnemius.  11.  The 
extensor  brevis  digitorum  ;  the  tendon  in  front  of  this  number  is  that  of  the  peroneus 
tertius;  and  that  behind  it,  the  tendon  of  the  peroneus  brevis. 

Fig.  105.  The  superficial  muscles  of  the  posterior  aspect  of  the  leg.  1.  The  biceps 
muscle  forming  the  outer  hamstring.  2.  The  tendons  forming  the  inner  hamstring. 
3.  The  popliteal  space.  4.  The  gastrocnemius  muscle.  5,  5.  The  soleus.  6.  The 
tendo  Achillis.  7.  The  posterior  tuberosity  of  the  os  calcis.  8.  The  tendons  of  the 
peroneus  longus  and  brevis  muscles  passing  behind  the  outer  ankle.  9.  The  tendons 
of  the  deep  layer  passing  into  the  foot  behind  the  inner  ankle. 


260  POSTERIOR  TIBIAL  REGION. 

rosityof  the  os  calcis,  by  thesideofthetendo  Achillis;  having  crossed 
obhquely  between  the  two  muscles. 

The  Svleus  (solea,  a  sole)  is  the  broad  muscle  upon  which  the 
plantaris  rests.  It  arises  from  the  head  and  upper  third  of  the  fibula, 
from  the  oblique  line  and  middle  third  of  the  tibia.  Its  fibres  con- 
verge to  the  tendo  Achillis,  by  which  it  is  inserted  into  the  posterior 
tuberosity  of  the  os  calcis.  Between  the  fibular  and  tibial  origins 
of  this  muscle  is  a  tendinous  arch,  beneath  which  the  popliteal  vessels 
and  nerve  pass  into  the  leg. 

Relations. — By  its  superficial  surface  with  the  gastrocnemius  and 
plantaris.  By  its  deep  surface  with  the  intermuscular  fascia,  which 
separates  it  from  the  flexor  longus  digitorum,  tibialis  posticus,  flexor 
longus  pollicis,  from  the  posterior  tibial  vessels  and  nerve,  and  from 
the  peroneal  vessels. 

Actions. — The  three  muscles  of  the  calf  draw  powerfully  on  the 
OS  calcis,  and  lift  the  heel ;  centinuing  their  action,  they  raise  the 
entire  body.  This  action  is  attained  by  means  of  a  lever  of  the 
second  power,  the  fulcrum  (the  toes)  being  at  one  end,  the  weight 
(the  body  supported  on  the  tibia)  in  the  middle,  and  the  power  (these 
muscles)  at  the  other  extremity. 

They  are,  therefore,  the  walking  muscles,  and  perform  all  move- 
ments that  require  the  support  of  the  whole  body  from  the  ground, 
as  dancing,  leaping,  &c.  Taking  their  fixed  point  from  below,  they 
steady  the  leg  upon  the  foot. 

Deep  layer. 

Popliteus, 

Flexor  longus  pollicis, 
Flexor  longus  digitorum. 
Tibialis  posticus. 

Dissection. — After  the  removal  of  the  soleus,  the  deep  layer  will 
be  found  bound  down  by  an  inter-muscular  fascia,  which  is  to  be 
dissected  avi'ay  ;  the  muscles  may  then  be  examined. 

The  Popliteus  muscle  (poples,  the  ham  of  the  leg)  forms  the  floor 
of  the  popliteal  region  at  its  lower  part,  and  is  bound  tightly  down 
by  a  strong  fascia  derived  from  the  middle  slip  of  the  tendon  of  the 
semi-membranosus  muscle.  It  arises  by  a  rounded  tendon  from  a 
deep  groove  on  the  outer  side  of  the  external  condyle  of  the  femur, 
beneath  the  external  lateral  ligament ;  and  spreading  obliquely  over 
the  head  of  the  tibia,  is  inserted  into  the  surface  of  bone  above  its 
oblique  line.  This  line  is  often  called,  from  being  the  limit  of  inser- 
tion of  the  popliteus  muscle,  the  popliteal  line. 

Relations. — By  its  superficial  surface  with  a  thick  fascia  which 
separates  it  from  the  two  heads  of  the  gastrocnemius,  the  plantaris, 
and  the  popliteal  vessels  and  nerve.  By  its  deep  surface  with  the 
articulation  of  the  knee-joint  and  with  the  upper  part  of  the  tibia. 

The  Flexor  longus  pollicis  is  the  most  superficial  of  the  three  next 
muscles.     It  arises  from  the  lower  two-thirds  of  the  fibula,  passes 


TIBIALIS  POSTICUS. 


261 


Fig.  106. 


through  a  groove  in  the  astragalus  and  os  calcis,  which  is  convened 
by  tendinous  fibres  into  a  distinct  sheath  lined  by  a  synovial  mem- 
brane into  the  sole  of  the  foot;  it  is  inserted  into  the  base  of  the  last 
phalanx  of  the  great  toe. 

Relations. — By  its  superficial  surface  with  the  intermuscular 
fascia,  which  separates  it  from  the  soleus  and  tendo  AchiUis.  By 
its  deep  surface  with  the  tibialis  posticus,  fibula,  fibular  vessels, 
interosseous  membrane,  and  ankle-joint.  By  its 
outer  border  with  the  peroneus  longus  and  brevis. 
By  its  inner  border  with  the  flexor  longus  digitorum. 
In  the  foot,  the  tendon  of  the  flexor  longus  pollicis 
is  connected  with  that  of  the  flexor  longus  digi- 
torum by  a  short  tendinous  slip. 

The  Flexor  longus  digitorum  (perforans)  arises 
from  the  surface  of  the  tibia,  immediately  below 
the  popliteal  line.  Its  tendon  passes  through  a 
sheath  common  to  it  and  the  tibialis  posticus  behind 
the  inner  malleolus;  it  then  passes  through  a  second 
sheath  which  is  connected  with  a  groove  in  the 
astragalus  and  os  calcis,  into  the  sole  of  the  foot, 
where  it  divides  into  four  tendons,  which  are  in- 
serted into  the  base  of  the  last  phalanx  of  the  four 
lesser  toes,  perforating  the  tendons  of  the  flexor 
brevis  digitorum. 

Relations. — By  its  superficial  surface  with  the 
intermuscular  fascia,  which  separates  it  from  the 
soleus,  and  with  the  posterior  tibial  vessels  and 
nerve.  By  its  deep  surface  with  the  tibia  and 
tibialis  posticus.  In  the  sale  of  the  foot  its  tendon 
is  in  relation  with  the  abductor  pollicis  and  flexor 
brevis  digitorum,  which  lie  superficially  to  it,  and 
it  crosses  the  tendon  of  the  flexor  longus  pollicis. 
At  the  point  of  crossing  it  receives  the  tendinous 
slip  of  communication  from  the  latter. 

The  flexor  longus  pollicis  must  now  be  removed 
from  its  origin,  and  the  flexor  longus  digitorum  drawn  aside,  to  bring 
into  view  the  entire  extent  of  the  tibialis  posticus. 

The  Tibialis  posticus  (extensor  tarsi  tibialis)  lies  upon  the  interos- 
seous membrane,  between  the  two  bones  of  the  leg.  It  arises  by 
two  heads  from  the  adjacent  sides  of  the  tibia  and   fibula  their 


Y'lg.  106.  The  deep  layer  of  muscles  of  the  posterior  tibial  region.  1.  The  lower 
extremity  of  the  femur.  2.  The  ligamentum  posticum  Winslowii.  3,  The  tendon  of 
the  semimembranosus  muscle  dividing  into  its  three  slips.  4.  The  internal  lateral 
ligament  of  the  knee-joint.  5.  The  external  lateral  ligament.  6.  The  popliteus  muscle. 
7.  The  flexor  longus  digitorum.  8.  The  tibialis  posticus.  9.  The  flexor  longus  pollicis. 
10.  The  peroneus  longus  muscle.  11.  The  peroneus  brevis.  12.  The  tendo  Achillis 
divided  at  its  insertion  into  the  os  calcis.  1.3.  The  tendons  of  the  tibialis  posticus  and 
flexor  longus  digitorum  muscles,  just  as  they  are  about  to  pass  beneath  tlie  internal 
annular  ligament  of  the  ankle  ;  the  interval  between  the  latter  tendon  and  the  tendon 
of  tlie  flexor  longus  pollicis  is  occupied  by  the  posterior  tibial  vessels  and  nerve. 


262  FIBULAR  REGION. 

whole  length,  and  from  the  interosseous  membrane.  Its  tendon 
passes  inwards  beneath  the  tendon  of  the  flexor  longus  digitorum, 
and  runs  in  the  same  sheath ;  it  then  passes  through  a  proper  sheath 
over  the  deltoid  ligament,  and  beneath  the  calcaneo-scaphoid  arti- 
culation, to  be  inserted  into  the  tuberosity  of  the  scaphoid  and 
internal  cuneiform  bone.  While  in  the  common  sheath  behind  the 
internal  malleolus,  the  tendon  of  the  tibialis  posticus  lies  internally 
to  that  of  the  flexor  longus  digitorum,  from  which  it  is  separated 
by  a  thin  fibrous  partition.  A  sesamoid  bone  is  usually  met  with 
in  the  tendon  close  to  its  insertion. 

Relations. — By  its  superficial  surface  with  the  intermuscular 
septum,  the  flexor  longus  pollicis,  flexor  longus  digitorum,  posterior 
tibial  vessels  and  nerve,  peroneal  vessels,  and  in  the  sole  of  the  foot 
with  the  abductor  pollicis.  By  its  deep  surface  with  the  interosseous 
membrane,  the  fibula  and  tibia,  the  ankle  joint,  and  the  astragalus. 
The  anterior  tibial  artery  passes  between  the  two  heads  of  the 
muscle. 

The  student  will  observe  that  the  two  latter  muscles  change  their 
relative  position  to  each  other  in  their  course.  Thus,  in  the  leg,  the 
position  of  the  three  muscles  from  within  outwards,  is — flexor  longus 
digitorum,  tibialis  posticus,  flexor  longus  pollicis.  At  the  inner 
malleolus,  the  relation  of  the  tendon  is — tibialis  posticus,  flexor 
longus  digitorum,  both  in  the  same  sheath;  then  a  broad  groove, 
which  lodges  the  posterior  tibial  artery,  vense  comites,  and  nerve  ; 
and  lastly,  the  flexor  longus  pollicis. 

Actions. — The  poplileus  is  a  flexor  of  the  tibia  upon  the  thigh, 
carrying  it  at  the  same  time  inwards  so  as  to  invert  the  leg.  The 
flexor  longus  pollicis,  and  flexor  longus  digitorum  are  the  long 
flexors  of  the  toes ;  their  tendons  are  connected  in  the  foot  by  a. 
short  tendinous  band,  hence  they  necessarily  act  together.  The 
tibialis  posticus  is  an  extensor  of  the  tarsus  upon  the  leg,  and  an 
antagonist  to  the  tibialis  anticus.  It  combines  with  the  tibialis 
anticus  in  adduction  of  the  foot. 

Fibular  region. 

Peroneus  longus, 
Peroneus  brevis. 

Dissection. — These  muscles  are  exposed  by  continuing  the  dissec- 
tion of  the  anterior  tibial  region  outwards  beyond  the  fibula,  to  the 
border  of  the  posterior  tibial  region. 

The  Peroneus  longus  ("TrsgovT],  fibula,  extensor  tarsi  fibularis  longior) 
muscle  arises  from  the  upper  third  of  the  outer  side  of  the  fibula, 
and  terminates  in  a  long  tendon,  which  passes  behind  the  external 
malleolus,  and  obliquely  across  the  sole  of  the  foot,  through  the 
groove  in  the  cuboid  bone,  to  be  inserted  into  the  base  of  the  meta- 
tarsal bone  of  the  great  toe.  Its  tendon  is  thickened  when  it  glides 
behind  the  external  malleolus,  and  a  sesamoid  bone  is  developed  in 
that  part  which  plays  upon  the  cuboid  bone. 


MUSCLES  OF  THE  FOOT.  263 

Relations. — By  its  superficial  surface  with  the  fascia  of  the  leg 
and  foot.  By  its  deep  surface  with  the  fibula,  peroneus  brevis,  os 
calcis,  and  cuboid  bone,  and  near  the  head  of  the  fibula  with  the 
fibular  nerve.  By  its  anterior  border  it  is  separated  from  the  ex- 
tensor longus  digitorum  by  the  attachment  of  the  fascia  of  the  leg 
to  the  fibula  ;  and  by  the  posterior  border  by  the  same  medium  from 
the  soleus  and  flexor  longus  pollicis.  The  peroneus  longus  is  fur- 
nished with  three  tendinous  sheaths  and  as  many  synovial  mem- 
branes ;  the  first  is  situated  behind  the  external  malleolus,  and  is 
common  to  this  muscle  and  the  peroneus  brevis,  the  second  on  the 
outer  side  of  the  os  calcis,  and  the  third  on  the  cuboid  bone. 

The  Peroneus  brevis  (extensor  tarsi  fibularis  brevier)  lies  beneath 
the  peroneus  longus;  it  arises  from  the  lower  two-thirds  of  the 
fibula,  and  terminates  in  a  tendon  which  passes  behind  the  external 
malleolus  and  through  a  groove  in  the  os  calcis,  to  be  inserted  into 
the  base  of  the  metatarsal  bone  of  the  little  toe. 

Relations. — By  its  superficial  surface  with  the  peroneus  longus 
and  fascia  of  the  leg  and  foot.  By  its  deep  surface  with  the  fibula, 
the  OS  calcis  and  cuboid  bone.  The  lateral  relations  are  the  same 
as  those  of  the  peroneus  longus.  The  tendon  of  the  peroneus  brevis 
has  but  two  tendinous  sheaths  and  two  synovial  membranes ; — one 
behind  the  external  malleolus  and  common  to  both  peronei,  the  other 
upon  the  side  of  the  os  calcis. 

Actions. — The  peronei  muscles  are  extensors  of  the  foot,  con- 
jointly with  the  tibiaUs  posticus.  They  antagonize  the  tibialis  anticus 
and  peroneus  tertius,  which  are  flexors  of  the  foot.  The  v/hole  of 
these  muscles  acting  together,  tend  to  maintain  the  flatness  of  the 
foot  so  necessary  to  security  in  walking. 

FOOT. 

Dorsal  region. 

Extensor  brevis  digitorum, 
Interossei  dorsales. 

The  Extensor  brevis  digitorum  muscle  arises  from  the  outer  side 
of  the  OS  calcis,  crosses  the  foot  obliquely,  and  terminates  in  four 
tendons,  the  innermost  of  which  is  inserted  into  the  base  of  the  first 
phalanx  of  the  great  toe,  and  the  other  three  into  the  sides  of  the 
long  extensor  tendons  of  the  second,  third,  and  fourth  toes. 

Relations. — By  its  upper  surface  with  the  tendons  of  the  extensor 
longus  digitorum,  peroneus  brevis,  and  with  the  deep  fascia  of  the 
foot.  By  its  under  surface  with  the  tarsal  and  metatarsal  bones. 
Its  inner  border  is  in  relation  with  the  dorsalis  pedis  artery,  and  the 
innermost  tendon  of  the  muscle  crosses  that  artery  just  before  its 
division. 

The  Dorsal  interossei  muscles  are  placed  between  the  metatarsal 
bones  ;  they  resemble  the  analogous  muscles  in  the  hand  in  arising 
by  two  heads  from  the  adjacent  sides  of  the  metatarsal  bones  ;  their 


264  MUSCLES  OF  THE  FOOT. 

tendons  are  inserted  into  the  base  of  the  first  phalanx,  and  into  the 
digital  expansion  of  the  tendons  of  the  long  extensor. 

/^he first  dorsalinterosseous  is  inserted  into  the  inner  side  of  the 
second  toe,  and  is  therefore  an  adductor;  the  other  three  areinserled 
into  the  outer  side  of  the  second,  third,  and  fourth  toes,  and  are  con- 
sequently abductors. 

Relations. — By  their  upper  surface  with  a  strong  fascia  which 
separates  them  from  the  extensor  tendons.  By  their  under  surface 
with  the  plantar  interossei.  Each  of  the  muscles  gives  passage  to 
a  small  artery  (posterior  perforating)  which  communicates  with  the 
external  plantar  artery.  And  between  the  heads  of  the  first  interos- 
seous muscle  the  communicating  artery  of  the  dorsalis  pedis  takes 
its  course. 

Plantar  region. 

First  layer. 

Abductor  pollicis, 
•  Abductor  minimi  digiti. 

Flexor  brevis  digitorum. 

Dissection. — The  sole  of  the  foot  is  best  dissected  by  carrying  an 
incision  around  the  heel,  and  along  the  inner  and  outer  borders  of 
the  foot,  to  the  great  and  little  toes.  This  incision  should  divide  the 
integument  and  superficial  fascia,  and  both  together  should  be  dis- 
sected from  the  deep  fascia,  as  far  forward  as  the  base  of  the  pha- 
lano-es,  where  they  may  be  removed  from  the  foot  altogether.  The 
deep  fascia  should  then  be  removed,  and  the  first  layer  of  muscles 
will  be  brought  into  view. 

The  Abductor  pollicis  lies  along  the  inner  border  of  the  foot ;  it 
arises  by  two  heads,  between  which  the  tendons  of  the  long  flexors, 
arteries,  veins,  and  nerves  enter  the  sole  of  the  foot.  One  head 
arises  from  the  inner  tuberosity  of  the  os  calcis,  the  other  from  the 
internal  annular  ligament  and  plantar  fascia.  Insertion,  into  the 
base  of  the  first  phalanx  of  the  great  toe,  and  into  the  internal  sesa- 
moid bone. 

Relations. — By  its  superficial  surface  with  the  internal  portion  of 
the  plantar  fascia.  By  its  deep  surface  with  the  flexor  brevis  pollicis, 
musculus  accessorius,  tendons  of  the  flexor  longus  digitorum  and 
flexor  longus  pollicis,  tendons  of  the  tibialis  anticus  and  posticus, 
the  plantar  vessels  and  nerves  and  the  tarsal  bones.  On  its  outer 
border  with  the  flexor  brevis  digitorum,  from  which  it  is  separated 
by  a  vertical  septum  of  the  plantar  fascia. 

The  Abductor  minimi  digiti  lies  along  the  outer  border  of  the  foot. 
It  arises  from  the  outer  tuberosity  of  the  os  calcis,  and  from  the 
base  of  the  metatarsal  bone  of  the  tittle  toe,  and  is  inserted  into  the 
base  of  the  first  phalanx  of  the  little  toe. 

Relations. — By  its  superficial  surface  with  the  external  portion  of 
the  plantar  fascia.     By  its  deep  surface  with  the  musculus  acces- 


MUSCLES  OF  THE  SOLE  OF  THE  FOOT. 


265 


sorius,  flexor  brevis  minimi  digiti,  with  the  tarsal  bones,  and  with 
the  metatarsal  bone  of  the  little  toe.  By  its  inner  side  with  the 
flexor  brevis  digitorum,  from  which  it  is  separated  by  the  vertical 
septum  of  the  plantar  fascia. 

Fig.  107.  Fig.  108. 


The  Flexor  brevis  digitorum  (perforatus)  is  placed  between  the 
two  preceding  muscles.  It  arises  from  the  under  surface  of  the  os 
calcis  and  plantar  fascia,  and  is  inserted  by  four  tendons  into  the 
base  of  the  second  phalanx  of  the  four  lesser  toes.  Each  tendon 
divides,  previously  to  its  insertion,  to  give  passage  to  the  tendon  of 
the  long  flexor ;  hence  its  cognomen  -perforatus. 

Relations. — By  its  superficial  surface  with  the  plantar  fascia.  By 
its  deep  surface  with  a  thin  layer  of  fascia  which  separates  it  from 
the  musculus  accessorius,  tendons  of  the  flexor  longus  digitorum  and 
flexor  longus  pollicis,  and  plantar  vessels  and  nerves.  By  its  borders 


Fig.  1 07.  The  first  layer  of  muscles  in  the  sole  of  the  foot ;  this  layer  is  exposed  by 
the  removal  of  the  plantar  fascia.  1.  The  os  calcis.  2.  The  posterior  part  of  the  plan- 
tar fascia  divided  transversely.  3.  The  abductor  pollicis.  4.  The  abductor  minimi 
digiti.  5.  The  flexor  brevis  digitorum.  6.  The  tendon  of  the  flexor  longus  pollicis 
muscle.  7,  7.  The  lumbricales.  On  the  second  and  third  toes,  the  tendons  of  the 
flexor  longus  digitorum  are  seen  passing  through  the  bifurcation  of  the  tendons  of  the 
flexor  brevis  digitorum. 

Fig.  108.  The  third  and  a  part  of  the  second  layer  of  muscles  of  the  sole  of  the  foot. 
1.  The  divided  edge  of  the  plantar  fascia,  2.  The  musculus  accessorius.  -3.  The  ten- 
don of  the  flexor  longus  digitorum,  previous  to  its  divii-ion.  4.  The  tendon  of  the 
flexor  longus  pollicis.  5.  The  flexor  brevis  pollicis.  6.  The  adductor  pollicis.  7.  The 
flexor  brevis  minimi  digiti.  8.  Tlie  transversus  pedis.  9.  Interossei  muscles,  plantar 
and  dorsal.  10.  A  convex  ridge  formed  by  the  tendon  of  tiie  peroneus  longus  muscle 
in  its  oblique  course  across  the  foot. 

23 


266 


UUSCLES  OF  THE  SOLE  OF  THE  FOOT. 


Dissection.- 

Fig.  109. 


M'ith  the  vertical  septa  of  the  plantar  fascia,  which  separate  the 
muscle,  en  the  one  side  from  the  abductor  poUicis,  and  on  the  other 
from  the  abductor  minimi  digiti. 

^  Second  layer. 

Musculus  accessorius, 
Lumbricales. 

The  three  preceding  muscles  must  be  divided  from 
their  origin,  and  anteriorly  through  their  ten- 
dons, and  removed,  in  order  to  bring  into  view 
the  second  layer. 

The  Musculus  accessorius  arises  by  two  slips 
from  either  side  of  the  under  surface  of  the  os 
calcis ;  the  inner  slip  being  fleshy,  the  outer  ten- 
dinous. The  muscle  is  inserted  into  the  outer 
side  of  the  tendon  of  the  flexor  longus  digitorum. 

Relations. — By  its  superficial  surface  witb  the 
three  muscles  of  the  superficial  layer,  from  which 
it  is  separated  by  their  fascial  sheaths,  and  with 
the  external  plantar  vessels  and  nerves.  By  its 
deep  surface  with  the  under  surface  of  the  os 
calcis  and  the  long  calcaneo-cuboid  ligament. 

The  Lumbricales  (lumbricus,  an  earthworm) 
are  four  little  muscles  arising  from  the  tibial  side 
of  the  tendons  of  the  flexor  longus  digitorum, 
and  inserted  into  the  expansion  of  the  extensor 
tendons,  and  into  the  base  of  the  first  phalanx  of 
the  four  lesser  toes. 

Relations. — By  their  superficial  surface  with 
the  tendons  of  the  flexor  longus  digitorum.  By 
their  deep  surface  with  the  third  layer  of  muscles  of  the  sole  of  the 
foot.  They  pass  between  the  digital  slips  of  the  deep  fascia  to 
reach  their  insertion. 

Third  layer. 

Flexor  brevis  pollicis, 
Adductor  pollicis. 
Flexor  brevis  minimi  digiti, 
Transversus  pedis. 

Dissection. — The  tendons  of  the  long  flexors  and  the  muscles  con- 
nected with  them  must  be  removed,  to  see  clearly  the  attachments 
of  the  third  layer. 


Fig.  109.  Decp-snatod  mu.=clcs  in  the  sole  of  the  foot.  1.  Tendon  of  the  flexor 
longus  pollicis.  2.  Tendon  of  the  flexor  communis  digitorum  pedis.  3.  Flexor  acces- 
sorius. 4,  4.  Lumbricales.  .5.  Flexor  brevis  digitorum.  6.  Flexor  brevis  pollicis 
pedis.     7.  Flexor  brcvis  minimi  digiti  pedis. 


MVSCLES  OF  THE  SOLE  OF  THE  FOOT.  267 

The  Flexor  hrevis  pollicis  arises  by  a  pointed  tendinous  process 
fronn  the  os  calcis,  the  side  of  the  cuboid,  and  from  the  external  and 
middle  cuneiform  bones  ;  and  is  inserted  by  two  heads  into  the  base 
of  the  first  phalanx  of  the  great  toe.  Two  sesamoid  bones  are  de- 
veloped in  the  tendons  of  insertion  of  these  two  heads,  and  the  tendon 
of  the  flexor  longus  pollicis  lies  in  the  groove  between  them. 

Relations. — By  its  superficial  surface  with  the  abductor  pollicis, 
tendon  of  the  flexor  longus  pollicis,  and  plantar  fascia.  By  its  deep 
surface  with  the  tarsal  bones  and  their  ligaments,  the  metatarsal 
bone  of  the  great  toe,  and  the  insertion  of  the  tendon  of  the  peroneus 
longus.  By  its  inner  border  with  the  abductor  pollicis.  By  its  outer 
border  with  the  adductor  pollicis. 

The  Adductor  pollicis  arises  from  the  cuboid  bone,  from  the  sheath 
of  the  tendon  of  the  peroneus  longus,  and  from  the  base  of  the  third 
and  fourth  metatarsal  bones.  It  is  inserted  into  the  base  of  the  first 
phalanx  of  the  great  toe. 

Relations. — By  its  superficial  surf  ace  with  the  tendons  of  the  flexor 
longus  and  flexor  brevis  digitorum,  the  musculus  accessorius,  and 
lumbricales.  By  its  deep  surface  with  the  tarsal  bones  and  liga- 
ments, the  external  plantar  artery  and  veins,  the  interossei  muscles, 
tendon  of  the  peroneus  longus,  and  metatarsal  bone  of  the  great  toe. 
By  its  inner  border  with  the  flexor  brevis  pollicis. 

The  Flexor  brevis  minimi  digiti  arises  from  the  base  of  the  meta- 
tarsal bone  of  the  little  toe,  and  from  the  sheath  of  the  tendon  of  the 
peroneus  longus.  It  is  inserted  into  the  base  of  the  first  phalanx  of 
the  little  toe. 

Relations. — By  its  superficial  surf  ace  with  the  tendons  of  the  flexor 
longus  and  flexor  brevis  digitorum,  the  fourth  lumbricalis,  abductor 
minimi  digiti,  and  plantar  fascia.  By  its  deep  surface  with  the 
plantar  interosseous  muscle  of  the  fourth  metatarsal  space,  and  the 
metatarsal  bone. 

The  Transversus  pedis  arises  by  fleshy  slips,  from  the  heads  of 
the  metatarsal  bones  of  the  four  lesser  toes.  Its  tendon  is  inserted 
into  the  base  of  the  first  phalanx  of  the  great  toe. 

Relations. — By  its  superficial  surface  with  the  tendons  of  the  flexor 
longus  and  flexor  brevis  digitorum,  and  the  lumbricales.  By  its  deep 
surface  with  the  interossei,  and  heads  of  the  metatarsal  bones. 

Fourth  layer. 
Interossei  plantares. 

The  Plantar  interossei  muscles  are  three  in  number,  and  are 
placed  upon  rather  than  between  the  metatarsal  bones.  They  arise 
from  the  base  of  the  metatarsal  bones  of  the  three  outer  toes,  and 
are  inserted  into  the  inner  side  of  the  extensor  tendon  and  base  of 
the  first  phalanx  of  the  same  toes.  In  their  action  they  are  all 
adductors. 

Relations. — By  their  superficial  surface  with  the  dorsal  interossei 


268 


ACTION  OF  MUSCLES  OF  THE  FOOT. 


and  the  metatarsal  bones.  By  their  deep  surface  with  the  external 
plantar  artery  and  veins  with  their  branches,  the  adductor  pollicis, 
transversus  pedis,  and  flexor  minimi  digiti. 


Fig.  111. 


Actions. — All  the  preceding  muscles  act  upon  the  toes ;  and  the 
movements  which  they  are  capable  of  executing  maybe  referred  to 
four  heads,  viz.  flexion,  extension,  adduction,  and  abduction.  In 
these  actions  they  are  grouped  in  the  following  manner : 


Flexion. 

Flexor  longus  digitorum, 
Flexor  brevis  digitorum. 
Flexor  accessorius. 
Flexor  minimi  digiti. 

Adduction. 

one  dorsal, 


Interossei, 


three  plantar. 


Extension. 

Extensor  longus  digitorum, 
Extensor  brevis  digitorum. 


Abduction. 

Interossei,  three  dorsal, 
Abductor  minimi  digiti. 


The  great  toe,  like  the  thumb  in  the  hand,  enjoys  an  independent 
action,  and  is  provided  with  distinct  muscles  to  perform  its  move- 
Fig.  110.  Dorsal  interossei.     1.  Abductor  secundi,    2.  Adductor  sccundi.     3.  Ad- 
ductor tertii.     4.  Adductor  quarti. 

Fig.  111.  Plantar  interossei.     1.  Abductor  tertii.     2.  Abductor  quarti.    3.  Interos- 
Bcous  minimi  digiti. 


ACTION  OF  MUSCLES  OF  THE  FOOT. 


269 


ments.     These  movements  are  precisely  the  same  as  those  of  the 
other  toes,  viz. : 


Flexion. 

Flexor  longus  poljicis, 
Flexor  brevis  pollicis, 

Adduction. 
Adductor  pollicis. 


Extension. 

Extensor  proprius  pollicis, 
Extensor  brevis  digitorum. 

Abduction. 
Abductor  pollicis. 


The  only  muscles  excluded  from  this  table  are  the  lumbricales, 
four  small  muscles,  which  from  their  attachments  to  the  tendons  of 
the  long  flexor,  appear  to  be  assistants  to  their  action  ;  and  the 
transversus  pedis,  a  small  muscle  placed  transversely  in  the  foot 
across  the  heads  of  the  metatarsal  bones,  which  has  for  its  office 
the  drawing  together  of  the  toes. 


23* 


CHAPTER   IV. 

ON  THE  FASCIA. 

Fascia  (fascia,  a  bandage,)  is  the  name  assigned  to  laminae  of 
various  extent  and  thickness,  which  are  distributed  through  ttie  dif- 
ferent regions  of  the  body,  for  the  purpose  of  investing  or  protecting 
the  softer  and  more  dehcate  organs.  From  a  consideration  of  their 
structure,  these  fasciae  may  be  arranged  in  three  classes : — cellular 
fasciae,  cellulo-fibrcus  fasciae,  and  tendino-fibrous  fascias. 

The  cellular  fascia  is  best  illustrated  in  the  common  subcutaneous 
investment  of  the  entire  body,  the  superficial  fascia.  This  structure 
is  situated  immediately  beneath  the  integument  over  every  part  of 
the  frame,  and  is  the  medium  of  connexion  between  that  layer  and 
the  deeper  parts.  It  is  composed  of  cellular  tissue  containing  in  its 
areolae  a  considerable  abundance  of  adipose  vesicles.  The  fat,  being 
a  bad  conductor  of  caloric,  serves  to  retain  the  warmth  of  the  body, 
while  it  forms  at  the  same  time  a  yielding  tissue,  through  which  the 
minute  vessels  and  nerves  may  pass  to  the  papillary  layer  of  the 
skin,  without  incurring  the  risk  of  obstruction  from  injury  or  pres- 
sure upon  the  surface.  By  dissection,  the  superficial  fascia  may  be 
separated  into  two  layers,  between  which  are  found  the  superficial 
or  cutaneous  vessels  and  nerves ;  as,  the  superficial  epigastric  artery, 
the  saphenous  veins,  the  radial  and  ulnar  veins,  the  superficial  lym- 
phatic vessels,  also  the  cutaneous  muscles,  as  the  platysma  myoides, 
orbicularis  palpebrarum,  sphincter  ani,  &c.  In  some  situations 
where  the  deposition  of  fat  would  have  been  injurious  to  the  func- 
tions of  the  part,  the  cells  of  the  cellular  fascia  are  moistened  by  a 
serous  exhalation,  analogous  to  the  secretion  of  serous  membranes, 
as  in  the  eyelids  and  scrotum. 

The  cellulo-Jibrous  fascia  appears  to  result  from  a  simple  con- 
densation of  cellular  tissue  deprived  of  its  fat,  and  intermingled  with 
strong  fibres  disposed  in  various  directions,  so  as  to  constitute  an 
inelastic  membrane  of  considerable  strength.  Of  this  structure  is 
the  deep  fascia  of  the  neck,  some  of  the  fasciae  of  the  cavities  of  the 
trunk,  as  the  thoracic  and  transversalis  fasciae,  and  the  sheaths  of 
vessels. 

The  tendino-fibrous  fascia  is  the  strongest  of  the  three  kinds  of 
investing  membrane;  it  is  composed  of  strong  tendinous  fibres,  run- 
ning parallel  with  each  other,  and  connected  by  other  fibres  of  the 
same  kind  passing  in  different  directions.  When  freshly  exposed, 
it  is  brilliant  and  nacreous,  and  is  tough,  inelastic,  and  unyielding. 
In  the  limbs  it  forms  the  deep  fascia,  enclosing  and  forming  distinct 


FASCIAE  OF  THE  HEAD  AND  NECK.  271 

sheaths  to  all  the  muscles  and  tendons.  Tt  is  thick  upon  the  outer 
and  least  protected  side  of  the  limb,  and  thinner  upon  its  inner  side. 
It  is  firmly  connected  to  the  bones  and  to  the  prominent  points  of 
each  region,  as  to  the  pelvis,  knee,  and  ankle,  in  the  lower,  and  to 
the  clavicle,  scapula,  elbov^^,  and  wrist  in  the  upper  extremity.  It 
assists  the  muscles  in  their  action,  by  keeping  up  a  tonic  pressure 
on  their  surface ;  aids  materially  in  the  circulation  of  the  fluids  in 
opposition  to  the  laws  of  gravity;  and  in  the  palm  of  the  hand  and 
sole  of  the  foot  is  a  powerful  protection  to  the  structures  which 
enter  into  the  formation  of  these  regions.  In  some  situations  its 
tension  is  regulated  by  muscular  action,  as  by  the  tensor  vaginae 
femoris  and  gluteus  maximus  in  the  thigh,  by  the  biceps  in  the  leg, 
and  by  the  biceps  and  palmaris  longus  in  the  arm  ;  in  other 
situations  it  affords  an  extensive  surface  for  the  origin  of  the  fibres 
of  muscles. 

The  fascia  may  be  arranged  like  the  other  textures  of  the  body 
into — 1.  Those  of  the  head  and  neck.  2.  Those  of  the  trunk.  3. 
Those  of  the  upper  extremity.     4.  Those  of  the  lower  extremity. 

FASCIA   OF   THE    HEAD     AND    NECK. 

The  temporal  fascia  is  a  strong  tendino-fibrous  membrane  which 
covers  in  the  temporal  muscle  at  each  side  of  the  head,  and  gives 
origin  by  its  internal  surface  to  the  superior  muscular  fibres.  It  is 
attached  to  the  whole  extent  of  the  temporal  ridge  above,  and  to 
the  zygomatic  arch  below;  in  the  latter  situation  it  is  thick  and 
divided  into  two  layers,  the  external  being  connected  to  the  upper 
border  of  the  arch,  and  the  internal  to  its  inner  surface.  A  small 
quantity  of  fat  is  usually  found  between  these  two  layers,  together 
with  the  orbital  branch  of  the  temporal  artery. 

The  S2iperjicial  cervical  fascia  contains  between  its  layers  the 
platysma  myoides  muscle. 

The  deep  cervical  fascia  is  a  strong  cellulo-fibrous  layer  which 
invests  the  muscles  of  the  neck,  and  retains  and  supports  the  vessels 
and  nerves.  It  commences  posteriorly  at  the  ligamentum  nuchas, 
and  passes  forwards  at  each  side  beneath  the  trapezius  muscle  to 
the  posterior  border  of  the  sterno-mastoid ;  here  it  divides  into  two 
layers  which  embrace  that  muscle  and  unite  upon  its  anterior  border 
to  be  prolonged  onwards  to  the  middle  line  of  the  neck,  where  it 
becomes  continuous  with  the  fascia  of  the  opposite  side.  Besides 
thus  constituting  a  sheath  for  the  sterno-mastoid,  it  also  forms 
sheaths  for  the  other  muscles  of  the  neck  over  which  it  passes.  If 
the  superficial  layer  of  the  sheath  of  the  sterno-mastoid  be  traced 
upwards,  it  will  be  found  to  pass  over  the  parotid  gland  and  mas- 
seter  muscle,  and  to  be  inserted  into  the  zygomatic  arch  ;  and  if  it 
be  traced  downwards,  it  will  be  seen  to  pass  in  front  of  the  clavicle 
and  become  lost  upon  the  pectoralis  major  muscle.  If  the  deep 
layer  of  the  sheath  be  examined  superiorly,  it  will  be  found  attached 


272 


FASCIA  OF  THE  TRUjVK. 


Fig.  112. 


to  the  styloid  process,  from  which  it  is  reflected  to  the  angle  of  the 

lower  jaw,  forming  the  stylo-maxil- 
lary ligament ;  and  if  it  be  followed 
downwards,  it  will  be  found  con- 
nected with  the  tendon  of  the  omo- 
hyoid muscle,  and  may  thence  be 
traced  behind  the  clavicle  where 
it  encloses  the  subclavius  muscle, 
and  being  extended  from  the  car- 
tilage of  the  first  rib  to  the  cora- 
coid  process,  constitutes  the  costo- 
coracoid  membrane.  In  front  of 
the  sterno-mastoid  muscle,  the  deep 
fascia  is  attached  to  the  border  of 
the  lower  jaw  and  os  hyoides,  and 
forms  a  distinct  sheath  for  the  sub- 
maxillary gland.  Inferiorly  it  di- 
vides into  two  layers,  one  of  which 

passes  in  front  of  the  sternum,  while  the  other  is  attached  to  its 

superior  border. 


FASCIA     OF     THE     TRUNK. 

The  thoracic  fascia*  is  a  dense  layer  of  cellulo-fibrous  membrane 
stretched  horizontally  across  the  superior  opening  of  the  thorax.  It 
is  firmly  attached  to  the  concave  margin  of  the  first  rib,  and  to  the 
inner  surface  of  the  sternum.  In  front  it  leaves  an  opening  for  the 
connexion  of  the  cervical  with  the  thoracic  portion  of  the  thymus 
gland,  and  behind  it  forms  an  arch  across  the  vertebral  column,  to 
give  passage  to  the  oesophagus. 

At  the  point  where  the  great  vessels  and  trachea  pass  through 
the  thoracic  fascia,  it  divides  into  an  ascending  and  descending  layer. 
The  ascending  layer  is  attached  to  the  trachea,  and  becomes  con- 
tinuous with  the  sheath  of  the  carotid  vessels,  and  with  the  deep 


Fig.  112.  A  transverse  section  of  the  neck,  showing  the  deep  cervical  fascia  and  its 
numerous  prolongations,  forming  sheaths  for  the  different  muscles.  As  the  figure  is 
symmetrical,  the  figures  of  reference  are  placed  only  on  one  side.  1.  The  platysma 
myoides.  2.  The  trapezius.  3.  The  ligamcntum  nuchse,  from  which  the  fascia  may 
be  traced  forwards  beneath  the  trapezius,  enclosing  the  other  muscles  of  the  neck.  4. 
The  point  at  which  the  fascia  divides,  to  form  a  sheath  for  the  sterno-mastoid  muscle. 
6.  The  point  of  reunion  of  the  two  layers  of  the  sterno-mastoid  sheath.  7.  The  point 
of  union  of  the  deep  cervical  fascia  of  opposite  sides  of  the  neck.  8.  Section  of 
the  sterno-hyoid.  9.  Omo-hyoid.  10.  Sterno-thyroid.  11.  The  lateral  lobe  of  the 
thyroid  gland.  12.  The  trachea.  13.  The  oesophagus.  14.  The  sheath  containing 
the  common  carotid  artery,  internal  jugular  vein,  and  pneumogastric  nerve.  15.  The 
longus  colli.  The  nerve  in  front  of  the  sheath  of  this  muscle  is  the  sympathetic.  16. 
The  rectus  anticus  major,  17.  Scalenus  anticus.  18.  Scalenus  posticus.  19.  The 
spleniua  capitis.  20.  Splenius  colli.  21.  Levator  anguli  scapulae.  22.  Complexus. 
23.  Trachelo-mastoid.  24.  Transvcrsalis  colli.  25.  Ccrvicalis  asccndcns.  26.  The 
semi-spinalis  colli.  27.  The  multifidus  spinte.  28.  A  cervical  vertebra.  The  trans- 
verse processes  are  seen  to  be  traversed  by  the  vertebral  artery  and  vein. 

*  For  an  excellent  description  of  tliis  fascia,  see  Sir  Astley  Cooper's  work  on  the 
"Anatomy  of  the  Thymus  Gland." 


ABDOMINAL  FASCIiE.  273 

cervical  fascia  ;  the  descending  layer  descends  upon  the  trachea  to 
its  bifurcation,  surrounds  the  large  vessels  arising  from  the  arch  of 
the  aorta,  and  the  upper  part  of  the  arch  itself,  and  is  continuous 
with  the  fibrous  layer  of  the  pericardium.  It  is  connected  also  with 
the  venae  innominatae  and  superior  cava,  and  is  attached  to  the 
cellular  capsule  of  the  thymus  gland. 

"  The  thoracic  fascia,"  writes  Sir  Astley  Cooper,  "  performs  three 
important  offices : 

"  1st.  It  forms  the  upper  boundary  of  the  chest,  as  the  diaphragm 
does  the  lower. 

"2nd.  It  steadily  preserves  the  relative  situation  of  the  parts 
which  enter  and  quit  the  thoracic  opening. 

"  3d.  It  attaches  and  supports  the  heart  in  its  situation,  through 
the  medium  of  its  connexion  with  the  aorta  and  large  vessels  which 
are  placed  at  its  curvature." 

ABDOMINAL     FASCIA. 

The  lower  part  of  the  parietes  of  the  abdomen,  and  the  cavity  of  the 
pelvis,  are  strengthened  by  a  layer  of  fascia  which  lines  their  inter- 
nal surface,  and  at  the  bottom  of  the  latter  cavity  is  reflected  in- 
wards to  the  sides  of  the  bladder.  This  fascia  is  continuous  through- 
out the  whole  of  the  surface ;  but  for  convenience  of  description  it 
is  considered  under  the  several  names  of  transversalis  fascia,  iliac 
fascia,  and  pelvic  fascia ;  the  two  former  meet  at  the  crest  of  the 
ilium,  and  Poupart's  ligament,  and  the  latter  is  confined  to  the  cavity 
of  the  true  pelvis. 

The  fascia  transversalis  (Fascia  Cooperi)*  is  a  cellulo-fibrous 
lamella  which  lines  the  inner  surface  of  the  transversalis  muscle. 
It  is  thick  and  dense  below,  near  the  lower  part  of  the  abdomen ; 
but  becomes  thinner  as  it  ascends,  and  is  gradually  lost  in  the  sub- 
serous cellular  tissue.  It  is  attached  inferiorly  to  the  reflected  margin 
of  Poupart's  ligament  and  to  the  crest  of  the  ilium  ;  internally,  to 
the  border  of  the  rectus  muscle  ;  and  at  the  inner  third  of  the  femoral 
arch,  is  continued  beneath  Poupart's  ligament,  and  forms  the  ante- 
rior segment  of  the  crural  canal,  or  sheath  of  the  femoral  vessels. 

The  internal  abdominal  ring  is  situated  in  this  fascia,  at  about 
midway  between  the  spine  of  the  os  pubis,  and  the  anterior  superior 
spine  of  the  ilium,  and  half  an  inch  above  Poupart's  ligament;  it  is 
bounded  upon  its  inner  side  by  a  well-marked  falciform  border,  but 
is  ill  defined  around  its  outer  margin.  From  the  circumference  of 
this  ring  is  given  off"  an  infundibuliform  process  which  surrounds  the 
testicle  and  spermatic  cord,  constituting  the  fascia  propria  of  the 
latter,  and  forms  the  first  investment  to  the  sac  of  oblique  inguinal 
hernia.  It  is  the  strength  of  this  fascia,  in  the  interval  between  the 
head  of  the  rectus  and  the  internal  abdominal  ring,  that  defends  this 

*  Sir  Astley  Cooper  first  described  tliis  fascia  in  its  important  relation  to  inguinal 
hernia. 


274  INGUINAL  BEBNIA. 

portion  of  the  parietes  from  the  frequent  occurrence  of  direct  in- 
guinal hernia. 

INGUIXAL     HERMA. 

Inguinal  hernia  is  of  two  kinds,  oblique,  and  direct. 

In  oblique  inguinal  hernia  the  intestine  escapes  from  the  cavity 
of  the  abdomen  into  the  spermatic  canal,  through  the  internal  abdo- 
minal ring,  pressing  before  it  a  pouch  of  peritoneum  which  consti- 
tutes the  hernial  sac,  and  distending  the  infundibuliform  process  of 
the  transversalis  fascia.  After  emerging  through  the  internal  abdo- 
minal ring,  it  passes  fi7^st  beneath  the  lower  and  arched  border  of 
the  trans versahs  muscle;  then  beneath  the  lower  border  of  the  in- 
ternal oblique  muscle;  and  finally  through  the  external  abdominal 
ring  in  the  aponeurosis  of  the  external  oblique.  From  the  trans- 
versalis muscle  it  receives  no  investment;  while  passing  beneath  the 
lower  border  of  the  internal  oblique  it  obtains  the  cremaster  muscle  ; 
and,  upon  escaping  at  the  external  abdominal  ring,  receives  the  in- 
tercolumnar  fascia.  So  that  the  coverings  of  an  oblique  inguinal 
hernia,  after  it  has  emerged  through  the  external  abdominal  ring, 
are,  from  the  surface  to  the  intestine,  the 

Integument, 

Superficial  fascia, 

Intercolumnar  fascia, 

Cremaster  muscle, 

Transversalis,  or  infundibuliform  fascia, 

Peritoneal  sac. 

The  spermatic  canal,  which,  in  the  normal  condition  of  the  abdo- 
minal parietes  serves  for  the  passage  of  the  spermatic  cord  in  the 
male,  and  the  round  ligament  with  its  vessels  in  the  female,  is  about 
one  inch  and  a  half  in  length.  It  is  bounded  in  front  by  the  aponeu- 
rosis of  the  external  oblique  muscle ;  behind  by  the  transversalis 
fascia,  and  by  the  conjoined  tendon  of  the  internal  oblique  and  trans- 
versalis muscle;  above  by  the  arched  borders  of  the  internal  oblique 
and  transversalis ;  behio  by  the  grooved  border  of  Poupart's  liga- 
ment ;  and  at  each  extremity  by  one  of  the  abdominal  rings,  the  in- 
ternal ring  at  the  inner  termination,  the  external  ring  at  the  outer 
extremity.  These  relations  may  be  more  distinctly  illustrated  by 
the  following  plan — 

Abate. 
Lower  borders  of  internal  oblique 
and  transversalis  muscle. 
In  Front.  Behind. 

Aponeurosis  of  external 
oblique. 


Spermatic  canal. 


Transversalis  fascia.  Con- 
join(;d  tendon  of  internal 
oblique  and  transversalis. 


Below. 
Grooved  border  of 
Poupart's  ligament 


DIRECT  INGUINAL  HERNIA.  275 

There  are  three  varieties  of  oblique  inguinal  hernia : — common, 
congenital,  and  encysted. 

Common  oblique  hernia  is  that  which  has  been  described  above. 

Congenital  hernia  results  from  the  nonclosure  of  the  pouch  of  peri- 
toneum carried  downwards  into  the  scrotum  by  the  testicle,  during 
its  descent  in  the  foetus. 

The  intestine  at  some  period  of  life  is  forced  into  this  canal,  and 
descends  through  it  into  the  tunica  vaginalis  where  it  lies  in  contact 
with  the  testicle ;  so  that  congenital  hernia  has  no  proper  sac,  but  is 
contained  within  the  tunica  vaginalis.  The  other  coverings  are  the 
same  as  those  of  common  inguinal  hernia. 

Encysted  hernia  (hernia  infantilis,  of  Hey)  is  that  form  of  pro- 
trusion in  which  the  pouch  of  peritoneum  forming  the  tunica  vagi- 
nalis, being  only  partially  closed,  and  remaining  open  externally  to 
the  abdomen,  admits  of  the  hernia  passing  into  the  scrotum,  behind 
the  tunica  vaginalis.  So  that  the  surgeon  in  operating  upon  this 
variety,  requires  to  divide  three  layers  of  serous  membrane  ;  the  first 
and  second  layers  being  those  of  the  tunica  vaginalis ;  and  the  third, 
the  true  sac  of  the  hernia. 

Direct  inguinal  hernia*  has  received  its  name  from  passing  directly 
through  the  external  abdominal  ring,  and  forcing  before  it  the  op- 
posing parietes.  This  portion  of  the  wall  of  the  abdomen  is  strength- 
ened by  the  conjoined  tendon  of  the  internal  oblique  and  transversalis 
muscle,  which  is  pressed  before  the  hernia,  and  forms  one  of  its 
investments.     Its  coverings  are,  the 

Integument, 
Superficial  fascia, 
Intercolumnar  fascia, 
Conjoined  tendon, 
Transversalis  fascia, 
Peritoneal  sac. 

Direct  inguinal  hernia  differs  from  oblique  in  never  attaining  the 
same  bulk,  in  consequence  of  the  resisting  nature  of  the  conjoined 
tendon  of  the  internal  oblique  and  transversalis  and  of  the  transver- 
salis fascia;  in  its  direction,  having  a  tendency  to  protrude  from  the 
middle  line  rather  than  towards  it.  Thirdly,  in  making  for  itself  a 
new  passage  through  the  abdominal  parietes,  instead  of  following 
a  natural  channel ;  and  fourthly,  in  the  relation  of  the  neck  of  its 
sac  to  the  epigastric  artery :  that  vessel  lying  to  the  outer  side  of  the 
opening  of  the  sac  of  direct  hernia,  and  to  the  inner  side  of  oblique 
hernia. 

All  the  forms  of  inguinal  hernia  are  designated  serosa/,  when  they 
have  descended  into  that  cavity. 

^he  fascia  iliaca  is  the  tendino-fibrous  investment  of  the  psoas 
and  iliacus  muscles ;  and,  like  the  fascia  transversalis,  is  thick  be- 
low, and  becomes  gradually  thinner  as  it  ascends.     It  is  attached 

*  Also  known  by  the  name  ventro-ingvinal  hernia. — G. 


276 


PELVIC  LAYER  OR  FASCIA. 


superiorly  along  the  edge  of  the  psoas,  to  the  anterior  lamella  of  the 
aponeurosis  of  the  transversalis  muscle,  to  the  ligamentum  arcuatum 
internum,  and  to  the  bodies  of  the  lumbar  vertebrse,  leaving  arches 
corresponding  with  the  constricted  portions  of  the  vertebrae  for  the 
passage  of  the  lumbar  vessels.  Lower  down  it  passes  beneath  the 
external  iliac  vessels,  and  is  attached  along  the  margin  of  the  true 
pelvis ;  externally,  it  is  connected  to  the  crest  of  the  ilium  ;  and, 
inferiorly,  to  the  outer  two-thirds  of  Poupart's  ligament,  where  it  is 
continuous  with  the  fascia  transversalis.  Passing  beneath  Poupart's 
ligament,  it  surrounds  the  psoas  and  iliacus  muscles  to  their  termi- 
nation, and  beneath  the  inner  third  of  the  femoral  arch  forms  the 
posterior  segment  of  the  sheath  of  the  femoral  vessels. 

The  fascia  pelvica  is  attached  to  the  inner  surface  of  theos  pubis 
and  along  the  margin  of  the  brim  of  the  pelvis,  where  it  is  continu- 
ous with  the  iliac  fascia.  From  this  extensive  origin  it  descends  into 
the  pelvis,  and  divides  into  two  layers,  the  pelvic  and  obturator. 

Fig.  113. 


The  pelvic  layer  or  fascia,  when  traced  from  the  internal  surface 
of  the  OS  pubis  near  to  the  symphysis,  is  seen  to  be  reflected  inwards 
to  the  neck,  of  the  bladder,  so  as  to  form  the  anterior  vesical  liga- 
ments. Traced  backwards,  it  passes  between  the  sacral  plexus  of 
nerves  and  the  internal  iliac  vessels,  and  is  attached  to  the  anterior 
surface  of  the  sacrum  ;  and  followed  from  the  sides  of  the  pelvis,  it 
descends  to  the  base  of  the  bladder  and  divides  into  three  layers, 
one  ascendins,  is  reflected  to  the  side  of  that  viscus,  encloses  the 

Fig.  113.  A  transverse  section  of  the  pelvis,  showing  the  distribution  of  the  pelvic 
fascia.  1.  The  bladder.  2.  The  vesiculse  seminales  divided  across.  3.  The  rectum. 
4.  The  iliac  fascia  covering  in  the  iliacus  and  psoas  muscles  (5) ;  and  forming  a  sheath 
for  the  external  iliac  vessels  (6).  7.  The  anterior  crural  nerve  excluded  from  the  sheath, 
8.  The  pelvic  fascia.  9.  Its  ascending  layer,  forming  the  lateral  ligament  of  the  blad- 
der of  one  side,  and  a  sheath  to  the  vesical  plexus  of  veins.  10.  The  rccto-vcsical  fascia 
of  Mr.  Tyrrell  formed  by  the  middle  layer.  11.  The  inferior  layer  surrounding  the 
rectum  and  meeting  at  the  middle  line  with  the  fascia  of  the  opposite  side.  12.  The 
levator  ani  muscle.  13.  The  obturator  intcrnus  muscle,  covered  in  by  the  obturator 
fascia,  which  also  forms  a  sheath  for  the  internal  pudic  vessels  and  nerve  (14).  15. 
The  layer  of  fascia  which  invests  the  under  surface  of  the  levator  ani  muscle,  the  anal 
fascia. 


OBTURATOR  FASCIA PERINEAL  FASCIA. 


277 


vesical  plexus  of  veins,  and  forms  the  lateral  ligaments  of  the 
bladder.  A  middle  layer  passes  inwards  between  the  base  of  the 
bladder  and  the  upper  surface  of  the  rectum,  and  is  named  by  Mr. 
Tyrrell  the  recto-vesical fascia ;  and  an  inferior  layer  passes  behind 
the  rectum,  and,  with  the  layer  of  the  opposite  side,  completely  in- 
vests that  intestine. 

The  obturator  fascia  passes  directly  downwards  from  the  splitting 
of  the  layers  of  the  pelvic  fascia,  and  covers  in  the  obturator  in- 
ternus  muscle  and  the  internal  pudic  vessels  and  nerve ;  it  is  attached 
to  the  ramus  of  the  os  pubis  and  ischium  in  front,  and  below  to  the 
falciform  margin  of  the  great  sacro-ischiatic  ligament.  Lying  be- 
tween these  two  layers  of  fascia  is  the  levator  ani  muscle,  which 
arises  from  their  angle  of  separation.  The  levator  ani  is  covered 
in  inferiorly  by  a  third  layer  of  fascia,  which  is  given  off  by  the 
obturator  fascia,  and  is  continued  downwards  upon  the  inferior 
surface  of  the  muscle  to  the  extremity  of  the  rectum,  where  it  is 
lost.  This  layer  may  be  named  from  its  position  and  inferior  attach- 
ment the  anal  fascia. 

Fig.  114. 


In  the  perineum  there  are  two  fascise  of  much  importance,  the 
superficial  and  deep  perineal  fascia. 

The  superficial  'perineal  fascia  is  a  thin  tendino-fibrous  layer, 
which  covers  in  the  muscles  of  the  genital  portion  of  the  j)erineum 
and  the  root  of  the  penis.     It  is  firmly  attached  at  each  side  to  the 

Fig.  114.  The  pubic  arch  with  llie  attachments  of  the  perineal  fascise.  1, 1, 1.  The 
superficial  fascia  divided  by  a  V  shaped  incision  into  three  flajis;  the  lateral  flaps  are 
turned  over  the  ramus  of  the  os  pubis  and  iscliium  at  each  side,  to  which  they  are 
firmly  attached  ;  the  posterior  flap  is  conlinuous  with  the  deep  perineal  fascia.  2.  The 
deep  perineal  fascia.  3.  The  opening  for  the  passage  of  tlie  membranous  portion  of 
the  urethra,  previously  to  entering  the  bulb.  4.  Two  projections  of  the  anterior  layer 
ol  the  deep  perineal  fascia,  corresponding  with  COwper's  glands. 


278  DEEP  PERINEAL  FASCIA. 

ramus  of  the  os  pubis  and  ischium  ;  posteriorly  it  is  reflected  back- 
wards beneath  the  transversus  perinei  muscles  to  become  connected 
with  the  deep  perineal  fascia ;  while  anteriorly  it  is  continuous  with 
the  dartos  of  the  scrotum. 

^      Fig.  115. 


The  deef  'perineal fascia  (Camper's  ligament,  triangular  ligannent) 
is  situated  behind  the  root  of  the  penis,  and  is  firmly  stretched  across 
between  the  ramus  of  the  os  pubis  and  ischium  of  each  side  so  as  to 
constitute  a  strong  septum  of  defence  to  the  outlet  of  the  pelvis. 
At  its  inferior  border  it  divides  into  two  layers,  one  of  which  is 
continued  forwards,  and  is  continuous  with  the  superficial  perineal 
fascia ;  while  the  other  is  prolonged  backwards  to  the  rectum,  and 
joining  with  the  anal  fascia  assists  in  supporting  the  extremity  of 
that  intestine.  The  deep  perineal  fascia  is  composed  of  two  layers, 
which  are  separated  from  each  other  by  several  important  parts, 
and  traversed  by  the  membranous  portion  of  the  urethra.  The  ante- 
Fig.  115.  A  side  view  of  the  viscera  of  the  pelvis,  showing  the  distribution  of  the 
perineal  and  pelvic  fasciae.  1 .  The  symphysis  pubis.  2.  The  bladder.  3.  The  recto- 
vesical fold  of  peritoneum,  passing  from  the  anterior  surface  of  the  rectum  to  the  pos- 
terior part  of  the  bladder  ;  from  the  upper  part  of  the  fundus  of  the  bladder  it  is  re- 
flected upon  the  abdominal  parietes.  4.  The  ureter.  5.  The  vas  deferens  crossing  the 
direction  of  the  ureter.  6.  The  vcsicula  seminalis  of  the  right  side.  7,  7.  The  pro- 
state gland  divided  by  a  longitudinal  section.  8,  8.  The  section  of  a  ring  of  elastic 
tissue  encircling  the  prostatic  portion  of  the  urethra  at  its  commencement.  9.  The 
prostJitic  portion  of  the  urethra.  10.  The  membranous  portion,  enclosed  by  the  com. 
pressor  urcthrjB  muscle.  11.  The  commencement  of  the  corpus  spongiosum  penis,  tlie 
bulb.  12.  The  anterior  ligaments  of  the  bladder  formed  by  the  reflection  of  the  pelvic 
fascia,  from  the  internal  surface  of  the  os  pubis  to  the  neck  of  the  bladder.  13.  The 
edge  of  the  pelvic  fascia  at  the  point  where  it  is  reflected  upon  the  rectum.  14.  An 
interval  between  the  pelvic  fascia  and  deep  perineal  fascia,  occupied  by  a  plexus  of 
veins.  15.  The  deep  perineal  fascia  ;  its  two  layers.  16.  Cowper's  gland  of  the  right 
side  situated  between  the  two  layers  below  the  membranous  portion  of  the  urethra.  17. 
The  superficial  perineal  fascia  ascending  in  front  of  the  root  of  the  penis  to  become 
continuous  with  the  dartos  of  the*crotum  (18).  19.  The  layer  of  the  deep  fascia  which 
is  prolonged  to  the  rectum.  20.  The  lower  part  of  the  levator  ani;  its  fibres  are  con- 
cealed by  the  anal  fascia.  21.  The  inferior  segment  of  the  funnel-shaped  process 
given  off  from  tlie  posterior  layer  of  the  deep  perineal  fascia,  which  is  continuous  with 
the  recto-vesical  fascia  of  Tyrrell.  The  attachment  of  this  fascia  to  the  recto-vesical 
fold  of  peritoneum  is  seen  at  22, 


FASCIA  OF  THE  UPPER  EXTREMIXr.  279 

rior  layer  is  nearly  plane  in  its  direction,  and  sends  a  sheath  for- 
wards around  the  anterior  termination  of  the  membranous  urethra 
to  be  attached  to  the  posterior  part  of  the  bulb.  The  posterior  layer 
is  oblique  and  sends  a  funnel-shaped  process  backwards,  which 
invests  the  commencement  of  the  membranous  urethra  and  the  pro- 
state gland.  The  inferior  segment  of  this  funnel-shaped  process  is 
continued  backwards  beneath  the  prostate  gland  and  the  vesiculae 
seminales,  and  is  continuous  with  the  recto- vesical  fascia  of  Tyrrell, 
which  is  attached  posteriorly  to  the  recto-vesical  fold  of  peritoneum, 
and  serves  the  important  office  of  retaining  that  duplicature  in  its 
proper  situation. 

Between  the  two  layers  of  the  deep  perineal  fascia  are  situated, 
therefore,  the  whole  extent  of  the  membranous  portion  of  the  urethra, 
the  compressor  urethrae  muscle,  Cowper's  glands,  the  internal  pudic 
and  bulbous  arteries,  and  a  plexus  of  veins.  Mr.  Tyrrell  considers 
the  anterior  lamella  alone  as  the  deep  perineal  fascia,  and  the  pos- 
terior lamella  as  a  distinct  layer  of  fascia  covering  in  a  considerable 
plexus  of  veins. 

FASCIiE    OF     THE     UPPER     EXTREMITY. 

The  swperficial  fascia  of  the  upper  extremity  contains  between 
its  layers  the  superficial  veins  and  lymphatics,  and  the  superficial 
nerves. 

The  deep  fascia  is  thin  over  the  deltoid  and  pectoralis  major 
muscles,  and  in  the  axillary  space,  but  thick  upon  the  dorsum  of  the 
scapula,  where  it  binds  down  the  infra-spinatus  muscle.  It  is  at- 
tached to  the  clavicle,  acromion  process,  and  spine  of  the  scapula. 
Jn  the  upper  arm  it  is  somewhat  stronger,  and  is  inserted  into  the 
condyloid  ridges,  forming  the  intermuscular  septa.  In  the  fore-arm 
it  is  very  strong,  and  at  the  bend  of  the  elbow  its  thickness  is  aug- 
mented by  a  broad  band,  which  is  given  off  from  the  inner  side  of 
the  tendon  of  the  biceps.  It  is  firmly  attached  to  the  olecranon 
process,  to  the  ulna,  and  to  the  prominent  points  about  the  wrist. 
Upon  the  front  of  the  wrist  it  is  continuous  with  the  anterior  annular 
ligament,  which  is  considered  by  some  anatomists  to  be  formed  by 
the  deep  fascia,  but  which  I  am  more  disposed  to  regard  as  a  liga- 
ment of  the  wrist.  On  the  posterior  aspect  of  this  joint  it  forms  a 
strong  transverse  band,  the  'posterior  annular  //g'amen^,  beneath  which 
the  tendons  of  the  extensor  muscles  pass,  in  distinct  sheaths. 

The  tendons  as  they  pass  beneath  the  annular  ligaments  are 
surrounded  by  synovial  bursas.  The  dorsum  of  the  hand  is  invested 
by  a  thin  fascia,  which  is  continuous  with  the  posterior  annular 
ligament. 

The  palmar  fascia  is  divided  into  three  portions.  A  central  por- 
tion, which  occupies  the  middle  of  the  palm,  and  two  lateral  por- 
tions, which  spread  out  over  the  sides  of  the  hand,  and  are  continuous 
with  the  dorsal  fascia.  The  central  portion  is  strong  and  tendinous ; 
it  is  narrow  at  the  wrist,  where  it  is  attached  to  the  annular  liga- 


280  FASCI-E  OF  THE  LOAVER  EXTREMIXr. 

ment,  and  broad  over  the  heads  of  the  metacarpal  bones,  where  it 
divides  into  eight  slips,  which  are  inserted  into  the  sides  of  the  bases 
of  the  phalanges  of  each  finger.  The  fascia  is  strengthened  at  its 
point  of  division  into  slips  by  strong  fasciculi  of  transverse  fibres, 
and  the  arched  interval  left  between  the  slips  gives  passage  to  the 
tendons  of  the  flexor  muscles.  The  arches  between  the  fingers 
transmit  the  digital  vessels  and  nerves,  and  lumbricales  muscles. 

TASCI^     OF     THE     LOWER     EXTREMITY. 

The  superficial  fascia  contains  between  its  two  layers  the  super- 
ficial vessels  and  nerves  of  the  lower  extremity.  At  the  groin  these 
two  layers  are  separated  from  each  other  by  the  superficial  lymphatic 
glands,  and  the  deeper  layer  is  attached  to  Poupart's  ligament, 
while  the  superficial  layer  is  continuous  with  the  superficial  fascia 
of  the  abdomen. 

The  deep  fascia  of  the  thigh  is  named,  from  its  great  extent,  the 
fascia  lata;  it  is  thick  and  strong  upon  the  outer  side  of  the  limb, 
and  thinner  upon  its  inner  and  posterior  side.  That  portion  of  fascia 
which  invests  the  gluteus  maximus  is  very  thin,  but  that  which  covers 
in  the  gluteus  medius  is  excessively  thick,  and  gives  origin,  by  its 
inner  surface,  to  the  superficial  fibres  of  that  muscle.  The  fascia 
lata  is  attached  superiorly  to  Poupart's  ligament,  the  crest  of  the 
ilium,  sacrum,  coccyx,  tuberosity  of  the  ischium,  ramus  of  the 
ischium  and  os  pubis  and  body  of  the  os  pubis;  in  the  thigh  it  is 
inserted  into  the  linea  aspera,  and  around  the  knee  is  connected  with 
the  prominent  points  of  that  joint.  It  possesses  also  two  muscular 
attachments, — by  means  of  the  tensor  vaginas  femoris,  which  is 
inserted  between  its  two  layers  on  the  outer  side,  and  the  gluteus 
maximus  which  is  attached  to  it  behind. 

In  addition  to  the  smaller  openings  in  the  fascia  lata  which  trans- 
mit the  small  cutaneous  vessels  and  nerves,  there  exists  at  the  upper 
and  inner  extremity  of  the  thigh  an  oblique  foramen,  which  gives 
passage  to  the  superficial  lymphatic  vessels,  and  the  large  subcu- 
taneous vein  of  the  lower  extremity,  the  internal  saphenous  vein,  and 
is  thence  named  the  saphenous  openivg.  The  existence  of  this 
opening  has  given  rise  to  the  division  of  the  upper  part  of  the  fascia 
lata  into  two  portions,  an  iliac  portion  and  a  pubic  portion. 

The  iliac  portion  is  situated  upon  the  iliac  side  of  the  opening. 
It  is  attached  to  the  crest  of  the  ilium,  and  along  Poupart's  ligament 
to  the  spine  of  the  os  pubis,  where  it  is  reflected  downwards  and 
outwards  in  an  arched  direction,  and  forms  a  falciform  border,  which 
constitutes  the  outer  boundary  of  the  saphenous  opening.  The  edge 
of  this  border  immediately  overlies,  and  is  reflected  upon,  the  sheath 
of  the  femoral  vessels,  and  the  lower  extremity  of  the  curve  is  con- 
tinuous with  the  pubic  portion. 

The  puhic  portion,  occupying  the  pubic  side  of  the  saphenous 
opening,  is  attached  to  the  spine  of  the  os  pubis*and  pectineal  line; 
ftnd,  passing  outwards  behind  the  sheath  of  the  femoral  vessels, 


FASCIA  LATA — FEMORAL  RING. 


2S1 


divides  into  two  layers;  the  anterior  layer  is  continuous  with  that 
portion  of  the  iliac  fascia  which  forms  the  sheath  of  the  iliacus  and 
psoas  muscles,  and  the  posterior  layer  is  lost  upon  the  capsule  of 
the  hip-joint. 

The  interval  between  the  falciform  border  of  the  iliac  portion  and 
the  opposite  surface  of  the  pubic  portion  is  closed  by  a  fibrous  layer, 
which  is  pierced  by  numerous  openings  for  the  passage  of  lymphatic 
vessels,  and  is  thence  named  cribriform  fascia.  The  cribriform 
fascia  is  connected  with  the  sheath  of  the  femoral  vessels,  and  forms 
one  of  the  coverings  of  femoral  hernia.  When  the  iliac  portion  of 
the  fascia  lata  is  removed  from  its  attachment  to  Poupart's  ligament 
and  is  turned  aside,  the  sheath  of  the  femoral  vessels  (the  femoral 
or  crural  canal)  is  brought  into  view  ;  and  if  Poupart's  ligament  be 

Fig.  116. 


carefully  divided,  the  sheath  may  be  isolated,  and  its  continuation 
with  the  transversalis  and  iliac  fascia  clearly  demonstrated.  In  this 
view  the  sheath  of  the  femoral  vessels  is  an  infundibuliform  continua- 
tion of  the  abdominal  fasciae,  closely  adherent  to  the  vessels,  a  little 
way  down  the  thigh,  but  much  larger  than  the  vessels  it  contains  at 

Fig.  116.  A  section  of  the  structures  which  pass  beneath  the  femoral  arch.  1.  Pou- 
part's ligament.  2,  2.  The  iliac  portion  of  the  fascia  lata,  attached  along  the  margin 
of  the  crest  of  the  ilium,  and  along  Poupart's  ligament,  as  far  as  the  spine  of  the  os 
pubis  (3).  4.  The  pubic  portion  of  the  fascia  lata,  continuous  at  3  with  the  iliac  por- 
tion, and  passing  outwards  behind  the  sheath  of  the  femoral  vessels  to  its  outer  border 
at  5,  where  it  divides  into  two  layers  ;  one  is  continuous  with  the  sheath  of  the  psoas 
(6)  and  iliacus  (7) ;  the  other  (8)  is  lost  upon  the  capsule  of  the  hip-joint  (9).  10.  The 
femoral  nerve,  enclosed  in  the  sheath  of  tlie  psoas  and  iliacus.  11.  Giinbernat's  liga- 
ment.  12.  The  femoral  ring,  within  the  femoral  sheath.  13.  The  femoral  vein.  \\. 
The  femoral  artery  :  the  two  vessels  and  the  ring  are  surrounded  by  the  femoral  sheath, 
and  thin  septa  are  sent  between  the  anterior  and  posterior  wall  of  the  sheath,  dividinor 
the  artery  from  the  vein,  and  the  vein  from  the  femoral  ring. 

24* 


2S2  FE3IORAL  HERNIA. 

Poupart's  ligament.  If  the  sheath  be  opened,  the  artery  and  vein 
will  be  found  lying  side  by  side,  and  occupying  the  outer  two-thirds 
of  the  sheath,  leaving  an  infundibuliform  interval  between  the  vein 
and  the,  inner  wall  of  the  sheath.  The  superior  opening  of  this 
space  is  named  {he  fumoi-al  ring ;  it  is  bounded  in  front  by  Poupart's 
ligament,  behind  by  the  os  pubis,  internally  by  Gimbernat's  ligament, 
and  externally  by  the  femoral  vein.  The  interval  itself  serves  for 
the  passage  of  the  superficial  lymphatic  vessels  from  the  saphenous 
opening  to  a  lymphatic  gland,  which  generally  occupies  the  femoral 
ring ;  and  from  thence  they  proceed  into  the  current  of  the  deep 
lymphatics.  The  femoral  ring  is  closed  merely  by  a  thin  layer  of 
subserous  cellular  tissue,*  which  retains  the  lymphatic  gland  in  its 
position,  and  is  named  septum  crurale ;  and  by  the  peritoneum.  It 
follows  from  this  description,  that  the  femoral  ring  must  be  a  weak 
point  in  the  parieles  of  the  abdomen,  particularly  in  the  female, 
where  the  femoral  arch,  or  space  included  between  Poupart's  liga- 
ment and  the  border  of  the  pelvis,  is  larger  than  in  the  male,  while 
the  structures  which  pass  through  it  are  smaller.  It  happens  con- 
sequently, that  if  violent  or  continued  pressure  be  made  upon  the 
abdominal  viscera,  a  portion  of  intestine  may  be  forced  through  the 
femoral  ring  into  the  infundibuliform  space  in  the  sheath  of  the 
femoral  vessels,  carrying  before  it  the  peritoneum  and  the  septum 
crurale, — this  constitutes /ewoj^aZ  hernia.  If  the  causes  which  give 
rise  to  the  formation  of  this  hernia  continue,  the  intestine,  unable  to 
extend  further  down  the  sheath,  from  its  close  connexion  to  the  ves- 
sels, will  in  the  next  place  be  forced  forwards  through  the  saphenous 
opening  in  the  fascia  lata,  carrying  before  it  two  additional  cover- 
ings, the  sheath  of  the  vessels,  or  fascia  propria,  and  the  cribriform 
fascia,  and  then  curving  upwards  over  Poupart's  ligament,  will 
become  placed  beneath  the  superficial  fascia  and  integument. 

The  direction  which  femoral  hernia  takes  in  its  descent  is  at  first 
doionwards,  then  forivards,  and  then  upwards ;  and  in  endeavouring 
to  reduce  it,  the  application  of  the  taxis  must  have  reference  to  this 
course,  and  be  directed  in  precisely  the  reverse  order.  The  cover- 
ings of  femoral  hernia  are  the 


'a^ 


Integument, 
Superficial  fascia, 
Cribriform  fascia. 
Fascia  propria, 
Septum  crurale. 
Peritoneal  sac. 

The  fascia  of  the  leg  is  strong  in  the  anterior  tibial  region,  and 
gives  origin  by  its  inner  surface  to  the  upper  part  of  the  tibialis  anti- 
cus,  and  extensor  longus  digitorum  muscles. 

*  Tliis  cellular  tissue  is  somelimos  very  considernbly  thickened  by  a  deposit  of  fat 
witiiin  its  cells,  and  Ibrnis  a  thick  stratum  over  the  hernial  sac. 


FASCIiE  OF  THE  LEG.  283 

It  is  firmly  attached  to  the  tibia  and  fibula  at  each  side,  and  be- 
comes thickened  inferiorly  into  a  narrow  band,  the  anterior  annular 
ligament,  beneath  which  the  tendons  of  the  extensor  muscles  pass 
into  the  dorsum  of  the  foot  in  distinct  sheaths,  lined  by  synovial 
bursas.  Upon  the  outer  side  it  forms  a  distinct  sheath  which 
envelopes  the  peronei  muscles,  and  ties  them  to  the  fibula.  The 
anterior  annular  ligament  is  attached  by  one  extremity  to  the  outer 
side  of  the  os  calcis,  and  divides  in  front  of  the  joint  into  two  bands ; 
one  of  which  is  inserted  into  the  inner  malleolus,  while  the  other 
spreads  over  the  inner  side  of  the  foot,  and  becomes  continuous 
with  the  internal  portion  of  the  plantar  fascia. 

The  fascia  of  the  dorsum  of  the  foot  is  a  thin  layer  given  oflf 
from  the  lower  border  of  the  anterior  annular  ligament ;  it  is  con- 
tinuous at  each  side  with  the  lateral  portions  of  the  plantar  fascia. 

The.  fascia  of  the  posterior  fart  of  the  leg  is  much  thinner  than  the 
anterior,  and  consists  of  two  layers,  superficial  and  deep.  The 
superficial  layer  is  continuous  with  the  posterior  fascia  of  the  thigh, 
and  fs  increased  in  thickness  upon  the  outer  side  of  the  leg  by  an 
expansion  derived  from  the  tendon  of  the  biceps ;  it  terminates 
inferiorly  in  the  external  and  internal  annular  ligaments.  The  deep 
layer  is  stretched  across  between  the  tibia  and  fibula,  and  forms  the 
intermuscular  fascia  between  the  superficial  and  deep  layer  of 
muscles.  It  covers  in  superiorly  the  popliteus  muscle,  receiving  a 
tendinous  expansion  from  the  semi-membranosus  muscle,  and  is 
attached  to  the  obliqi^e  line  of  the  tibia. 

The  internal  annular  ligament  is  a  strong  fibrous  band  attached 
above  to  the  internal  malleolus,  and  below  to  the  side  of  the  inner 
tuberosity  of  the  os  calcis.  It  is  continuous  above  with  the  poste- 
rior fascia  of  the  leg,  and  below  with  the  plantar  fascia,  forming 
sheaths  for  the  passage  of  the  flexor  tendons  and  vessels,  into  the 
sole  of  the  foot. 

The  external  annular  ligament,  shorter  than  the  internal,  extends 
from  the  extremity  of  the  outer  malleolus  to  the  side  of  the  os  calcis, 
and  serves  to  bind  down  the  tendons  of  the  peronei  muscles  in  their 
passage  beneath  the  external  ankle. 

The  plantar  fascia  consists  of  three  portions,  a  middle  and  two 
lateral. 

The  middle  pm'tion  is  thick  and  dense,  and  is  composed  of  strong 
tendinous  fibres,  closely  interwoven  with  each  other.  It  is  attached 
posteriorly  to  the  inner  tuberosity  of  the  os  calcis,  and  terminates 
under  the  heads  of  the  metatarsal  bones  in  five  fasciculi.  Each  of 
these  fasciculi  divides  into  two  slips,  which  are  inserted  into  each 
side  of  the  bases  of  the  first  phalanges  of  the  toes,  leaving  an  interval 
between  them  for  the  passage  of  the  flexor  tendons.  The  point  of 
division  of  this  fascia  into  fasciculi  and  slips,  is  strengthened  by 
transverse  bands,  which  preserve  the  solidity  of  the  fascia  at  its 
broadest  part.  The  intervals  between  the  toes  give  passage  to  the 
digital  arteries  and  nerves  and  the  lumbricales  muscles. 

The  lateral  portions  are  thin,  and  cover  the  sides  of  the  sole  of 


284  PLANTAR  FASCIA. 

the  foot ;  they  are  continuous  behind  with  the  internal  and  external 
annular  ligaments ;  on  the  inner  side  with  the  middle  portion,  and 
externally  with  the  dorsal  fascia. 

Besides  constituting  a  strong  layer  of  investment  and  defence  to 
the  soft  parts  situated  in  the  sole  of  the  foot,  these  three  portions  of 
fascia  send  processes  inwards,  which  form  sheaths  for  the  different 
muscles.  A  strong  septum  is  given  off  from  each  side  of  the  middle 
portion  of  the  plantar  fascia,  which  is  attached  to  the  tarsal  bones, 
and  divides  the  muscles  into  three  groups,  a  middle  and  two  lateral; 
and  transverse  septa  are  stretched  between  these  to  separate  the 
layers.  The  superficial  layer  of  muscles  derive  a  part  of  their 
origin  from  the  plantar  fascia. 


CHAPTER    V. 

ON  THE  ARTERIES. 

The  arteries  are  the  cylindrical  tubes  which  convey  the  blood 
from  the  ventricles  of  the  heart  to  every  part  of  the  body.  They 
are  dense  in  structure,  and  preserve  for  the  most  part  the  cylindrical 
form  when  emptied  of  their  blood,  which  is  their  condition  after 
death :  hence  they  were  considered  by  the  ancients,  as  the  vessels 
for  the  transmission  of  the  vital  spirits,*  and  were  therefore  named 
arteries  (drj^  tyi^sTv,  to  contain  air). 

The  artery  proceeding  from  the  left  ventricle  of  the  heart  con- 
tains the  pure  or  arterial  blood,  which  is  distributed  throughout  the 
entire  system,  and  constitutes  with  its  returning  veins  the  greater  or 
systemic  circulation.  That  which  emanates  from  the  right  ventricle, 
conveys  the  impure  blood  to  the  lungs;  and  with  its  corresponding 
veins  establishes  the  lesser  or  pulmonary  circulation. 

The  whole  of  the  arteries  of  the  systemic  circulation  proceed 
from  a  single  trunk,  named  the  aorta,  from  which  they  are  given 
off  as  branches,  and  divide  and  subdivide  to  their  ultimate  ramifi- 
cations, constituting  the  great  arterial  tree  which  pervades  by  its 
minute  subdivisions  every  part  of  the  animal  frame.  The  mode  in 
which  the  division  into  branches  takes  place  is  deserving  of  remark. 
From  the  aorta  the  branches,  for  the  most  part,  pass  off  at  right 
angles,  as  if  for  the  purpose  of  checking  the  impetus  with  which 
the  blood  would  otherwise  rush  along  their  cylinders  from  the  main 
trunk ;  but  in  the  limbs  a  very  different  arrangement  is  adopted ; 
the  branches  are  given  off  from  the  principal  artery  at  an  acute 
angle,  so  that  no  impediment  may  be  offered  to  the  free  circulation 
of  the  vital  fluid.  The  division  of  arteries  is  usually  dichotomous, 
as  of  the  aorta  into  the  two  common  iliacs,  common  carotid  into 
the  external  and  internal,  &c. ;  but  in  some  few  instances  a  short 
trunk  divides  suddenly  into  several  branches  which  proceed  in 
different  directions ;  this  mode  of  division  is  termed  an  axis,  as  the 
thyroid  and  coeliac  axis. 

In  the  division  of  an  artery  into  two  branches,  it  is  observed  that 
the  combined  arese  of  the  two  branches  are  greater  than  that  of  the 
single  trunk ;  and  if  the  combined  arose  of  all  the  branches  at  the 
periphery  of  the  body  were  compared  with  that  of  the  aorta,  it 
would  be  seen  that  the  blood,  in  passing  from  the  aorta  into  the 

*  To  Galen  is  due  the  honour  of  liaving  discovered  that  arteries  contained  blood,  and 
not  air. 


286  STRUCTURE  OF  ARTERIES. 

numerous  distributing  branches,  was  flowing  through  a  conical  tube 
of  which  the  apex  might  be  represented  by  the  aorta,  and  the  base 
by  the  surface  of  the  entire  body.  The  advantage  of  this  important 
principle  in  faciHtating  the  circulation  is  sufficiently  obvious ;  for 
the  increased  channel  which  is  thus  provided  for  the  current  of  the 
blood,  serves  to  compensate  the  retarding  influence  of  friction, 
resulting  from  the  distance  of  the  heart  and  the  division  of  the 
vessels. 

Communications  between  arteries  are  very  free  and  numerous, 
and  increase  in  frequency  with  the  diminution  in  the  size  of  the 
branches ;  so  that  through  the  medium  of  the  minute  ramifications, 
the  entire  body  may  be  considered  as  one  uninterrupted  circle  of 
inosculations  or  anastomoses  (ava  between,  tfrofxa  inouth).  This  in- 
crease in  the  frequency  of  anastomosis  in  the  smaller  branches  is  a 
provision  for  counteracting  the  greater  liability  to  impediment  exist- 
ing in  them  than  in  the  larger  branches.  Where  freedom  of  circula- 
tion is  of  vital  importance,  this  communication  of  the  arteries  is 
very  remarkable,  as  in  the  circle  of  Willis  in  the  cranium,  or  in  the 
distribution  of  the  arteries  of  the  heart.  It  is  also  strikingly  seen  in 
situations  where  obstruction  is  most  likely  to  occur,  as  in  the  dis- 
tribution to  the  alimentary  canal,  around  joints,  or  in  the  hand  and 
foot.  Upon  this  free  communication  existing  every  where  between 
arterial  branches  is  founded  the  principle  of  cure  in  the  ligature  of 
large  arteries  ;  the  ramifications  of  the  branches  given  off"  from  the 
artery  above  the  ligature  inosculate  with  those  which  proceed  from 
the  trunk  of  the  vessel  below  the  ligature;  these  anastomosing 
branches  enlarge  and  constitute  a  collateral  circulation,  in  which,  as 
is  shown  in  the  beautiful  preparations  made  by  Sir  Astley  Cooper, 
several  large  branches  perform  the  office  of  the  single  obliterated 
trunk.* 

The  arteries  do  not  terminate  directly  in  veins ;  but  in  an  inter- 
mediate system  of  vessels,  which,  from  their  minute  size,  are  termed 
capillaries  (capillus,  a  hair).  The  capillaries  constitute  a  micro- 
scopic network,  which  is  distributed  through  every  part  of  the  body, 
so  as  to  render  it  impossible  to  introduce  the  smallest  needle-point 
beneath  the  skin  without  wounding  several  of  these  fine  vessels.  It 
is  through  the  medium  of  the  capillaries  that  all  the  phenomena 
of  nutrition  and  secretion  are  performed.  They  are  remai'kable 
for  their  uniformity  of  diameter,  and  for  the  constant  divisions  and 
communications  which  take  place  between  them  without  any  alter- 
ation of  size.  They  inosculate  on  one  hand  with  the  terminal 
ramusculi  of  the  arteries  ;  and  on  the  other  with  the  minute  radicles 
of  the  veins. 

Arteries  are  composed  of  three  coats,  external,  middle,  and  in- 
ternal. The  external  or  cellular  coat  is  firm  and  strong,  and  serves 
at  the  same  time  as  the  chief  means  of  resistance  of  the  vessel,  and 

*  I  have  a  preparation,  showing  the  collateral  circulation  in  a  dog,  in  whom  I  tied 
the  abdominal  aorta ;  the  animal  died  from  over-feeding  nearly  two  years  after  the 
operation. 


AOBTA.  287 

of  connexion  to  surrounding  parts.  It  consists  of  condensed  cellular 
tissue,  strengthened  by  an  interlacement  of  glistening  fibres  which 
partially  encircle  the  cylinder  of  the  tube  in  an  oblique  direction. 
Upon  the  surface  the  cellular  tissue  is  loose,  to  permit  of  the  move- 
ments of  the  artery  in  distention  and  contraction. 

The  middle  or  fibrous  coat  is  composed  of  yellowish  fibres  of 
elastic  tissue,  which  are  disposed  in  an  oblique  direction  around  the 
cylinder  of  the  vessel,  and  cross  each  other  in  their  course.  This 
coat  is  elastic  and  fragile,  and  thicker  than  the  external  coat.  Its 
elasticity  enables  the  vessel  to  accommodate  itself  to  the  quantity  of 
blood  which  it  may  contain  ;  its  fragility  is  exhibited  in  some  cases 
of  aneurism,  and  in  the  division  of  the  two  internal  coats  of  an 
artery  by  a  ligature. 

The  internal  coat  is  a  thin  serous  membrane  which  lines  the  in- 
terior of  the  artery,  and  gives  it  the  smooth  polish  which  that  sur- 
face presents.  It  is  continuous  with  the  lining  membrane  of  the 
heart,  and  through  the  medium  of  the  capillaries  with  the  venous 
system.  The  internal  is  connected  to  the  fibrous  coat  by  a  close 
cellular  tissue,  which  is  very  liable  to  disease  and  depositions  of 
various  kinds ;  and  is  the  seat  of  the  first  changes  which  precede 
aneurism.  The  researches  of  Henle  have  demonstrated  an  epithe- 
lium, composed  of  vesicles  and  scales,  with  central  nuclei,  upon  the 
surface  of  this  internal  coat,  analogous  to  the  epithelium  of  serous 
and  mucous  membranes. 

The  arteries  in  their  distribution  through  the  body  are  included 
in  a  loose  cellular  investment  which  separates  them  from  the  sur- 
rounding tissues,  and  is  called  a  sheath.  Around  the  principal  ves- 
sels the  sheath  is  an  important  structure ;  it  is  composed  of  cellulo- 
fibrous  tissue,  intermingled  with  tendinous  fibres,  and  is  continuous 
with  the  fascice  of  the  region  in  which  the  arteries  are  situated,  as 
with  the  thoracic  and  cervical  fascias  in  the  neck,  transversalis  and 
iliac  fascise,  and  fascia  lata  in  the  thigh,  &c.  The  sheath  of  the 
arteries  contains  also  their  accompanying  veins,  and  sometimes  a 
nerve. 

The  coats  of  arteries  are  supplied  with  blood  like  other  organs  of 
the  body,  and  the  vessels  which  are  distributed  to  them  are  named 
Vasa  vasorum.  They  are  also  provided  with  nerves ;  but  the  mode 
of  distribution  of  the  nerves  is  at  present  undiscovered. 

In  the  consideration  of  the  arteries,  we  shall  first  describe  the 
aorta,  and  the  branches  of  that  trunk,  with  their  subdivisions,  which 
together  constitute  the  efferent  portion  of  ihe  systemic  circulatior\; 
and  then  the  pulmonary  artery  as  the  efferent  trunk  of  the  pulmo- 
nary circulation. 

AORTA. 

The  Aorta  arises  from  the  left  ventricle,  at  the  middle  of  the  root 
of  the  heart,  opposite  the  articulation  of  the  fourth  costal  cartilage 
with  the  sternum.     At  its  commencement  it  presents  three  dilata- 


288 


AORTA. 


tions,  called  the  sinus  aortici,  which  correspond  with  the  semilunar 
valves.  It  ascends  at  first  to  the  right,  then  curves  backwards  and 
to  the  left,  and  descends  on  the  left  side  of  the  vertebral  column  to 
the  fourth  lumbar  vertebra.  Hence  it  is  divided  into — ascending — 
arch — and  descending  aorta. 

Relations. — The  ascending  aorta  has  in  relation  with  it,  in  front, 
the  trunk  of  the  pulmonary  artery,  thoracic  fascia,  and  pericardium; 
behind,  the  right  pulmonary  veins  and  artery ;  to  the  right  side,  the 
right  auricle  and  superior  cava  ;  and  to  the  'left,  the  left  auricle  and 
the  trunk  of  the  pulmonary  artery. 

Fig.  117. 


Fig.  117.  The  large  vessels  which  proceed  from  the  root  of  the  heart,  with  their  re- 
lations;  the  heart  has  been  removed.  1.  The  ascending  aorta.  2.  The  arch.  3.  The 
tlioracic  portion  of  the  descending  aorta.  4.  The  arteria  innominata  dividing  into,  5, 
the  right  carotid,  which  again  divides  at  6,  into  the  external  and  internal  carotid  ;  and 
7,  the  right  subclavian  artery.  8.  The  axillary  artery;  its  extent  is  designated  by  a 
dotted  line.  9.  The  brachial  artery.  10.  The  right  pneumogastric  nerve  running  by 
the  side  of  the  common  carotid,  in  front  of  the  right  subclavian  artery,  and  behind  the 
root  of  the  right  lung.  II.  The  left  common  carotid,  having  to  its  outer  side  the  left 
pneumogastric  nerve,  which  crosses  the  arch  of  the  aorta,  and  as  it  reaches  its  lower 
border  is  seen  to  give  off  the  left  recurrent  nerve.  12.  The  left  subclaviiin  artery  be- 
coming axillary,  and  bracliial  in  its  course,  like  the  artery  of  the  opposite  side.  13. 
The  trunk  of  the  pulmonary  artery  connected  to  the  concavity  of  the  arch  of  the  aorta 
by  a  fibrous  cord,  the  rcrnuina  ol'tlie  ductus  arteriosus.  14.  The  left  pulmonary  artery. 
1.5.  The  right  pulmonary  artery.  16.  The  trachea.  17-  The  right  bronchus.  18. 
The  left  bronchus.  Hi,  19.  The  pulmonary  veins.  17,  l.*),  and  19,  on  tlie  right  side, 
and  14,  18,  and  19,  on  the  left,  constitute  the  roots  of  the  corresponding  lungs,  and  the 
relative  position  of  these  vessels  is  carefully  preserved.  20,  Bronchial  arteries.  21,21, 
Intercostal  arteries;  the  branches  from  the  front  of  the  aorta  above  and  below  the 
number  3  are  pericardiac  and  oesophageal  branches. 


ASCENDING  AORTA ARCH. 


289 


Plan  of  the  relations  of  the  ascending  Aorta. 

In  Front. 
Pericardium, 
Thoracic  fascia, 
Pulmonary  artery, 


Right  Side. 
Superior  cava, 
Right  auricle. 


Ascending:  Aorta. 


Left  Side. 
Pulmonary  artery. 
Left  auricle. 


Behind. 
Right  pulmonary  artery, 
Right  pulmonary  veins. 

Jlrcfi. — The  upper  border  of  the  arch  is  parellel  with  the  upper 
border  of  the  second  sterno-costal  articulation  of  the  right  side  in 
front,  and  the  second  dorsal  vertebra  behind,  and  terminates  oppo- 
site the  lower  border  of  the  third. 

The  anterior  surface  of  the  arch  is  crossed  by  the  left  pneumo- 
gastric  nerve,  and  by  the  cardiac  branches  of  that  nerve,  and  of 
the  sympathetic. 

The  posterior  surface  of  the  arch  is  in  relation  with  the  bifurca- 
tion of  the  trachea  and  great  cardiac  plexus,  the  cardiac  nerves, 
left  recurrent  nerve,  and  the  thoracic  duct. 

The  superior  border  gives  off  the  three  great  arteries,  viz.  the 
innominata,  left  carotid,  and  left  subclavian. 

The  inferior  border,  or  concavity  of  the  arch,  is  in  relation  with 
the  remains  of  the  ductus  arteriosus,  the  cardiac  ganglion  and 
left  recurrent  nerve,  and  has  passing  beneath  it  the  right  pulmonary 
artery  and  left  bronchus. 

Plan  of  the  relations  of  the  arch  of  the  Aorta. 

Above.  * 

Arteria  innominata, 
Left  carotid, 
Left  subclavian. 


In  Front. 


Left  pneumogastric  nerve. 
Cardiac  nerves. 


Behind. 
Bifurcation  of  the  trachea. 
Great  cardiac  plexus, 
Cardiac  nerves, 
Left  recurrent  nerve. 
Thoracic  duct. 


Below. 
Cardiac  ganglion, 
Remains  of  ductus  arteriosus. 
Left  recurrent  nerve. 
Right  pulmonary  artery, 
Leil  bronchus. 


The  descending  aorta  is  subdivided,  in  correspondence  with  the 
two  great  cavities  of  the  trunk,  into  the  thoracic  and  abdominal 
aorta. 

25 


290 


THOEACIC  AORTA ABDOMINAL  AORTA. 


The  thoracic  aorta  is  situated  to  the  left  side  of  the  vertebral 
column,  but  approaches  the  middle  line  as  it  descends,  and  at  the 
aortic  opening  of  the  diaphragm  is  altogether  in  front  of  the  column. 
After  entering  the  abdomen  it  again  falls  back  to  the  left  side. 

Relations. — It  is  in  relation,  behind  with  the  vertebral  column  and 
lesser  vena  azygos  ;  in  front  with  the  oesophagus  and  right  pneu- 
mogastric  nerve;  to  the  left  side  with  the  pleura;  and  to  the  right 
with  the  thoracic  duct. 

Plan  of  the  relations  of  the  thoracic  Aorta. 

In  Front. 
(Esophagus, 
Right  pneumogastric  nerve. 


Right  Side. 
Thoracic  duct. 


Thoracic  Aorta. 


Left  Side. 
Pleura. 


Behind. 

Lesser  vena  azygos, 
Vertebral  column. 


The  abdominal  aorta  enters  the  abdomen  through  the  aortic 
opening  of  the  diaphragm,  and  descends,  lying  rather  to  the  left 
side  of  the  vertebral  column,  to  the  fourth  lumbar  vertebra,  where 
it  divides  into  the  two  common  iliac  arteries. 

Relations. — It  is  crossed,  in  front  by  the  left  renal  vein,  pancreas, 
transverse  duodenum,  and  mesentery,  and  is  embraced  by  the  aortic 
plexus:  behind  it  is  in  relation  with  the  thoracic  duct,  receptaculum 
chyli,  and  left  lumbar  veins. 

On  its  left  side  is  the  left  semilunar  ganglion  and  sympathetic 
nerve;  and  on  the  right  the  vena  cava,  right  semilunar  ganglion, 
and  the  commencement  of  the  vena  azygos. 


Plan  of  the  isolations  of  the  abdominal  Aorta. 

In  Front, 
Left  renal  vein, 
Pancreas, 

Transverse  duodenum, 
Mesentery, 
Aortic  plexus. 


Right  Side. 
Vena  cava, 

Right  semilunar  ganglion, 
Vena  azygos. 


Abdominal  Aorta. 


Behind. 
T'horacic  duct, 
Receptaculum  chyli, 
Left  lumbar  veins. 


Left  Side. 
Left  semilunar  gan- 
glion, 
Sympathetic  nerve. 


ARTERIA  INNOMINATA. 


291 


Branches. — The 
form,  are — 

Ascending  aorta. 


Jlrch  of  the  aorta. 


Thoracic  aorta 


branches  of  the  aorta,  arranged  in  a  tabular 


Coronary. 

C  Arteria  innominata, 
<  Left  carotid, 
f  Left  subclavian. 

Pericardiac, 
Bronchial, 
QEsophageal, 
Intercostal. 


Right  carotid, 
Right  subclavian. 


Phrenic, 

Coeliac  axis. 


Abdominal  aorta 


Gastric, 

Hepatic, 
(  Splenic. 
Supra-renal,  or  capsular, 
Renal,  or  emulgent, 
Superior  mesenteric. 
Spermatic, 
Inferior  mesenteric. 
Lumbar, 
Sacra-media, 
Common  iliacs. 

The  coronary  arteries  arise  from  the  aortic  sinuses  at  the  com- 
mencement of  the  ascending  aorta,  immediately  above  the  free 
margin  of  the  semilunar  valves.  The  left,  or  anterior  coronary  passes 
forwards,  between  the  pulmonary  artery  and  left  appendix  auriculae, 
and  divides  into  two  branches  ;  one  of  which  winds  around  the 
base  of  the  left  ventricle,  in  the  auriculo-ventricular  groove,  and 
inosculates  with  the  right  coronary,  forming  an  arterial  circle  around 
the  base  of  the  heart,  while  the  other  passes  along  the  hne  of  union 
of  the  two  ventricles,  upon  the  anterior  aspect  of  the  heart  to  its 
apex,  where  it  anastomoses  with  the  descending  branch  of  the  right 
coronary.  It  supplies  the  left  auricle  and  the  adjoining  sides  of 
both  ventricles. 

The  right,  or  posterior  coronary  passes  forwards,  between  the  root 
of  the  pulmonary  artery  and  the  right  auricle,  and  winds  along  the 
auriculo-ventricular  groove,  to  the  posterior  median  furrow,  where 
it  descends  upon  the  posterior  aspect  of  the  heart  to  its  apex,  and 
inosculates  with  the  left  coronary.  It  is  distributed  to  the  right 
auricle  and  to  the  posterior  surface  of  both  ventricles,  and  sends  a 
large  branch  along  the  sharp  margin  of  the  right  ventricle  to  the 
apex  of  the  heart. 

ARTERIA     INNOMINATA. 

The  Arteria  innominata  (fig.  117,  No.  4,)  is  the  first  artery  given 
off  by  the  arch  of  the  aorta.     It  is  an  inch  and  a  half  in  length,  and 


292  COMMON  CAROTID  ARTERIES. 

ascends  obliquely  to  the  right  sterno-clavicular  articulation,  where 
it  divides  into  the  right  carotid  and  right  subclavian  artery. 

Relations. — It  is  in  relation,  in  front  with  the  left  vena  innomi- 
nata,  the  thymus  gland,  and  the  origins  of  the  sterno-thyroid  and 
sterno-hyoid  muscles,  which  separates  it  from  the  sternum.  Behind 
with  the  trachea,  pneumogastric  nerve  and  cardiac  nerves ;  exter- 
nally with  the  right  vena  innominata  and  pleura  ;  and  internally  with 
the  origin  of  the  left  carotid. 

Plan  of  the  relations  of  the  Arteria  Innominata. 

In  Front. 
Left  vena  innominata, 
Thymus  gland, 
Sterno-thyroid, 
Sterno-hyoid. 


Right  Side. 
Rig-ht  vena  innominata. 
Pleura. 


Arteria  innominata. 


Left  Side. 
Lefl  carotid. 


Behind. 
Trachea, 

Pneumogastric  nerve, 
Cardiac  nerves. 

The  arteria  innominata  occasionally  gives  off  a  small  branch 
which  ascends  along  the  middle  of  the  trachea  to  the  thyroid  gland. 
This  branch  was  described  by  Neubauer,  and  Dr.  Harrison  names 
it  the  middle  thyroid  artery.  A  knowledge  of  its  existence  is  ex- 
tremely important  in  performing  the  operation  of  tracheotomy. 

COMMON'     CAROTID    ARTERIES. 

The  common  carotid  arteries  (xapa,  the  head)  arise,  the  right  from 
the  bifurcation  of  the  arteria  innominata  opposite  the  right  sterno- 
clavicular articulation,  the  left  from  the  arch  of  the  aorta.  It  fol- 
lows, therefore,  that  the  right  carotid  is  shorter  than  the  left;  it  is 
also  more  anterior ;  and,  in  consequence  of  proceeding  from  a  branch 
instead  of  from  the  main  trunk,  it  is  larger  than  its  fellow. 

The  Right  common  carotid  artery  (fig.  117,  No.  5)  ascends  the 
neck  perpendicularly,  from  the  right  sterno-clavicular  articulation 
to  a  level  with  the  upper  border  of  the  thyroid  cartilage,  where  it 
<iivides  into  the  external  and  internal  carotid. 

The  Left  common  carotid  (fig.  117,  No.  11)  passes  somewhat  ob- 
liquely outwards  from  the  arch  of  the  aorta  to  the  side  of  the  neck, 
and  thence  upwards  to  a  level  with  the  upper  border  of  the  thyroid 
cartilage,  where  it  divides  like  the  right  common  carotid  into  the 
external  and  internal  carotid. 

Relations. — The  right  common  carotid  rests,  first  upon  the  longus 
colli  muscle,  then  upon  the  rectus  anticus  major,  the  sympathetic 
nerve  being  interposed.  The  inferior  thyroid  artery  and  recurrent 
laryngeal  nerve  pass  behind  it  at  its  lower  part.  To  its  inner  side 
is  the  trachea,  recurrent  laryngeal  nerve,  and  larynx;  io  hs  outer 
side,  and  enclosed  in  the  same  sheath,  the  jugular  vein  and  pneumo- 


EXTERNAL  CAROTID  ARTERY. 


293 


gastric  nerve;  and  in  front  the  sterno-thyroid,  sterno-hyoid,  sterno- 
mastoid,  omo-hyoid,  and  platysma  muscles,  and  the  descendens  noni 
nerve.  The  left  common  carotid,  in  addition  to  the  relations  just 
enumerated,  which  are  common  to  both,  is  crossed  near  its  com- 
mencement by  the  left  vena  innominata ;  it  lies  upon  the  trachea ; 
then  gets  to  its  side,  and  is  in  relation  with  the  oesophagus  and  tho- 
racic duct:  to  facilitate  the  study  of  these  relations,  I  have  arranged 
them  in  a  tabular  form. 

Plan  of  relations  of  the  Common  Carotid  Artery. 

In  Front, 

Platysma, 

Descendens  noni  nerve, 

Omo-hyoid, 

Sterno-mastoid, 

Sterno-hyoid, 

Sterno-thyroid. 


Externally. 
Internal  jugular  vein, 
Pneumogastric  nerve. 


Common 
Carotid  Artery. 


Internally. 
Trachea, 
Larynx, 

Recurrent  laryng 
nerve. 


Behind. 
Longus  colli, 
Rectus  anticus  major 
Sympathetic, 
Inferior  thyroid  artery, 
Recurrent  laryngeal  nerve. 

Additional  relations  of  the  Left  Common  Carotid. 


In  Front. 
Left  vena  innominata. 


Behind. 
Trachea, 
Thoracic  duct. 


Internally. 
Arteria  innominata, 
CEsophagus. 


Externally. 
Pleura. 


EXTERNAL     CAROTID     ARTERY. 

The  External  carotid  artery  ascends  nearly  perpendicularly  from 
opposite  the  upper  border  of  the  thyroid  cartilage,  to  the  space  be- 
tween the  neck  of  the  lower  jaw  and  the  meatus  auditorius,  where 
it  divides  into  the  temporal  and  internal  maxillary  artery. 

Relations. — In  front  it  is  crossed  by  the  posterior  belly  of  the 
digastricus,  stylo-hyoideus,  and  platysma  myoides  muscles ;  by  the 
lingual  nerve  near  its  origin ;  higher  up  it  is  situated  in  the  sub- 
stance of  the  parotid  gland,  and  is  crossed  by  the  facial  nerve.  Be- 
hind it  is  separated  from  the  internal  carotid  by  the  stylo-pharyngeus 
and  stylo-glossus  muscles,  glosso-pharyngeal  nerve,  and  part  of  the 
parotid  gland. 

25* 


294  SUPERIOR  THYROID  ARTERT. 

Plan  of  the  relations  of  the  External  Carotid  Artery. 

In  Front. 
Platysma, 
Digastricus, 
Stylo-hyoid, 
Lingual  nerve, 
Facial  nerve, 
Parotid  gland. 


External  Carotid  Artery. 


Behind. 
Stylo-pharyngeus, 
Stylo-glossus, 
Glosso-pharyngeal  nerve. 
Parotid  gland. 

Branches. — The  branches  of  the  external  carotid  are  eleven  in 
number,  and  may  be  arranged  into  four  groups,  viz. 

Anterior.  Posterior. 

1.  Superior  thyroid,  4.  Mastoid, 

2.  Lingual,  5.  Occipital, 

3.  Facial.  6.  Posterior  auricular. 

Superior.  Terminal. 

7.  Parotidean,  10.  Temporal, 

8.  Ascending  pharyngeal,  11.  Internal  maxillary. 

9.  Transverse  facial. 

The  anterior  branches  arise  from  the  commencement  of  the  exter- 
nal carotid,  within  a  short  distance  of  each  other.  The  lingual  and 
facial  bifurcate,  not  unfrequently,  from  a  common  trunk. 

1.  The  Superior  Thyroid  Artery  (the  first  of  the  branches  of 
theexternal  carotid)  curves  downwards  to  the  thyroid  gland  to  which 
it  is  distributed,  anastomosing  with  its  fellow  of  the  opposite  side, 
and  with  the  inferior  thyroid  arteries.  In  its  course  it  passes  be- 
neath the  omo-hyoid,  sterno-thyroid,  and  sterno-hyoid  muscle. 

Branches. 
Hyoid, 

Superior  laryngeal, 
Inferior  laryngeal, 
Muscular. 

The  Hyoid  branch  passes  forwards  beneath  the  thyro-hyoideus, 
and  is  distributed  to  the  insertion  of  the  depressor  muscles  into  the 
OS  hyoides. 

The  Superior  laryngeal  pierces  the  thyro-hyoidean  membrane,  in 
company  with  the  superior  laryngeal  nerve,  and  supplies  the  mucous 
membrane  and  muscles  of  the  larynx,  sending  a  branch  upwards  to 
the  epiglottis. 


LINGUAL  ARTERY. 


295 


The  In ferior  laryngeal  is  a  small  branch  which  crosses  the  crico- 
thyroidean  membrane  along  the  lower  border  of  the  thyroid  car- 
tilage. It  sends  branches  through  the  membrane  to  supply  the 
mucous  lining  of  the  larynx,  and  inosculates  with  its  fellow  of  the 
opposite  side. 

,     Fig.  118. 


The  muscular  branches  are  distributed  to  the  depressor  muscles 
of  the  OS  hyoides  and  larynx.  One  of  these  branches  crosses  the 
sheath  of  the  common  carotid  to  the  under  sui'face  of  the  sterno- 
mastoid  muscle. 

2.  The  Lingual  Arterv  ascends  obliquely  from  its  origin,  it  then 
passes  forwards  parallel  with  the  os  hyoides  ;  thirdly,  it  ascends  to 
the  under  surface  of  the  tongue ;  and  fourthly,  runs  forward  in  a 
serpentine  direction  to  its  tip,  under  the  name  of  ranine  artery, 
where  it  terminates  by  inosculating  with  its  fellow  of  the  opposite 
side. 

Relations. — l^he  first  part  of  its  course  rests  upon  the  middle  con- 
strictor muscle  of  the  pharynx,  being  covered  in  by  the  tendon  of 
the  digastricus  and  the  stylo-hyoid  muscle;  the  second  is  situated 
between  the  middle  constrictor  and  hyo-glossus  muscle,  the  latter 

Fig.  118.  The  carotid  arteries  with  the  branches  of  the  external  carotid.  1.  The 
common  carotid.  2.  The  external  carotid.  3.  The  internal  carotid.  4.  The  carotid 
foramen  in  the  petrous  portion  of  the  temporal  bone.  5.  The  superior  thyroid  artery. 
6.  The  lingual  artery.  7.  The  facial  artery.  8.  The  mastoid  artery.  9.  The  occi- 
pital. 10.  The  posterior  auricular.  11.  The  transverse  facial  artery.  12,  The  internal 
maxillary.     13.  The  temporal.     14.  The  ascending  pharyngeal  artery. 


296  FACIAL  ARTERY. 

separating  it  from  the  lingual  nerve;  in  the  thii^d  part  of  its  course 
it  lies  between  the  hyo-glossus  and  genio-hyo-glossus ;  and  in  the 
fourth  (ranine)  rests  upon  the  lingualis  to  the  tip  of  the  tongue. 

Branches. 

Hyoid,  • 

Dorsalis  linguae, 
Sublingual. 

The  Hyoid  branch  runs  along  the  upper  border  of  the  os  hyoides, 
and  is  distributed  to  the  origins  of  the  elevator  muscles  of  the  os 
hyoides,  inosculating  with  its  fellow  of  the  opposite  side. 

The  Dorsalis  linguce  ascends  along  the  posterior  border  of  the 
hyo-glossus  muscle  to  the  dorsum  of  the  tongue,  and  is  distributed 
to  the  tongue,  the  fauces  and  epiglottis,  anastomosing  with  its  fellow 
of  the  opposite  side. 

The  Sublingual  branch,  frequently  considered  as  a  branch  of 
bifurcation  of  the  lingual,  runs  along  the  anterior  border  of  the  hyo- 
glossus,  and  is  distributed  to  the  sublingual  gland  and  to  the  muscles 
of  the  tongue.  It  is  situated  between  the  mylo-hyoideus  and  genio- 
hyo-glossus,  generally  accompanies  Wharton's  duct  for  a  part  of 
its  course,  and  sends  a  branch  to  the  frcenum  linguae.  It  is  the 
latter  branch  which  affords  the  considerable  haemorrhage  which 
sometimes  accompanies  the  operation  of  snipping  the  frsenum  in 
children. 

3.  Facial  Artery. — The  Facial  artery  arises  a  little  above  the 
great  cornu  of  the  os  hyoides,  and  ascends  obliquely  to  the  submax- 
illary gland,  in  which  it  lies  embedded.  It  then  curves  around  the 
body  of  the  lower  jaw,  close  to  the  anterior  inferior  angle  of  the 
masseter  muscle,  ascends  to  the  angle  of  the  mouth,  and  thence  to 
the  angle  of  the  eye,  where  it  is_  named  the  angular  artery.  The 
facial  artery  is  very  tortuous  in  its  course  over  the  buccinator 
muscle,  to  accomodate  itself  to  the  movement  of  the  jaws. 

Relations. — Below  the  jaw  it  passes  beneath  the  digastricus  and 
stylo-hyoid  muscles  ;  on  the  body  of  the  lower  jaw  it  is  covered  by 
ihe  platysma  myoides,  and  at  the  angle  of  the  mouth  by  the  depressor 
anguli  oris  and  zygomatic  muscles.  It  rests  upon  the  submaxillary 
gland,  the  lower  jaw,  buccinator,  orbicularis  oris,  levator  anguli 
oris,  levator  labii  superioris  proprius,  and  levator  labii  superioris 
ala;que  nasi. 

Its  branches  are  divided  into  those  which  are  given  off  below  the 
jaw  and  those  on  the  face  :  they  may  be  thus  arranged: 

Below  the  Jaw. 

Inferior  palatine, 
Submaxillary, 
Submental, 
Pterygoid. 


FACIAL OCCIPITAL.  297 


On  the  Face. 


Masseteric, 
Inferior  labial, 
Inferior  coronary, 
Superior  coronary, 
Lateralis  nasi. 

The  Inferior  palatine  bi'anch  ascends  between  the  stylo-glossus 
and  stylo-pharyngeus  muscles,  to  be  distributed  to  the  tonsil  and 
soft  palate,  and  anastomoses  with  the  posterior  palatine  branch  of 
the  internal  maxillary  artery. 

The  Submaxillary  are  four  or  five  branches  which  supply  the 
submaxillary  gland. 

The  Submental  branch  runs  forwards  upon  the  mylo-hyoid  muscle, 
under  cover  of  the  body  of  the  lower  jaw,  and  anastomoses  with 
branches  of  the  sublingual  and  inferior  dental  artery. 

The  Pterygoid  branch  is  distributed  to  the  internal  pterygoid 
muscle. 

The  Masseteric  branches  are  distributed  to  the  masseter  and  buc- 
cinator muscles. 

The  Inferior  labial  branch  is  distributed  to  the  muscles  and  integu- 
ment of  the  lower  lip. 

The  Inferior  coronary  runs  along  the  edge  of  the  lower  lip, 
between  the  mucous  membrane  and  labial  glands,  and  the  orbicu- 
laris oris  ;  it  inosculates  with  the  corresponding  artery  of  the  oppo- 
site side. 

The  Superior  coronary  follows  the  same  course  along  the  upper 
lip,  inosculating  with  the  opposite  superior  coronary  artery,  and  at 
the  middle  of  the  lip  it  sends  a  branch  upwards  to  supply  the  septum 
of  the  nose  and  the  mucous  membrane. 

The  Lateralis  nasi  is  distributed  to  the  ala  and  septum  of  the 
nose. 

The  Inosculations  of  the  facial  artery  are  very  numerous :  thus 
it  anastomoses  with  the  sublingual  branch  of  the  lingual,  with  the 
ascending  pharyngeal  and  posterior  pafatine  arteries,  with  the  infe- 
rior dental  as  it  escapes  from  the  mental  foramen,  infra-orbital  at 
the  infra-orbital  foramen,  transverse  facial  on  the  side  of  the  face, 
and  at  the  angle  of  -the  eye  with  the  nasal  and  frontal  branches  of 
the  ophthalmic  artery. 

The  facial  artery  is  subject  to  considerable  varieties  in  its  extent ; 
it  not  unfrequently  terminates  at  the  angle  of  the  nose  or  mouth, 
and  is  rarely  symmetrical  on  both  sides  of  the  face. 

4.  The  Mastoid  Artery  turns  downwards,  to  be  distributed  to 
the  sterno-mastoid  muscle,  and  to  the  lymphatic  glands  of  the  neck; 
sometimes  it  is  replaced  by  two  small  branches. 

5.  The  Occipital  Artery,  smaller  than  the  preceding  branches, 
passes  backwards  beneath  the  posterior  belly  of  the  digastricus,  the 


298  POSTERIOR  AURICULAR — TEMPORAL. 

trachelo-mastoid  and  sterno-mastoid  muscles,  to  the  occipital  groove 
in  the  mastoid  portion  of  the  temporal  bone.  It  then  ascends 
between  the  splenitis  and  complexus  muscles,  and  divides  into  two 
branches,  which  are  distributed  upon  the  occiput,  anastomosing  with 
the  opposite  occipital,  the  posterior  auricular,  and  temporal  artery. 
The  lingual  nerve  curves  around  this  artery  near  to  its  origin  from 
the  external  carotid. 

Branches. — It  gives  off  only  two  branches  deserving  of  name, 
the  inferior  meningeal  and  princeps  cervicis. 

The  Inferior  meningeal  ascends  by  the  side  of  the  internal  jugular 
vein  and  passes  through  the  foramen  lacerum  posterius,  to  be  dis- 
tributed to  the  dura  mater. 

The  Arteria  princeps  ceroids  is  a  large  and  irregular  branch.  It 
descends  the  neck  between  the  complexus  and  semi-spinalis  colli, 
and  inosculates  with  the  profunda  cervicis  of  the  subclavian.  This 
branch  is  the  means  of  establishing  a  very  important  collateral  cir- 
culation between  the  branches  of  the  carotid  and  subclavian,  in 
ligature  of  the  common  carotid  artery. 

6.  The  Posterior  Auricular  Artery  arises  from  the  external 
carotid,  above  the  digastric  and  stylo-hyoid  muscles,  and  ascends 
beneath  the  lower  border  of  the  parotid  gland,  and  behind  the  concha, 
to  be  distributed  by  two  branches  to  the  external  ear  and  side  of  the 
head,  anastomosing  with  the  occipital  and  temporal  arteries;  some 
of  its  branches  pass  through  fissures  in  the  fibro-cartilage,  to  be 
distributed  to  the  anterior  surface  of  the  pinna.  The  anterior  auri- 
cular arteries  are  branches  of  the  temporal. 

Branches. — The  posterior  auricular  gives  off  but  one  named 
branch,  the  stylo-masioid ,  which  enters  the  stylo-mastoid  foramen  to 
be  distributed  to  the  aquseductus  Fallopii  and  tympanum. 

7.  The  Parotidean  Arteries  are  four  or  five  large  branches 
which  are  given  off  from  the  external  carotid  whilst  that  vessel  is 
situated  in  the  parotid  gland.  They  are  distributed  to  the  structure 
of  the  gland,  their  terminal  branches  reaching  the  integument  and 
the  side  of  the  face. 

8.  The  Ascending  Pharyngeal  Artery,  the  smallest  of  the 
branches  of  the  external  carotid,  arises  from  that  trunk  near  to  its 
bifurcation,  and  ascends  between  the  internal  carotid  and  the  side  of 
the  pharynx  to  the  base  of  the  skull,  where  it  divides  into  two 
branches ;  meningeal,  which  enters  the  foramen  lacerum  posterius, 
to  be  distributed  to  the  dura  mater  ;  and  pharyngeal.  It  supplies 
the  pharynx,  tonsils,  and  Eustachian  tube. 

9.  The  Transvkksalis  Faciei  arises  from  the  external  carotid 
whilst  that  trunk  is  lodged  within  the  parotid  gland  ;  it  crosses  the 
masseter  muscle,  lying  parallel  with  and  a  little  above  Stcnon's  duct; 
and  is  distributed  to  the  temporo-maxillary  articulation,  and  to  the 
muscles  and  integument  on  the  side  of  the  face,  inosculating  with 
the  infra-orbital  and  facial  artery.  This  artery  is  not  unfrequently 
a  branch  of  the  temporal. 


INTERNAL  MAXILLARV  ARTERY.  299 

10.  The  Temporal  Artery  is  one  of  the  two  terminal  branches 
of  the  external  carotid.  It  ascends  over  the  root  of  the  zygoma ; 
and  at  about  an  inch  and  a  half  above  the  zygomatic  arch,  divides 
into  an  anterior  and  a  posterior  temporal  branch.  The  anterior 
temporal  is  distributed  over  the  front  of  the  temple  and  arch  of  the 
skull,  and  anastomoses  with  the  opposite  anterior  temporal,  and  with 
the  supra-orbital  and  frontal  artery.  The  posterior  temporal  curves 
upwards  and  backwards,  and  inosculates  with  its  fellow  of  the  oppo- 
site side,  with  the  posterior  auricular  and  occipital  artery. 

The  trunk  of  the  temporal  arter}'  is  covered  in  by  the  parotid 
gland  and  by  the  attrahens  aurem  muscle,  and  rests  upon  the  tem- 
poral fascia. 

Branches. 

Orbitar, 

Anterior  auricular, 

Middle  temporal. 

The  Orbitar  arterTj  is  a  small  branch,  not  always  present,  which 
passes  forwards  immediately  above  the  zygoma,  between  the  two 
layers  of  the  temporal  fascia,  and  inosculates  beneath  the  orbicularis 
palpebrarum  wath  the  palpebral  arteries. 

The  Anterior  auricular  arteries  are  distributed  to  the  anterior  por- 
tion of  the  pinna. 

The  Middle  temporal  branch  passes  through  an  opening  in  the 
temporal  fascia  immediately  above  the  zygoma,  and  supplies  the 
temporal  muscle  inosculating  with  the  deep  temporal  arteries, 

11.  The  Internal  Maxillary  Artery,  the  other  terminal  branch 
of  the  external  carotid,  has  next  to  be  examined. 

Dissection. — The  Internal  maxillary  o-^'^er?/ passes  inwards  behind 
the  neck  of  the  lower  jaw  to  the  deep  structures  in  the  face ;  we 
require,  therefore,  to  remove  several  parts  for  the  purpose  of  seeing 
it  completely.  To  obtain  a  good  view  of  the  vessel,  the  zygoma 
should  be  sawn  across  in  front  of  the  external  ear,  and  the  malar 
bone  near  to  the  orbit.  Turn  down  the  zygomatic  arch  with  the 
masseter  muscle.  In  doing  this,  a  small  artery  and  nerve  will  be 
seen  crossing  the  sigmoid  arch  of  the  lower  jaw,  and  entering  the 
masseter  muscle  (the  masseteric).  Cut  away  the  tendon  of  the  tem- 
poral muscle  from  its  insertion  into  the  coronoid  process,  and  turn  it 
upwards  towards  its  origin  ;  some  vessels  will  be  seen  entering  its 
under  surface;  these  are  the  deep  tempojril.  Then  saw  the  ramus 
of  the  jaw  across  its  middle,  and  dislocate  it  from  its  articulation 
with  the  temporal  bone.  Be  careful  in  doing  this  to  carry  the  blade 
of  the  knife  close  to  the  bone,  lest  any  branches  of  nerves  should 
be  injured.  Next  raise  this  portion  of  bone,  and  with  it  the  external 
pterygoid  njuscle.  The  artery,  together  with  the  deep  branches  of 
the  inferior  maxillary  nerve,  will  be  seen  lying  upon  the  pterygoid 


300 


INTERNAL  MAXILLARY  ARTERY. 


muscles.     These  are  to  be  carefully  freed  of  fat  and  cellular  tissue, 
and  then  examined. 

This  artery  (118,  12;  and  119)  commences  in  the  substance  of  the 
parotid  gland,  opposite  the  meatus  auditorius  externus,  it  passes  in 
the  first  instance  horizontally  forwards  behind  the  neck  of  the  lower 
jaw ;  next,  curves  around  the  lower  border  of  the  external  pterygoid 
muscle  near  its  origin,  and  ascends  obliquely  forwards  upon  the 
outer  side  of  that  muscle;  it  then  passes  between  the  two  heads  of 
the  external  pterygoid  and  enters  the  pterygo-maxillary  fossa.  Occa- 
sionally it  passes  between  the  two  pterygoid  muscles,  without  appear- 
ing on  the  outer  surface  of  the  external  pterygoid.  In  consideration 
of  its  course  this  artery  may  be  divided  into  three  portions;  maxil- 
lary, pterygoid,  and  pterygo-maxillary. 

Fig.  119. 


Relations. — The  Maxillary  portion  is  situated  between  the  ramus 
of  the  jaw  and  the  internal  lateral  ligament,  lying  parallel  with  the 
auricular  nerve;  \\\e pterygoid  ^^ovhon  between  the  external  ptery- 
goid muscle,  and  the  masseter  and  temporal  muscle.  The  pterygo- 
maxillary  portion  lies  between  the  two  heads  of  the  external  ptery- 


Fig.  119.  ].  The  external  carotid  artery.  2.  The  trunk  of  the  transverse  facial 
artery.  3,  4.  Tlie  two  terminal  branches  of  the  external  carotid.  3.  The  temporal 
artery;  and  4.  The  internal  maxillary,  the  first  or  maxiUary  portion  of  its  course: 
the  limit  of  this  portion  is  marked  by  an  arrow.  5.  The  second,  or  plerygoid  portion, 
of  the  artery;  the  limits  are  bounded  by  the  arrows.  6.  The  third  or  jilerysromaxil- 
lory  portion.  The  branches  of  the  maxillary  portion  arc,  7.  A  tynipnnic  branch. 
8.  The  artcria  mening-ca  magna.  9.  The  artcria  meningea  parva.  10.  The  infe- 
rior dental  artery.  The  branches  of  the  second  portion  are  wholly  muscular,  the 
ascending  ones  being  distributed  to  the  temporal,  and  the  descending  to  the  four  other 
muscles  of  the  inter-maxillary  region,  viz.  tlie  two  pterygoids,  the  masseter  and  buc- 
cinator. The  branches  of  the  pterygo-maxillary  portion  of  the  artery  are,  11.  The 
sujjerior  dental  artery.  12.  Tlic  infra-orbit:il  arlery.  13.  The  posterior  palatine.  14. 
The  splieno-palatine  or  nasal.  1.5.  '["he  ptcrygo-piilatinc.  IC.  The  Vidian.  *  The 
remarkable  bend  which  the  third  portion  of  the  aitery  makes  as  it  turns  inwards  to 
enter  the  pterygo-maxillary  fossa. 


INTERNAL  MAXILLARY  ARTERY.  301 

gold  muscle,  and  in  the  spheno-maxillary  fossa  is  in  relation  with 
Meckel's  ganglion. 

Branches. 

/'  Tympanic, 
*        ,.     .„  ^.  1  Inferior  dental, 

Muxillary  portion       2  ^^^^^.^  meningea  magna, 

^  Arteria  meningea  parva. 

^  Deep  temporal  branches, 
N  External  pterygoid, 
Pterygoid  portion       n  Internal  pterygoid, 
/  Masseteric, 

V  Buccal. 

X  Superior  dental, 
I  Infra-orbital, 
Ptery go-maxillary     J  Pterygo-palatine, 
portion  S  Spheno-palatine, 

/  Posterior  palatine, 

V  Vidian. 

The  Tympanic  branch  is  small  and  not  likely  to  be  seen  in  an 
ordinary  dissection  ;  it  is  distributed  to  thetemporo-maxillary  articu- 
lation and  meatus,  and  passes  into  the  tympanum  through  the  fissura 
Glaseri. 

The  Inferior  dental  descends  to  the  dental  foramen,  and  enters 
the  canal  of  the  lower  jaw  in  company  with  the  dental  nerve. 
Opposite  the  bicuspid  teeth  it  divides  into  two  branches,  one  of 
which  is  continued  onwards  within  the  bone  as  far  as  the  symphysis, 
to  supply  the  incisor  teeth,  while  the  other  escapes  with  the  nerve 
at  the  mental  foramen,  and  anastomoses  with  the  inferior  labial  and 
submental  branch  of  the  facial.  It  supplies  the  teeth  of  the  lower 
jaw,  sending  small  branches  along  the  canals  in  their  roots. 

The  Arteria  meningea  magna  ascends  behind  the  temporo-maxil- 
lary  articulation  to  the  foramen  spinosum  in  the  spinous  process  of 
the  sphenoid  bone,  and  entering  the  cranium  divides  into  an  anterior 
and  a  posterior  branch.  The  anterior  branch  crosses  the  great  ala 
of  the  sphenoid  to  the  groove  or  canal  in  the  anterior  inferior  angle 
of  the  parietal  bone,  and  divides  into  branches,  which  ramify  upon 
the  external  surface  of  the  dura  mater,  and  anastomose  with  the 
corresponding  branches  from  the  opposite  side.  The  posterior 
branch  crosses  the  squamous  portion  of  the  temporal  bone,  to  the 
posterior  part  of  the  dura  mater  and  cranium.  The  branches  of  the 
arteria  meningea  magna  are  distributed  chiefly  to  the  bones  of  the 
skull;  and  in  the  middle  fossa  it  sends  a  small  branch  through  the 
hiatus  Fallopii  to  the  facial  nerve. 

The  Meningea  parva  is  a  small  branch  which  ascends  to  the 
foramen  ovale,  and  passes  into  the  skull  to  be  distributed  to  the 

26 


302  INTERNAL  CAROTID  ARTERY. 

Casserian  ganglion  and  dura  mater.  It  gives  off  a  small  branch  to 
the  nasal  foss®  and  soft  palate. 

The  Muscular  branches  are  distributed,  as  their  names  imply,  to 
the  five  muscles  of  the  maxillary  region;  the  temporal  branches  are 
two  in  number. 

The  Superior  dental  artery  is  given  off  from  the  internal  maxil- 
lary, just  as  that  vessel  is  about  to  make  its  turn  into  the  spheno- 
maxillary fossa.  It  descends  upon  the  tuberosity  of  the  superior 
maxillary  bone,  and  sends  its  branches  through  several  small  fora- 
mina to  supply  the  posterior  teeth  of  the  upper  jaw,  and  the  antrum. 
The  terminal  branches  .are  continued  forwards  upon  the  alveolar 
process,  to  be  distributed  to  the  gums  and  to  the  sockets  of  the 
teeth. 

The  Infra-orhital  would  appear,  from  its  size,  to  be  the  proper 
continuation  of  the  artery.  It  runs  along  the  infra-orbital  canal 
with  the  superior  maxillary  nerve,  sending  branches  into  the  orbit 
and  downwards  through  canals  in  the  bone,  to  supply  the  mucous 
lining  of  the  antrum  and  the  teeth  of  the  upper  jaw,  and  escapes 
from  the  infra-orbital  foramen.  The  branch  which  supplies  the  in- 
cisor teeth  is  the  anterior  dental  artery ;  on  the  face  it  inosculates 
with  the  facial  and  transverse  facial  arteries. 

The  Ptery go-palatine  is  a  small  branch  which  passes  through  the 
pterygo-palatine  canal,  and  supplies  the  upper  part  of  the  pharynx 
and  Eustachian  tube. 

The  Spheno-palatine,  or  nasal,  enters  the  superior  meatus  of  the 
nose  through  the  spheno-palatine  foramen  in  company  with  the 
nasal  branches  of  Meckel's  ganglion,  and  divides  into  two  branches ; 
one  of  which  is  distributed  in  the  mucous  membrane  of  the  septum ; 
while  the  other  supplies  the  mucous  membrane  of  the  lateral  wall 
of  the  nares,  together  with  the  sphenoid  and  ethmoid  cells. 

The  Posterior  palatine  artery  descends  along  the  posterior  pala- 
tine canal,  in  company  with  the  posterior  palatine  branches  of 
Meckel's  ganglion,  to  the  posterior  palatine  foramen ;  it  then  curves 
forwards  lying  in  a  groove  upon  the  bone,  and  is  distributed  to  the 
palate,  while  in  the  posterior  palatine  canal  it  sends  a  small  branch 
backwards,  through  the  small  posterior  palatine  foramen  to  supply 
the  soft  palate,  and  anteriorly  it  supplies  a  branch  to  the  anterior 
palatine  canal,  which  reaches  the  nares  and  inosculates  with  the 
branches  of  the  spheno-palatine  artery. 

The  Vidian  branch  passes  backwards  along  the  pterygoid  canal, 
and  is  distributed  to  the  sheath  of  the  Vidian  nerve,  and  to  the 
Eustachian  tube. 

INTERNAL     CAROTID     ARTERV. 

The  internal  carotid  artery  curves  slightly  outwards  from  the 
bifurcation  of  the  common  carotid,  and  then  ascends  nearly  perpen- 
dicularly through  the  maxillo-pharyngcal  space*  to  the  carotid  fora 
men  in  the  petrous  bone.     It  next  passes  inwards  along  the  carotid 

*  For  the  boundaries  of  this  space  see  page  189. 


INTERNAL  CAROTID  ABTERY. 


303 


C2ind.\,  forwards  by  the  side  of  the  sella  turcica,  and  upwards  by  the 
anterior  clinoid  process,  where  it  pierces  the  dura  mater  and  divides 
into  three  terminal  branches.  The  course  of  this  artery  is  remark- 
able from  the  number  of  angular  curves  which  it  forms ;  one  or 
two  of  these  flexures  are  sometimes  seen  in  the  cervical  portion  of 
the  vessel  near  to  the  base  of  the  skull ;  and  by  the  side  of  the  sella 
turcica  it  resembles  the  italic  letter  s,  placed  horizontally. 

Relations. — In  consideration  of  its  connexions,  the  artery  is  divi- 
sible into  a  cervical,  petrous,  cavernous  and  cerebral  portion.  The 
Cervical  portion  is  in  relation  posteriorly  wiih  the  rectus  anticus 
major,  sympathetic  nerve,  pharyngeal  and  laryngeal  nerves  which 
cross  behind  it,  and  near  the  carotid  foramen  with  the  glosso- 
pharyngeal, pneumogastric  and  lingual  nerves,  and  partially  with 
the  internal  jugular  vein.  Internally  it  is  in  relation  with  the  side 
of  the  pharynx,  the  tonsil,  and  the  ascending  pharyngeal  artery. 
Externally  with  the  internal  jugular  vein,  glosso-pharyngeal,  pneu- 
mogastric and  lingual  nerves,  and  in  front  with  the  stylo-glossus, 
and  stylo-pharyngeus  muscle,  glosso-pharyngeal  nerve,  and  parotid 
gland. 

Plan  of  the  relations  of  the  cervical  portion  of  the  internal  carotid 
artery. 

In  Front. 
Parotid  gland, 
Stylo-g^lopsus  muscle, 
Stylo-pharyngeus  muscle, 
Glosso-pharyngeal  nerve. 


Internally. 

Pharynx, 
Tonsil, 

Ascending  pharyn- 
geal artery. 


Internal 
Carotid  Artery. 


Externally. 
Jngnlar  vein, 
Glosso-pharyngeal, 
Pneumogastric, 
Lingual  nerve. 


Behind. 
Superficial  cervical  ganglion, 
Pneumogastric  nerve, 
Glosso-pharyngeal, 
Pharyngeal  nerve, 
Superior  laryngeal  nerve, 
Sympathetic  nerve, 
Rectus  anticus  major. 

The  Petrous  portion  is  separated  from  the  bony  wall  of  the 
carotid  canal  by  a  lining  of  dura  mater;  it  is  in  relation  with  the 
carotid  plexus,  and  is  covered  in  by  the  Casserian  ganglion. 

The  Cavernous  portion  is  situated  on  the  inner  wall  of  the  caver- 
nous sinus,  and  is  in  relation  by  its  outer  side  with  the  lining  mem- 
brane of  the  sinus,  the  sixth  nerve,  and  the  ascending  branches  of 
the  carotid  plexus.  The  third,  fourth,  and  ophthalmic  nerves  are 
placed  in  the  outer  wall  of  the  cavernous  sinus,  and  are  separated 
from  the  artery  by  the  lining  membrane  of  the  sinus. 

The  Cerebral  portion  of  the  artery  is  enclosed  in  a  sheath  of  the 
arachnoid,  and  is  in  relation  with  the  optic  nerve.  At  its  point  of 
division  it  is  situated  in  the  fissure  of  Sylvius. 


304  OPHTHALMIC  AETEET. 

Branches. — The  cervical  portion  of  the  internal  carotid  gives  off 
no  branches :  from  the  other  portions  are  derived  the  following : 

Tympanic, 

Anterior  meningeal. 

Ophthalmic, 

Anterior  cerebral, 

Middle  cerebral, 

Posterior  communicating, 

Choroidean. 

The  Tt/mpanic  is  a  small  branch  which  enters  the  tympanum 
through  a  minute  foramen  in  the  carotid  canal. 

The  interior  meningeal  is  distributed  to  the  dura  mater  and  Cas- 
serian  ganglion. 

The  Ophthalmic  artery  arises  from  the  cerebral  portion  of  the  in- 
ternal carotid,  and  enters  the  orbit  through  the  foramen  opticum, 
immediately  to  the  outer  side  of  the  optic  nerve.  It  then  crosses 
the  optic  nerve  to  the  inner  wall  of  the  orbit,  and  runs  along  the 
lower  border  of  the  superior  oblique  muscle,  to  the  inner  angle  of 
the  eye,  where  it  divides  into  two  terminal  branches,  the  frontal  and 
nasal. 

Branches. — The  branches  of  the  ophthalmic  artery  may  be 
arranged  into  two  groups : — first,  those  distributed  to  the  orbit  and 
surrounding  parts ;  and  secondly,  those  which  supply  the  muscles 
and  globe  of  the  eye.     They  are — 

First  group.  Second  group. 

Lachrymal,  Muscular, 

Supra-orbital,  Anterior  ciliary, 

Posterior  ethmoidal,  Ciliary  short  and  long, 

Anterior  ethmoidal,  Centralis  retinae. 

Palpebral, 
Frontal, 
Nasal. 

The  Lachrymal  is  the  first  branch  of  the  ophthalmic  artery,  and 
is  usually  given  off  immediately  before  that  artery  enters  the  optic 
foramen.  It  follows  the  course  of  the  lachrymal  nerve,  along  the 
upper  border  of  the  external  rectus  muscle,  and  is  distributed  to  the 
lachrymal  gland.  The  small  branches  which  escape  from  the  gland 
supply  the  conjunctiva  and  upper  eyelid.  The  lachrymal  artery 
gives  off  a  malar  branch  which  passes  through  the  malar  bone  into 
the  temporal  fossa  and  inosculates  with  the  deep  temporal  arteries, 
while  some  of  its  branches  become  subcutaneous  on  the  cheek  and 
anastomose  with  the  transverse  facial. 

The  Supra-orbital  artery  follows  the  course  of  the  frontal  nerve, 
resting  on  the  levator  palpcbra;  muscle:  it  passes  through  the  supra- 
orbital foramen,  and  divides  into  a  superficial  and  deep  branch  which 
arc  distributed  to  the  muscles  and  integument  of  the  forehead  and 
to  the  pericranium.  At  the  supra-orbital  foramen  it  sends  a  branch 
inwards  to  the  diploe. 


OPHTHALMIC  ARTERY.  305 

The  Ethmoidal  arteries,  'posterior  and  anterior,  pass  through  the 
ethmoidal  foramina,  and  are  distributed  to  the  falx  cerebri  and  to 
the  ethmoidal  cells  and  nasal  fossae.  The  latter  accompanies  the 
nasal  nerve. 

The  Palpebral  arteries,  superior  and  inferior,  are  given  off  from 
the  ophthalmic,  near  to  the  inner  angle  of  the  orbit ;  they  encircle 
the  eyelids,  forming  a  superior  and  inferior  arch  near  to  the  borders 
of  the  lids,  between  the  orbicularis  palpebrarum  and  tarsal  cartilage. 
At  the  outer  angle  of  the  eyelids  the  superior  palpebral  inosculates 
with  the  orbital  branch  of  the  temporal  artery.  The  inferior  palpe- 
bral artery  sends  a  branch  to  the  nasal  duct. 

The  Frontal  artery,  one  of  the  terminal  branches  of  the  ophthalmic, 
emerges  from  the  orbit  at  its  inner  angle,  and  ascends  along  the 
middle  of  the  forehead.  It  is  distributed  to  the  integument,  muscles, 
and  pericranium. 

The  Nasal  artery,  the  other  terminal  branch  of  the  ophthalmic, 
passes  out  of  the  orbit  above  the  tendo  oculi,  and  divides  into  two 
branches ;  one  of  which  inosculates  with  the  angular  artery,  while 
the  other,  the  dorsalis  nasi,  runs  along  the  ridge  of  the  nose  and  is 
distributed  to  its  entire  surface.  The  nasal  artery  sends  a  small 
branch  to  the  lachrymal  sac. 

The  Muscular  branches,  usually  two  in  number,  superior  and 
inferior,  supply  the  muscles  of  the  orbit ;  and  upon  the  anterior 
aspect  of  the  globe  of  the  eye  give  off  the  anterior  ciliary  arteries, 
which  pierce  the  sclerotic  near  its  margin  of  connexion  with  the 
cornea,  and  are  distributed  to  the  iris.  It  is  the  congestion  of  these 
vessels  that  gives  rise  to  the  vascular  zone  around  the  cornea  in  iritis. 

The  Ciliary  arteries  are  divisible  into  three  groups, — short,  long, 
and  anterior. 

The  Short  ciliary  are  very  numerous ;  they  pierce  the  sclerotic 
around  the  entrance  of  the  optic  nerve,  and  supply  the  choroid  coat 
and  ciliary  processes.  The  long  ciliary,  two  in  number,  pierce  the 
sclerotic  upon  opposite  sides  of  the  globe  of  the  eye,  and  pass  for- 
wards between  it  and  the  choroid  to  the  iris.  They  form  an  arterial 
circle  around  the  circumference  of  the  iris  by  inosculating  with 
each  other,  and  from  this  circle  branches  are  given  off  which  ramify 
in  the  substance  of  the  iris,  and  form  a  second  circle  around  the 
pupil.  The  anterior  ciliary  are  branches  of  the  muscular  arteries ; 
they  terminate  in  the  great  arterial  circle  of  the  iris. 

The  Centralis  retince  artery  pierces  the  optic  nerve  obliquely, 
and  passes  forwards  in  the  centre  of  its  cylinder  to  the  retina, 
where  it  divides  into  branches,  which  ramify  in  the  inner  layer  of 
that  membrane.  It  supplies  the  retina,  hyaloid  membrane,  and 
zonula  ciliaris ;  and,  by  means  of  a  branch  sent  forwards  through 
the  centre  of  the  vitreous  humour  in  a  tubular  sheath  of  the  hyaloid 
membrane,  the  capsule  of  the  lens. 

The  Anterior  cerebral  artery  passes  forwards  in  the  great  longi- 
tudinal fissure  between  the  two  hemispheres  of  the  brain;  then 
curves  backwards  along  the  corpus  callosum  to  its  posterior  exlre- 

26* 


306  SUBCLAVIAN  AKTERY. 

mity.  It  gives  branches  to  the  olfactory  and  optic  nerves,  to  the 
under  surface  of  the  anterior  lobes,  the  third  ventricle,  the  corpus 
callosum,  and  the  inner  surface  of  the  hemispheres.  The  two  ante- 
rior cerebral  arteries  are  connected  soon  after  their  origin  by  a 
short  anastomosing  trunk,  the  anterior  communicativg. 

The  Middle  cerebral  arie?-?/,  larger  than  the  preceding,  passes  out- 
wards along  the  fissure  of  Sylvius,  and  divides  into  three  principal 
branches,  which  supply  the  anterior  and  middle  lobes,  and  the  island 
of  Reil.  Near  to  its  origin  it  gives  off  the  numerous  small  branches 
which  enter  the  substantia  perforata  to  be  distributed  to  the  corpus 
striatum. 

The  Posterior  communicating  artery,  very  variable  in  size,  some- 
times double,  and  sometimes  altogether  absent,  passes  backwards 
and  inosculates  with  the  posterior  cerebral,  a  branch  of  the  basilar 
artery.  Occasionally  it  is  so  large  as  to  take  the  place  of  the  pos- 
terior cerebral  artery. 

The  Choroidean  is  a  small  branch  which  is  given  off  from  the 
internal  carotid,  near  to  the  origin  of  the  posterior  communicating 
artery,  and  passes  beneath  the  edge  of  the  middle  lobe  of  the  brain 
to  enter  the  descending  cornu  of  the  lateral  ventricle.  It  is  distri- 
buted to  the  choroid  plexus,  and  to  the  walls  of  the  middle  cornu. 

SUBCLAVIAN     ARTERY. 

The  Subclavian  artery,  on  the  right  side,  arises  from  the  arteria 
innominata,  opposite  the  sterno-clavicular  articulation,  and  on  the 
left,  from  the  arch  of  the  aorta.  The  right  is  consequently  shorter 
than  the  left,  and  is  situated  nearer  to  the  anterior  wall  of  the  chest; 
it  is  also  somewhat  greater  in  diameter,  from  being  a  branch  of  a 
branch,  in  place  of  a  division  from  the  main  trunk. 

The  course  of  the  subclavian  artery  is  divisible,  for  the  sake  of 
precision  and  surgical  observation,  into  three  portions.  The  first 
portions  of  the  right  and  left  arteries  differ  in  their  course  and  rela- 
tions in  correspondence  with  their  dissimilarity  of  origin.  The  other 
two  portions  are  precisely  alike  on  both  sides. 

The  first  portion,  on  the  right  side,  ascends  obliquely  outwards  to 
the  inner  border  of  the  scalenus  anticus.  On  the  left  side  it  ascends 
perpendicularly  to  the  inner  border  of  that  muscle.  The  second 
portion  curves  outwards  behind  the  scalenus  anticus  ;  and  the  third 
portion  passes  dov^^nwards  and  outwards  beneath  the  clavicle,  to  the 
lower  border  of  the  first  rib,  where  it  becomes  the  axillary  artery. 

Relations. — The  first  portion,  on  the  right  side,  is  in  relation  in 
front  with  the  internal  jugular  and  subclavian  vein  at  their  point  of 
junction,  and  is  crossed  by  the  pneumogastric  nerve,  cardiac  nerves, 
and  phrenic  nerve.  Behind  and  beneath  it  is  invested  by  the  pleura, 
is  crossed  by  the  right  recurrent  laryngeal  nerve  and  vertebral  vein, 
and  is  in  relation  with  the  transverse  process  of  the  seventh  cervical 
vertebra.  The  first  portion  on  the  left  side  is  in  relation  in  front 
with  the  pleura,  the  vena  innominata,  the  pneumogastric  and  phrenic 
nerves  (which  lie  parallel  to  it),  and  the  left  carotid  artery.     To  its 


SXIBCliAVIAN  ARTERY RELATIONS. 


307 


inner  side  is  the  ojsophagus ;  to  its  outer  side  the  pleura ;  and  behind, 
the  thoracic  duct,  longus  colli,  and  vertebral  column. 

Plan  of  the  relations  of  ihe  first  portion  of  the  Right  Subclavian  Artery. 

In  Front. 
Internal  jugular  vein, 
Subclavian  vein, 
Pneumogastric  nerve. 
Cardiac  nerves. 
Phrenic  nerve. 


Rjght  Subclavian  Artery. 


Behind  and  beneath. 
Pleura, 

Recurrent  laryngeal  nerve, 
Vertebral  vein, 
Transverse  process  of  the  7th  cervical  vertebra 

Plan  Qf  the  relations  of  the  fii'st  portion  of  the  Left  Subclavian  Artery. 

In  Front. 
Pleura, 

Vena  innominata, 
Pneumogastric  nerve, 
Phrenic  nerve. 
Left  carotid. 


Inner  Side. 
CEsophagus. 


Left  Subclavian  Artery. 


Outer  Side. 
P  leura. 


*  Behind. 

Thoracic  duct, 
Longus  colli, 
Vertebral  column. 

The  Second  portion  is  situated  between  the  two  scaleni,  and  is 
supported  by  the  margin  of  the  first  rib.  The  scalenus  anticus 
separates  it  from  the  subclavian  vein  and  phrenic  nerve.  Behind  it 
is  in  relation  with  the  brachial  plexus. 

The  Thyroid  forti on  is  in  relation,  zw_/ro7?i  with  the  subclavian 
vein  and  subclavius  muscle  ;  behind  with  the  brachial  plexus  and 
scalenus  posticus ;  below  with  the  first  rib ;  and  aboi^e  with  the  supra- 
scapular artery  and  platysma. 

Plan  of  the  relations  of  the  third  portion  of  the  Subclavian  Artery. 

Above. 
Supra-scapular  artery, 
Platysma  myoides. 


In  Front. 
Subclavian  vein, 
Subclavius. 


Subclavian  Artery, 
Third  portion. 


Behind. 
Brachial  plexus. 
Scalenus  posticus. 


Below. 
First  rib. 


Branches. — The  greater  part  of  the  branches  of  the  subclavian 
are  given  off  from  the  artery  before  it  arrives  at  the  margin  of  the 


308 


VERTEBRAL  ARTERY. 


first  rib.  The  profunda  cervicis  and  superior  intercostal  frequently 
encroach  upon  the  second  portion,  and  not  unfrequently  a  branch  or 
branches  may  be  found  proceeding  from  the  third  portion. 

The  primary  branches  are  five  in  number,  the  three  first  being 
ascending,  and  the  latter  descending ;  they  are  the — 
Vertebral, 


Thyroid  axis, 


Inferior  thyroid, 
Supra-scapular,* 
Posterior  scapular, 
Superficialis  cervicis. 


Fig.  120. 


Profunda  cervicis, 
Superior  intercostal, 
Internal  mammary. 

The  Vertebral  Artery  is  the  first  and  the  largest  of  the 
branches  of  the  subclavian  artery  ;  it  ascends  through  the  foramina 
in  the  transverse  processes  of  all  the  cervical  vertebrae,  excepting 
the  last ;  then  winds  backwards  around  the  articulating  process  of 
the  atlas  ;  and  piercing  the  dura  mater  enters  the  skull  through  the 
foramen  magnum.  The  two  arteries  unite  at  the  lower  border  of 
the  pons  Varolii,  to  form  the  basilar  artery.  In  the  foramina  of 
the  transverse  processes  of  the  vertebras  the  artery  lies  in  front  of 
the  cervical  nerves. 

Dr.  John  Davyj-  has  observed  that,  when  the  vertebral  arteries 

differ  in  size,  the  left  is  generally  the 
larger:  thus  in  ninety-eight  cases  he 
found  the  left  vertebral  the  larger 
twenty-six  times,  and  the  right  only 
eight.  In  the  same  number  of  cases  he 
found  a  small  band  stretching  across 
the  cylinder  of  the  basilar  artery,  near 
the  junction  of  the  two  vertebral  arte- 
ries, seventeen  times,  and  in  a  few  in- 
stances a  small  communicating  trunk 
between  the  two  vertebral  arteries  pre- 
viously to  their  union.  I  have  several 
times  seen  this  communicating  branch, 
and  have  a  preparation  now  before  me 
in  which  it  is  exhibited. 

The  Basilar  Artery,  so  named  from 
its  position  at  the  base  of  the  brain, 
runs  forwards  to  the  anterior  border  of  the  pons  Varolii,  where  it 
divides  into  four  ultimate  branches,  two  to  either  side. 

Fig-.  120.  The  brandies  of  the  riglit  subclavian  artery.  1.  The  artcria  innominata. 
2.  The  right  carotid.  3.  Tlic  first  portion  of  the  subclavian  artery.  4.  The  second 
portion.  5.  The  third  portion.  6.  The  vertebral  artery.  7.  The  inferior  thyroid.  8. 
The  thyroid  axis.  9.  The  superficialis  cervicis.  10.  The  profunda  cervicis.  11.  The 
posterior  scapular  or  transvcrsalis  colli.  12.  The  supra-scapular.  13.  Tlie  internal 
mammary  artery.     14.  The  superior  intcrcostnl. 

*  TluH  is  usually  dcseiibed  ;is  arising  from  the  axillary,  but  I  have  most  frequently 
found  it  to  arise  from  the  subclavian. — G. 

t  Edinburgh  Medical  and  Surgical  Journal,  1839. 


BASILAR  ARTERY BRANCHES.  309 

Branches. — The  branches  of  the  vertebral  and  basilar  arteries 
are  the  following : 

''  Lateral  spinal, 
Posterior  meningeal, 
Vertebral,  <    Anterior  spinal, 
I   Posterior  spinal, 
1^  Inferior  cerebellar. 
[  Transverse, 
Basilar,     <  Superior  cerebellar, 
(  Posterior  cerebral. 

The  Lateral  spinal  branches  enter  the  intervertebral  foramina, 
and  are  distributed  to  the  spinal  cord  and  to  its  membranes.  Where 
the  vertebral  artery  curves  around  the  articular  process  of  the  atlas, 
it  gives  off  several  muscular  branches. 

The  Posterior  meningeal  are  one  or  two  small  branches,  which 
enter  the  cranium  through  the  foramen  magnum,  to  be  distributed 
to  the  dura  mater  of  the  cerebellar  fossae,  and  to  the  falx  cerebelli. 
One  branch,  described  by  Soemmering,  passes  into  the  cranium 
along  the  first  cervical  nerve. 

The  Anterior  spinal  is  a  small  branch  which  unites  with  its 
fellow  of  the  opposite  side,  on  the  front  of  the  medulla  oblongata. 
The  artery  formed  by  the  union  of  these  two  vessels  descends 
along  the  anterior  aspect  of  the  spinal  cord,  to  which  it  distributes 
branches. 

The  Posterior  spinal  winds  around  the  medulla  oblongata  to  the 
posterior  aspect  of  the  cord,  and  descends  on  either  side,  commu- 
nicating very  freely  with  the  spinal  branches  of  the  intercostal  and 
lumbar  arteries.  Near  its  commencement  it  sends  a  branch  upwards 
to  the  fourth  ventricle. 

The  Inferior  cerebellar  arteries  wind  around  the  upper  part  of  the 
medulla  oblongata  to  the  under  surface  of  the  cerebellum,  to  which 
they  are  distributed.  They  pass  between  the  filaments  of  origin  of 
the  hypoglossal  nerve  in  their  course,  and  anastomose  with  the 
superior  cerebellar  arteries. 

The  Transverse  branches  of  the  basilar  artery  supply  the  pons 
Varolii,  and  adjacent  parts  of  the  brain.  One  of  these  branches, 
larger  than  the  rest,  passes  along  the  crus  cerebelli  to  be  distributed 
to  the  anterior  border  of  the  cerebellum.  This  may  be  called  the 
middle  cerebellar  artery. 

The  Superior  cerebellar  arteries,  two  of  the  terminal  branches  of 
the  basilar,  wind  around  the  crus  cerebri  on  each  side  in  relation 
with  the  fourth  nerve,  and  are  distributed  to  the  upper  surface  of 
the  cerebellum  inosculating  with  the  inferior  cerebellar.  This 
artery  gives  off  a  small  branch  which  accompanies  the  seventh 
pair  of  nerves  into  the  meatus  auditorius  internus. 

The  Posterior  cerebral  arteries,  the  other  two  terminal  branches 
of  the  basilar,  wind  around  the  crus  cerebri  at  each  side,  and  are 
distributed  to  the  posterior  lobes  of  the  cerebrum.     They  are  sepa- 


310  THYKOID  AXIS — BRANCHES. 

rated  from  the  superior  cerebellar  artery,  near  the  origin,,  by  the 
third  pair  of  nerves,  and  are  in  close  relation  with  the  fourth  pair 
in  their  course  around  the  crura  cerebri.  Anteriorly,  near  their 
origin,  they  give  off  a  tuft  of  small  vessels,  which  enter  the  locus 
perforatus,  and  they  receive  the  posterior  communicating  arteries 
from  the  internal  carotid.  They  also  send  a  branch  to  the  velum 
interpositum  and  plexus  choroides. 

The  communications  established  between  the  anterior  cerebral 
arteries  in  front,  and  the  internal  carotids  and  posterior  cerebral 
arteries  behind,  by  the  communicating  arteries,  constitute  the  circle 
of  Willis.  This  remarkable  communication  at  the  base  of  the 
brain  is  formed  by  the  anterior  communicating  branch,  anterior 
cerebrals,  and  internal  carotid  arteries  in  front,  and  by  the  posterior 
communicating,  posterior  cerebrals,  and  basilar  artery  behind. 

The  Thyroid  Axis  is  a  short  trunk  which  divides  almost  imme- 
diately after  its  origin  into  four  branches,  some  of  which  are  occa- 
sionally branches  of  the  subclavian  artery  itself. 

The  Inferior  Thyroid  Artery  ascends  obliquely  in  a  serpentine 
course  behind  the  sheath  of  the  carotid  vessels,  to  the  inferior  part 
of  the  thyroid  gland,  to  which  it  is  distributed,  and  sends  branches 
to  the  trachea,  lower  part  of  the  larynx,  and  oesophagus.  It  is  in 
relation  with  the  middle  cervical  ganglion  of  the  sympathetic, 
which  lies  in  front  of  it. 

The  Supra-Scapular  Artery  (transversalis  humeri)  passes  ob- 
liquely outwards  behind  the  clavicle,  and  over  the  ligament  of  the 
supra-scapular  notch,  to  the  supra-spinatus  fossa.  It  crosses  in  its 
course  the  scalenus  anticus  muscle,  phrenic  nerve  and  subclavian 
artery,  is  distributed  to  the  muscles  on  the  dorsum  of  the  scapula, 
and  inosculates  with  the  posterior  scapular,  and  beneath  the  acro- 
mion process  with  the  dorsal  branch  of  the  subscapular  artery. 
At  the  supra-scapular  notch  it  sends  a  large  branch  to  the  trape- 
zius muscle.  The  supra-scapular  artery  is  not  unfrequently  a 
branch  of  the  subclavian. 

The  Posterior  Scapular  Artery  (transversalis  colli)  passes 
transversely  across  the  subclavian  triangle  at  the  root  of  the  neck, 
to  the  superior  angle  of  the  scapula.  It  then  descends  along  the 
posterior  border  of  that  bone  to  its  inferior  angle,  where  it  inoscu- 
lates with  the  subscapular  artery,  a  branch  of  the  axillary.  In  its 
course  across  the  neck  it  passes  in  front  of  the  scalenus  anticus, 
and  across  the  brachial  plexus  ;  in  the  rest  of  its  course  it  is  covered 
in  by  the  trapezius,  levator  anguli  scapula3,  rhomboideus  minor,  and 
rhomboideus  major  muscles.  Sometimes  it  passes  behind  the 
scalenus  anticus,  and  between  the  nerves  which  constitute  the 
brachial  plexus.  This  artery,  vi'hich  is  very  irregular  in  its  origin, 
proceeds  more  frequently  from  the  third  portion  of  the  subclavian 
artery  than  from  the  first. 

The  posterior  scapular  gives  branches  to  the  neck,  and  opposite 
the  angle  of  the  scapula  inosculates  with  the  profunda  cervicis.  It 
supplies  the  muscles  along  the  posterior  border  of  the  scapula,  and 


CIRCLE  OF  WILLIS. 


311 


establishes  an  important  anastomotic  communication  between  the 
branches  of  the  external  carotid,  subclavian,  and  axillary  arteries. 

Fig.  121. 


TheSuPERFiciALis  Cervicis  Artery  (cervicalis  anterior)  is  a  small 
vessel,  which  ascends  upon  the  anterior  tubercles  of  the  transverse 
processes  of  the  cervical  vertebrae,  lying  in  the  groove  between 
the  scalenus  anticus  and  rectus  anticus  major.  It  is  distributed  to 
the  deep  muscles  and  glands  of  the  neck,  and  sends  branches 
through  the  intervertebral  foramina  to  supply  the  spinal  cord  and 
its  membranes. 

The  Profunda  Cervicis  (cervicalis  posterior)  passes  backwards 
between  the  transverse  processes  of  the  seventh  cervical  and  first 
dorsal  vertebra,  and  then  ascends  the  back  part  of  the  neck, 
between  the  complexus  and  semi-spinalis  colli  muscles.     It  inoscu- 

Fig.  121.  The  circle  of  Willis.  The  branches  of  the  arteries  have  references  only 
on  one  side,  on  account  of  their  symmetrical  distribution.  1.  The  vertebral  arteries. 
2.  The  two  anterior  spinal  branches  uniting  to  form  a  single  vessel.  3.  One  of  the  pos- 
terior spinal  arteries.  4.  The  posterior  meningeal.  5.  The  inferior  cerebellar.  6.  The 
basilar  artery  giving  off  its  transverse  brandies  to  either  side.  7.  The  superior  cere- 
bellar artery.  8.  The  posterior  cerebral.  9.  The  posterior  communicating  branch  of 
the  internal  carotid.  10.  The  internal  carotid,  showing  the  curvatures  it  makes  within 
the  skull.  11.  The  ophthalmic  artery  divided  across.  12.  The  middle  cerebral  artery. 
13.  The  anterior  cerebral  arteries  connected  by,  14.  The  anterior  communicating 
artery. 


312  INTERNAL  MAMMARY  ARTERY. 

lates  above  with  the  princeps  cervicis  of  the  occipital  artery,  and 
below,  by  a  descending  branch,  with  the  posterior  scapular. 

The  Superior  Intep.costal  Artery  descends  behind  the  pleura 
upon  the  necks  of  the  first  two  ribs,  and  inosculates  with  the  first 
aortic  intercostal.  It  gives  off  two  branches  which  supply  the  two 
first  intercostal  spaces. 

The  Internal  Mammary  Artery  descends  by  the  side  of  the 
sternum,  resting  upon  the  costal  cartilages,  to  the  diaphragm  :  it 
then  pierces  the  anterior  fibres  of  the  diaphragm,  and  enters  the 
sheath  of  the  rectus,  where  it  inosculates  wiih  the  epigastric  artery, 
a  branch  of  the  external  iliac.  In  the  upper  part  of  its  course  it  is 
crossed  by  the  phrenic  nerve,  and  lower  down  lies  between  the 
triangularis  sterni  and  the  internal  intercostal  muscles. 

The  Branches  of  the  internal  mammary  are, — 

Anterior  intercostal, 

Mammary, 

Comes  nervi  phrenici, 

Mediastinal, 

Pericardiac, 

Musculo-phrenic. 

The  Anterior  iniercostals  supply  the  intercostal  muscles  of  the 
front  of  the  chest,  and  inosculate  with  the  aortic  intercostal  arteries. 
Each  of  the  three  first  anterior  intercostals  gives  off  a  large  branch 
to  the  mammary  gland,  which  anastomoses  freely  with  the  thoracic 
branches  of  the  axillary  artery ;  the  corresponding  branches  from 
the  remaining  intercostals  supply  the  integument  and  pectoralis 
major  muscle.  There  are  usually  two  anterior  intercostal  arteries 
in  each  space. 

The  Comes  nervi  phrenici  is  a  long  and  slender  branch  which 
accompanies  the  phrenic  nerve. 

The  mediastinal  and  pericardiac  branches  are  small  vessels  dis- 
tributed to  the  anterior  mediastinum,  the  thymus  gland,  and  peri- 
cardium. 

The  Musculo-phrenic  artery  winds  along  the  attachment  of  the 
diaphragm  to  the  ribs,  supplying  that  muscle  and  sending  branches 
to  the  inferior  intercostal  spaces.  "  The  mammary  arteries,"  says 
Dr.  Harrison,"  are  remarkable  for  the  number  of  their  inosculations, 
and  for  the  distant  parts  of  the  arterial  system  which  they  serve  to 
connect.  They  anastomose  with  each  other,  and  their  inosculations, 
with  the  thoracic  aorta,  encircle  the  thorax.  On  the  parietesof  this 
cavity  their  branches  connect  the  axillary  and  subclavian  arteries; 
on  the  diaphragm  they  form  a  link  in  the  chain  of  inosculations  be- 
tween the  subclavian  artery  and  abdominal  aorta,  and  in  the  parietes 
of  the  abdomen  they  form  an  anastomosis  most  remarkable  for  the 
distance  between  those  vessels  which  it  serves  to  connect;  namely, 
the  arteries  of  the  superior  and  inferior  extremities." 

Varieties  of  the  Subclavian  Arteries. — Varieties  in  these  arteries 
are  rare ;  that  which  most  frequently  occurs  is  the  origin  of  the  right 


AXILLARY  ARTERY.  313 

subclavian,  from  the  left  extremity  of  the  arch  of  the  aorta,  below 
the  left  subclavian  artery.  The  vessel,  in  this  case,  curves  behind 
the  oesophagus  and  right  carotid  artery,  and  sometimes  between  the 
oesophagus  and  trachea,  to  the  upper  border  of  the  first  rib,  on  the 
right  side  of  the  chest,  where  it  assumes  its  ordinary  course.  In  a 
case*  of  subclavian  aneurism  on  the  right  side,  above  the  clavicle, 
which  happened  during  the  present  summer,  Mr.  Liston  proceeded 
to  perform  the  operation  of  tying  the  carotid  and  subclavian  arteries 
at  their  point  of  division  from  tlie  innominata.  Upon  reaching  the 
point  where  the  bifurcation  should  have  existed,  he  found  that  there 
was  no  subclavian  artery.  With  that  admirable  self-possession 
which  distinguishes  this  eminent  surgeon  in  all  cases  of  em.ergency, 
he  continued  his  dissection  more  deeply,  towards  the  vertebral 
column,  and  succeeded  in  securing  the  artery.  It  was  ascertained 
after  death,  that  the  arteria  innominata  was  extremely  short,  and 
that  the  subclavian  was  given  oft' within  the  chest  from  the  posterior 
aspect  of  its  trunk,  and  pursued  a  deep  course  to  the  upper  mar- 
gin of  the  first  rib.  In  a  preparation  which  was  shown  to  me  in 
Heidelberg  some  years  since  by  Professor  Tiedemann,  the  right 
subclavian  artery  arose  from  the  thoracic  aorta,  as  low  down  as 
the  fourth  dorsal  vertebra,  and  ascended  from  that  point  to  the 
border  of  the  first  rib.  Varieties  in  the  branches  of  the  subclavian 
are  not  unfrequent ;  the  most  interesting  is  the  origin  of  the  left 
vertebral,  from  the  arch  of  the  aorta,  of  which  I  possess  several 
preparations. 

AXILLARY     ARTERY. 

The  axillary  artery  forms  a  gentle  curve  through  the  middle  of  the 
axillary  space  from  the  lower  border  of  the  first  rib  to  the  lower 
border  of  the  latissimus  dorsi,  where  it  becomes  the  brachial. 

Relations. — After  emerging  from  beneath  the  margin  of  the  costo- 
coracoid  membrane,  it  is  in  relation  with  the  axillary  vein,  which 
lies  at  first  to  the  inner  side  and  then  in  front  of  the  artery.  Near 
the  middle  of  the  axilla  it  is  embraced  by  the  two  heads  of  the 
median  nerve,  and  is  covered  in  by  the  pectoral  muscles.  Upon  the 
inner  or  thoracic  side  it  is  in  relation,  first,  with  the  fiist  intercostal 
muscle  ;  it  next  rests  upon  the  first  serration  of  the  serratus  magnus ; 
and  is  then  separated  from  the  chest  by  the  brachial  plexus  of  nerves. 
By  its  outer  or  humeral  side  it  is  at  first  separated  from  the  brachial 
plexus  by  a  triangular  cellular  interval ;  it  next  rests  against  the 
tendon  of  the  subscapularis  muscle;  and  thirdly  upon  the  coraco- 
brachialis  muscle. 

*  This  case  is  recorded  in  tlie  Lancet,  Vol.  I.  1839—40,  pp.  37  and  419. 

27 


314  AXILLARY  ARTERY. 

The  relations  of  the  axillary  artery  may  be  thus  arranged  : 
In  front.  Inner  or  thoracic  side.       Outer  or  humeral  side. 

Pec'toralis  major,  First  intercostal  muscle,  Plexus  of  nerves, 
Pectoralis  minor.  First  serration  of  ser-  Tendon  of  sub- 
Pectoralis  major.         ratus  magnus,  scapularis, 

.  Plexus  of  nerves.  Coraco-brachialis. 

Branches. — The  branches  of  the  Axillary  artery  are  seven  in 
number : 

Thoracica  acromialis, 
Superior  thoracic, 
Inferior  thoracic, 
Thoracica  axillaris, 
Subscapular, 
Circumflex  anterior, 
Circumflex  posterior. 

The  thoracica  acromialis  and  superior  thoracic  are  found  in  the 
triangular  space  above  the  pectoralis  minor. 

The  inferior  thoracic  and  thoracica  axillaris,  below  the  pectoralis 
minor. 

And  the  three  remaining  branches  belov\^  the  lower  border  of  the 
subscapularis. 

The  Thoracica  acromialis  is  a  short  trunk  which  ascends  to  the 
space  above  the  pectoralis  minor  muscle,  and  divides  into  three 
branches, — thoracic,  which  is  distributed  to  the  pectoral  muscles 
and  mammary  gland  ;  acromial,  which  passes  outwards  to  the 
acromion,  and  inosculates  with  the  branches  of  the  supra-scapular 
artery  ;  and  descending,  which  follows  the  interspace  between  the 
deltoid  and  pectoralis  major  muscles,  and  is  in  relation  with  the 
cephalic  vein. 

The  Superior  thoracic  (short),  very  frequently  arises  by  a  common 
trunk  with  the  preceding ;  it  runs  along  the  upper  border  of  the 
pectoralis  minor,  and  is  distributed  to  the  pectoral  muscles  and 
mammary  gland,  inosculating  with  the  intercostal  and  mammary 
arteries. 

The  Inferior  thoracic  (long  external  mammary)  descends  along 
the  lower  border  of  the  pectoralis  minor  to  the  side  of  the  chest.  It 
is  distributed  to  the  pectoralis  major  and  minor,  serratus  magnus, 
and  subscapularis  muscle,  to  the  axillary  glands  and  mammary 
gland ;  inosculating  with  the  superior  thoracic,  intercostal,  and 
mammary  arteries. 

The  Thoracica  axillaris  is  a  small  branch  distributed  to  the 
plexus  of  nerves  and  glands  in  the  axilla.  It  is  frequently  derived 
from  one  of  the  other  thoracic  branches. 

The  Subscapular  artery,  the  largest  of  the  branches  of  the  axil- 
lary, runs  along  the  lower  border  of  tlie  subscapularis  muscle,  to 
the  inferior  angle  of  the  scapula,  where  it  inosculates  with  the  pos- 
terior scapular,  a  branch  of  the  subclavian.  It  supplies,  in  its 
course,  the  muscles  on  the  under  surface,  and  inferior  border  of  the 


BRANCHES  OF  THE  AXILLARY  ARTERI. 


315 


Fig.  122. 


scapula,  and  the  side  of  the  chest.  At  about  an  inch  and  a  half 
from  the  axillary,  it  gives  off  a  large  branch,  the  dorsalis  scwpulcB, 
which  passes  backwards  through  the  triangular  space  bounded  by 
the  teres  minor,  teres  major  and  scapular  head  of  the  triceps,  and 
beneath  the  infra-spinatus  to  the  dorsum  of  the  scapula,  where  it 
is  distributed,  inosculating  with  the  supra-scapular  and  posterior 
scapular  arteries. 

The  Circumfiex  arteries  wind  around  the  neck  of  the  humerus. 
The  anterior,  very  small,  passes  be- 
neath the  coraco-brachialis  and  short 
head  of  the  biceps,  and  sends  a  branch 
upwards  along  the  bicipital  groove  to 
supply  the  shoulder-joint. 

The  Posterior  circuniflex,  of  larger 
size,  passes  backwards  through  the 
quadrangular  space  bounded  by  the 
teres  minor  and  major,  the  scapular 
head  of  the  triceps  and  the  humerus, 
and  is  distributed  to  the  deltoid  muscle 
and  joint.  Sometimes  this  artery  is  a 
branch  of  the  superior  profunda  of  the 
brachial.  It  then  ascends  behind  the 
tendon  of  the  teres  major,  and  is  dis- 
tributed to  the  deltoid  without  pass- 
ing through  the  quadrangular  space. 
The  posterior  circumflex  artery  sends 
branches  to  the  shoulder-joint. 

Varieties  of  the  Jlxillary  Artery. — 
The  most  frequent  peculiarity  of  this 
kind  is  the  division  of  the  vessel  into 
two  trunks  of  equal  size  ;  a  muscular 
trunk,  which  gives  ofii"  some  of  the 
ordinary  axillary  branches  and  sup- 
plies the  upper  arm,  and  a  continued 
trunk,  which  represents  the  brachial 
artery.  The  next  most  frequent  variety 
is  the  high  division  of  the  ulnar,  which  passes  down  the  arm  by  the 

Fig-.  122.  The  axillary  and  brachial  artery,  with  their  branches.  1.  The  deltoid 
muscle.  2.  The  biceps.  3.  The  tendinous  process  given  off  from  the  tendon  of  the 
biceps,  to  the  deep  fascia  of  the  fore-arm.  It  is  this  process  whicii  separates  the 
median  basilic  vein  from  the  brachial  artery.  4.  The  outer  border  of  tiie  brachialis 
anticus  muscle.  5.  The  supinator  longus.  6.  The  coraco-brachialis.  7.  The  middle 
portion  of  the  triceps  muscle.  8.  Its  inner  head.  9.  The  axillary  artery.  10.  The 
brachial  artery; — a  dark  line  marks  the  limit  between  these  two  vessels.  11.  The 
thoracica  acromialis  artery  dividing  into  its  three  branches  ;  the  number  rests  upon  the 
coracoid  process.  12.  The  superior  and  inferior  thoracic  arteries.  13.  The  serratus 
magnus  muscle.  14.  The  subscapular  artery.  The  posterior  circumflex  and  thoracica 
axillaris  branches  are  seen  in  tlie  figure  between  the  inferior  thoracic  and  subscapular 
The  anterior  circumflex  is  observed,  between  the  two  heads  of  the  biceps,  crossing  the 
neck  of  the  humerus.     15.  The  supeiior  profunda  artery.     16.  The  inferior  profunda. 

17.  The  anastomotica  mngna  inosculating  inferiorly,  with  the  anterior  ulnar  recurrent. 

18.  The  termination  of  the  superior  profunda,  inosculating  with  the  radial  recurrent  in 
the  interspace  between  the  brachialis  anticus  and  supinator  longus. 


316 


BRACHIAL  ARTERY BRANCHES, 


side  of  the  brachial  artery,  and  superficially  to  the  muscles  proceed- 
in^  from  the  inner  condyle,  to  its  ordinary  distribution  in  the  hand. 
In  this  course  it  lies  immediately  beneath  the  deep  fascia  of  the  fore- 
arm, and  may  be  seen  and  felt  pulsating  beneath  the  integument. 
The  hio-h  division  of  the  radial  from  the  axillary  is  rare.  In  one 
instance,  I  saw  the  axillary  artery  divide  into  three  branches  of 
nearly  equal  size,  which  passed  together  down  the  arm,  and  at  the 
bend  of  the  elbow  resolved  themselves  into  radial,  ulnar,  and  inter- 
osseous. But  the  most  interesting  variety,  both  in  a  physiological 
and  surgical  sense,  is  that  described  by  Dr.  Quain  in  his  "  Elements 
of  Anatomy."  "  I  found  in  the  dissecting-room,  a  few  years  ago,  a 
variety  not  hitherto  noticed  :  it  was  at  first  taken  for  the  ordinary 
high  division  of  the  ulnar  artery.  The  two  vessels  descended  from 
the  point  of  division  at  the  border  of  the  axilla,  and  lay  parallel  with 
one  another  in  their  course  through  the  arm  ;  but  instead  of  diverg- 
ing, as  is  usual  at  the  bend  of  the  elbow,  they  converged,  and  united 
so  as  to  form  a  short  trunk,  which  soon  divided  again  into  the  radial 
and  ulnar  arteries  in  the  regular  way."  In  a  subject,  dissected 
durin^  the  past  winter  in  Sydenham  College,  this  variety  existed  in 
both  arms ;  and  I  have  seen  several  other  instances  of  a  similar 
kind. 

BRACHIAL     ARTERY. 

The  Brachial  artery  passes  down  the  inner  side  of  the  arm,  from 
the  lower  border  of  the  latissimus  dorsi  to  the  bend  of  the  elbow, 
where  it  divides  into  the  radial  and  ulnar  arteries. 

Relations. — In  its  course  downwards,  it  rests  upon  the  coraco- 
brachialis  muscle,  internal  head  of  the  triceps,  brachialis  anticus, 
and  the  tendon  of  the  biceps.  To  its  inner  side  is  the  ulnar  nerve  ; 
to  the  outer  side,  the  coraco-brachialis  and  biceps  muscles;  in  front 
it  has  the  basilic  vein,  and  is  crossed  by  the  median  nerve.  Its  re- 
lations, within  its  sheath,  are  the  venas  comites. 

Plan  of  the  relations  of  the  Brachial  Artery. 

In  Front. 
Basilic  vein, 
Deep  fascia, 
Median  nerve, 


Inner  Side. 
Ulnar  nerve. 


Brachial  Artery. 


Outer  Side. 
Coraco-bi-achialis, 
Biceps. 


Behind. 
Short  head  of  triceps, 
Coraco-brachiiilis, 
Brachialis  anticus, 
Tendon  of  biceps. 

The  branches  of  the  brachial  artery  are,  the — 
Superior  profunda, 
Inferior  profunda, 
Anastomotica  magna, 
Muscular. 


RADIAL  ARTERY.  317 

The  Superior  profunda  arises  opposite  the  lower  border  of  the 
latissimus  dorsi,  and  winds  around  the  humerus,  between  the  triceps 
and  the  bone,  in  the  space  between  the  brachialis  anticus  and  supi- 
nator longus,  where  it  inosculates  with  the  radial  recurrent  branch. 
It  accompanies  the  musculo-spiral  nerve.  In  its  course  it  gives  off 
the  posterior  articular  artery,  which  descends  to  the  elbow-joint,  and 
a  more  superficial  branch,  which  inosculates  with  the  interosseous 
articular  artery. 

The  Inferior  profunda  arises  from  about  the  middle  of  the  brachial 
arte  ry,  and  descends  to  the  space  between  the  inner  condyle  and 
olecranon  in  company  with  the  ulnar  nerve,  where  it  inosculates 
with  the  posterior  ulnar  recurrent. 

The  Anastomot'ca  magna  is  given  off  nearly  at  right  angles  from 
the  brachial,  at  about  two  inches  above  the  joint.  It  passes  directly 
inwards,  and  divides  into  two  branches,  which  inosculate  with  the 
anterior  and  posterior  ulnar  recurrent  arteries  and  with  the  inferior 
profunda. 

The  Muscular  branches  are  distributed  to  the  muscles  in  the 
course  of  the  artery,  viz.  to  the  coraco-brachialis,  biceps,  deltoid, 
brachialis  anticus  and  triceps. 

Varieties  of  the  Brachial  Artery. — The  most  frequent  peculiarity 
in  the  distribution  of  branches  from  this  artery  is  the  high  division 
of  the  radial,  which  arises  generally  from  about  the  upper  third  of 
the  brachial  artery  and  descends  to  its  normal  position  at  the  bend 
of  the  elbow.  The  ulnar  artery  sometimes  arises  from  the  brachial 
at  about  two  inches  above  the  elbow,  and  pursues  either  a  superfi- 
cial or  deep  course  to  the  wrist;  and  in  more  than  one  instance  I 
have  seen  the  interosseous  artery  arise  from  the  brachial  a  little 
above  the  bend  of  the  elbow.  The  two  profunda  arteries  occa- 
sionally arise  by  a  common  trunk,  or  there  may  be  two  superior 
profundee. 

RADIAL     ARTERY. 

The  Radial  artery,  one  of  the  divisions  of  the  brachial,  appears 
from  its  direction  to  be  the  continuation  of  that  trunk.  It  runs  along 
the  radial  side  of  the  fore-arm,  from  the  bend  of  the  elbow  to  the 
wrist ;  it  there  turns  round  the  base  of  the  thumb,  beneath  its  ex- 
tensor tendons,  and  passes  between  the  two  heads  of  the  first  dorsal 
interosseous  muscle,  into  the  palm  of  the  hand.  It  then  crosses  the 
metacarpal  bones  to  the  ulnar  side  of  the  hand,  forming  the  deep 
palmar  arch,  and  terminates  by  inosculating  with  the  superficial 
palmar  arch. 

In  the  upper  half  of  its  course,  the  radial  artery  is  situated  between 
the  supinator  longus  muscle,  by  which  it  is  overlapped  superiorly, 
and  the  pronator  radii  teres ;  in  the  lower  half,  between  the  tendons 
of  the  supinator  longus  and  flexor  carpi  radialis.  It  rests  in  its 
course  downwards,  upon  the  supinator  brevis,  pronator  radii  teres, 
radial  origin  of  the  flexor  sublimis,  flexor  longus  pollicis,  and  pro- 

27* 


318 


BADIAL  ARTERY. 


nator  quadratus;  and  it  is  covered  in  by  the  integument  and  fascias. 
At  the  wrist  it  is  situated  in  contact  with  the  dorsal  carpal  liga- 
ments and  beneath  the  extensor  tendons  of  the  thumb;  and  in  the 
palm  of  the  hand,  beneath  the  flexor  tendons.  It  is  accompanied 
by  venae  comites  throughout  its  course,  and  for  its  middle  third  is 
in  close  relation  with  the  radial  nerve. 

Plan  of  the  relations  of  the  Radial  Artery  in  the  fore-arm. 

In  Front. 
Deep  fascia, 
Supinator  longus. 


Inner  Side. 

Pronator  radii  teres, 
Flexor  carpi  radialis. 


Outer  Side, 
Supinator  longus, 
Radial  nerve  (middle  third 
of  its  course). 


Behind. 

Supinator  brevis, 
Pronator  radii  teres, 
Flexor  sublimis  digitorum, 
Flexor  longus  poUicis, 
Pronator  quadratus. 
Wrist-joint. 

The  Branches  of  the  radial  artery  may  be  arranged  into  three 
groups,  corresponding  with  the  three  regions,  the  fore-arm,  the  wrist, 
and  the  hand ;  they  are — 


Fore-arm, 


Recurrent  radial, 
Muscular. 


Wrist, 


Hand, 


Superficialis  volas, 

Carpalis  anterior, 

Carpalis  posterior,  or  dorsalis  carpi, 

Metacarpalis, 

Dorsales  pollicis. 

Princeps,  or  magna  pollicis, 
Radialis  indicis, 
InterossesB, 
Perforantes. 

The  Recurrent  branch  is  given  off  immediately  below  the  elbow  ; 
it  ascends  in  the  space  between  the  supinator  longus  and  brachialis 
anticus  to  supply  the  joint,  and  inosculates  with  the  terminal  branches 
of  the  superior  profunda.  This  vessel  gives  off  numerous  muscular 
branches. 

The  Muscular  branches  are  distributed  to  the  muscles  on  the  radial 
side  of  the  fore-arm. 

The  Swperficialis  voice  is  given  off  from  the  radial  artery  while  at 
the  wrist.  It  passes  between  the  fibres  of  the  abductor  pollicis 
muscle,  and  inosculates  with  the  termination  of  the  ulnar  artery, 
completing  the  superficial  palmar  arch.  This  artery  is  very  variable 


RADIAL  ARtERr BRANCHES. 


319 


Fig.  123. 


in  size,  being  sometimes  as  large  as  the  continuation  of  the  radial, 
and  at  other  times  a  mere  muscular  ramusculus,  or  entirely  wanting ; 
when  of  large  size  it  supplies  the  palmar 
side  of  the  thumb  and  the  radial  side  of  the 
index  finger. 

The  Carpal  branches  are  intended  for  the 
supply  of  the  wrist,  the  anterior  carpal  in 
front,  and  the  posterior,  the  larger  of  the 
two,  beltind.  The  car'palis  ■posterior  crosses 
the  carpus  transversely  to  the  ulnar  border 
of  the  hand,  where  it  inosculates  with  the 
posterior  carpal  branch  of  the  ulnar  artery. 
Superiorly  it  sends  branches  which  inoscu- 
late with  the  termination  of  the  anterior 
interosseous  artery ;  inferiorly,  it  gives  off 
•posterior  ivterosseotis  branches,  which  anas- 
tomose with  the  perforating  branches  of  the 
deep  palmar  arch,  and  then  run  forwards 
upon  the  dorsal  interossei  muscles. 

The  Metacarpal  branch  runs  forwards 
on  the  second  dorsal  interosseous  muscle, 
and  inosculates  with  the  digital  branch  of 
the  superficial  palmar  arch,  which  supplies 
the  adjoining  sides  of  the  index  and  middle 
fingers.  Sometimes  it  is  of  large  size,  and 
the  true  continuation  of  the  radial  artery. 

The  Dorsales  poUicis  are  two  small 
branches  which  run  along  the  sides  of  the 
dorsal  aspect  of  the  thumb. 

The  Princeps  poinds  descends  along  the 
border  of  the  metacarpal  bone,  between  the 
abductor  indicis  and  adductor  pollicis  to  the 
base  of  the  first  phalanx,  where  it  divides 

into  two  branches,  which  are  distributed  to  the  two  sides  of  the 
palmar  aspect  of  the  thumb. 

The  Radialis  indicis  is  also  situated  between  the  abductor  indicis 


Fig.  123.  The  arteries  of  the  forearm.  1.  The  lower  part  of  the  biceps  muscle.  2. 
The  inner  condyle  of  the  humerus  with  the  humeral  oriorin  of  the  pronator  radii  teres 
and  flexor  carpi  radialis  divided  across.  3.  The  deep  portion  of  the  pronator  radii 
teres.  4.  The  supinator  longus  muscle.  5.  The  flexor  longfus  pollicis.  6.  The  pronator 
quadratus.  7.  The  flexor  profundus  digitorum.  8.  The  flexor  carpi  ulniiris.  9.  The 
anpular  ligfnment  with  the  tendons  passing  beneath  it  into  the  palm  of  the  hand;  the 
figure  is  placed  on  the  tendon  of  the  palmaris  longus  muscle,  divided  close  to  its  inser- 
tion. 10.  The  brachial  artery.  11.  The  anastomotica  magna  inosculatinjr  superiorly 
with  the  inferior  profunda,  and  inferiorly  with  the  anterior  ulnar  recurrent.  i2.  The 
radial  artery.  13.  The  rndial  recurrent  artery  inosculating  with  the  termination  of 
the  superior  profunda.  14.  The  superficiilis  volas.  15.  The  ulnar  artery.  Ifi.  Its 
superficial  palmar  arch  giving  off"  digital  branches  to  three  fingers  and  a  half.  17. 
The  magna  pollicis  and  radialis  indicis  arteries.  18.  The  posterior  ulnar  recurrent. 
IP.  The  anterior  interosseous  artery.  20.  The  posterior  interosseous,  as  it  is  passing 
througii  the  interosseous  membrane. 


320  ULNAR  ARTERY. 

and  adductor  pollicis,  and  runs  along  the  radial  side  of  the  index 
jfinger,  forming  its  collateral  artery.  This  vessel  is  frequently  a 
branch  of  the  princeps  pollicis. 

The  Inlerossece,  three  or  four  in  number,  are  branches  of  the  deep 
palmar  arch ;  they  pass  forwards  upon  the  interossei  muscles  and 
inosculate  with  the  digital  branches  of  the  superficial  arch,  opposite 
the  heads  of  the  metacarpal  bones. 

The  Perforantes,  three  in  number,  pass  directly  backwards  be- 
tween the  heads  of  the  dorsal  interossei  muscles,  and  inosculate  with 
the  posterior  interosseous  arteries. 

ULNAR     ARTERY. 

The  Ulnar  artery,  the  other  division  of  the  brachial  artery,  crosses 
the  arm  obliquely  to  the  commencement  of  its  middle  third  ;  it  then 
runs  down  the  ulnar  side  of  the  fore-arm  to  the  wrist,  crosses  the 
annular  ligament,  and  forms  the  superficial  palmar  arch,  which  ter- 
minates by  inosculating  with  the  superficialis  volae. 

Relations. — In  the  upper  or  oblique  portion  of  its  course,  it  lies 
upon  the  brachialis  anticus,  and  flexor  profundus  digitorum  ;  and  is 
covered  in  by  the  superficial  layer  of  muscles  of  the  fore-arm  and 
the  median  nerve.  In  the  second  part  of  its  course,  it  is  placed  upon 
the  flexor  profundus,  and  pronator  quadratus,  lying  between  the 
flexor  carpi  ulnaris  and  flexor  sublimis  digitorum.  While  crossing 
the  annular  ligament  it  is  protected  from  injury  by  a  strong  tendi- 
nous arch  thrown  over  it  from  the  pisiform  bone  :  and  in  the  palm 
it  rests  upon  the  tendons  of  the  flexor  sublimis,  being  covered  in  by 
the  palmaris  brevis  muscle  and  palmar  fascia.  It  is  accompanied 
in  its  course  by  the  vense  comites,  and  is  in  relation  with  the  ulnar 
nerve  for  the  lower  two-thirds  of  its  extent. 

Plan  of  the  relations  of  the  Ulnar  Artery. 

In  Front. 
Deep  fascia, 

Superficial  layer  of  muscles, 
Median  nerve. 

In  the  Hand. 
Tendinous  arch,  from  the  pisiform  bone, 


Palmaris  brevis  muscle, 
Palmar  fascia. 

Inner  Side. 
Flexor  carpi  ulnaris, 
Ulnar  nerve  (lower  two- 
thirds.) 


Ulnar  Artery. 


Outer  Side. 
Flexor  sublimis  digito- 


Behind. 
Brachialis  anticus, 
Flexor  profundus  digitorum, 
Pronator  quadratus. 

In  the  Hand. 

Annular  liffarnent, 

Tcndonb  of  the  flexor  sublimis  di-ritorum. 


ULNAR  ARTERY BRANCHES.  321 

The  Branches  of  the  ulnar  artery  may  be  arranged  like  those  of 
the  radial  into  three  groups : 

Anterior  ulnar  recurrent. 

Posterior  ulnar  recurrent, 

Fore-arm    i  Interosseous         S  Anterior  interosseous, 


Posterior  interosseous, 

Muscular. 

rx7  .  (  Carpalis  anterior, 

'^^    '        \  Carpalis  posterior,  or  dorsalls  manus. 

Hand  .  Digitales. 

The  Antprior  ulnar  recM?Tff77i  arises  immediately  below  the  elbow, 
and  ascends  in  front  of  the  joint  between  the  pronator  radii  teres 
and  brachialis  anticus,  where  it  inosculates  with  anastomotica 
magna  and  inferior  profunda.  The  two  recurrent  arteries  frequently 
arise  by  a  common  trunk. 

The  Posterior  ulnar  recurrent,  larger  than  the  preceding,  arises 
immediately  below  the  elbow-joint,  and  passes  backwards  beneath 
the  origins  of  the  superficial  layer  of  muscles  ;  it  then  ascends  be- 
tween the  two  heads  of  the  flexor  carpi  ulnaris,  and  beneath  the 
ulnar  nerve,  and  inosculates  with  the  inferior  profunda  and  anasto- 
motica magna. 

The  Common  interosseous  artery  is  a  short  trunk  which  arises 
from  the  ulnar,  opposite  to  the  bicipital  tuberosity  of  the  radius.  It 
divides  into  two  branches,  the  anterior  and  posterior  interosseous 
arteries. 

The  Anterior  interosseous  passes  down  the  fore-arm  upon  the  in- 
terosseous membrane,  between  the  flexor  profundus  digitorum  and 
flexor  longus  pollicis,  and  behind  the  pronator  quadratus  it  pierces 
that  membrane  and  descends  to  the  back  of  the  wrist,  where  it  inos- 
culates with  the  posterior  carpal  branches  of  the  radial  and  ulnar. 
It  is  retained  in  connexion  with  the  interosseous  membrane  by  means 
of  a  thin  aponeurotic  arch. 

The  anterior  interosseous  artery  sends  a  branch  to  the  median 
nerve,  which  it  accompanies  into  the  hand.  The  median  artery  is 
sometimes  of  large  size,  and  I  have  seen  it  take  the  place  of  the 
superficial  palmar  arch. 

The  Posterior  interosseous  artery  passes  backwards  through  an 
opening  between  the  upper  part  of  the  interosseous  membrane  and 
the  oblique  ligament,  and  is  distributed  to  the  muscles  on  the  poste- 
rior aspect  of  the  fore-arm.  It  gives  oflT  a  recurrent  branch,  which 
returns  upon  the  ejbow  between  the  anconeus,  extensor  carpi  ulnaris 
and  supinator  brevis  muscles,  and  anastomoses  with  the  posterior 
terminal  branches  of  the  superior  profunda. 

The  Muscular  branches  supply  the  muscles  situated  along  the 
ulnar  border  of  the  fore-arm. 

The  Car-pal  branches,  anterior  and  posterior,  are  distributed  to  the 


322  BRANCHES  OF  THE  THORACIC  AORTA. 

anterior  and  posterior  aspects  of  the  wrist-joint,  where  they  inoscu- 
late with  corresponding  branches  of  the  radial  artery. 

The  Digital  branches  are  given  off  from  the  superficial  palmar 
arch,  and  are  four  in  number.  The  first  and  smallest  is  distributed 
to  the  ulnar  side  of  the  little  finger.  The  other  three  are  short 
trunks,  which  divide  between  the  heads  of  the  metacarpal  bones, 
and  form  the  collateral  branch  of  the  radial  side  of  the  little  finger, 
the  collateral  branches  of  the  ring  and  middle  fingers,  and  the  col- 
lateral branch  of  the  ulnar  side  of  the  index  finger. 

The  Superficial  palmar  arch  receives  the  termination  of  the  deep 
palmar  arch  from  between  the  abductor  minimi  digiti  and  flexor 
brevis  minimi  digiti  near  to  their  origins,  and  terminates  by  inoscu- 
lating with  the  superficialis  volas  upon  the  ball  of  the  thumb.  The 
communication  between  the  superficial  and  deep  arch  is  generally 
described  as  the  communicating  branch  of  the  ulnar  artery. 

The  mode  of  distribution  of  the  arteries  to  the  hand  is  subject  to 
great  variety. 

BRANCHES  OF  THE  THORACIC  AORTA. 

Bronchial, 

Esophageal, 
Intercostal. 

The  Bronchial  Arteries  are  four  in  number,  and  vary  both  in 
size  and  origin.  They  are  distributed  to  the  bronchial  glands  and 
lubes,  and  send  branches  to  the  oesophagus,  pericardium,  and  left 
auricle  of  the  heart.     These  are  the  nutritious  vessels  of  the  lungs. 

The  (Esophageal  Arteries  are  numerous  small  branches  ;  they 
arise  from  the  anterior  part  of  the  aorta,  are  distributed  to  the  oeso- 
phagus, and  establish  a  chain  of  anastomosis  along  that  tube :  the 
superior  inosculate  with  the  bronchial  arteries,  and  with  oeso- 
phageal branches  of  the  inferior  thyroid  arteries ;  and  the  inferior 
with  similar  branches  of  the  phrenic  and  gastric  arteries. 

The  Intercostal,  or  posterior  intercostal  arteries,  arise  from  the 
posterior  part  of  the  aorta  ;  they  are  nine  in  number  on  each  side, 
the  two  superior  spaces  being  supplied  by  the  superior  intercostal 
artery,  a  branch  of  the  subclavian.  The  right  intercostals  are 
longer  than  the  left,  on  account  of  the  position  of  the  aorta.  They 
ascend  somewhat  obliquely  from  their  origin,  and  cross  the  verte- 
bral column  behind  the  thoracic  duct,  vena  azygos  major,  and 
sympathetic  nerve,  to  the  intercostal  spaces,  the  left  passing  beneath 
the  superior  intercostal  vein,  the  vena  azygos  minor  and  sympathetic. 
In  the  intercostal  spaces,  or  rather,  upon  the  external  intercostal 
muscles,  each  artery  gives  off  a  dorsal  branch,  which  passes  back 
between  the  transverse  processes  of  the  vertebra;,  lying  internally 
to  the  middle  costo-transverse  ligament,  and  divides  into  a  spinal 
branch,  which  supplies  the  spinal  cord  and  vertebroc,  and  a  mus- 
cular branch  which  is  distributed  to  the  muscles  and  integument 
of  the  back.     It  then  comes  into  relation  with  its  vein  and  nerve, 


BRANCHES  OF  THE  ABDOMINAL  AORTA.  323 

the  former  being  above,  and  the  latter  below,  and  divides  into  two 
branches  which  run  along  the  borders  of  the  contiguous  ribs  be- 
tween the  two  planes  of  intercostal  muscles,  and  anastomose  with 
the  anterior  intercostal  arteries,  branches  of  the  internal  mammary. 
The  branch  corresponding  with  the  lower  border  of  each  rib  is  the 
larger  of  the  two.  They  are  protected  from  pressure  during  the 
action  of  the  intercostal  muscles,  by  little  tendinous  arches  thrown 
across  and  attached  by  each  extremity  to  the  bone. 

BRANCHES     OF     THE     ABDOMINAL     AORTA. 

Phrenic, 

(  Gastric, 
Coeliac  axis  ■<  Hepatic, 

(  Splenic, 
Superior  mesenteric, 
Spermatic, 
Inferior  mesenteric, 
Supra-renal,  or  capsular, 
Renal,  or  emulgent, 
Lumbar, 
Sacra  media. 

The  Phremg  Arteries  are  given  off  from  the  anterior  part  of 
the  aorta  as  soon  as  that  trunk  has  passed  through  the  aortic 
opening.  Passing  obliquely  outwards  upon  the  under  surface  of 
the  diaphragm,  each  artery  divides  into  two  branches,  an  internal 
branch  which  runs  forwards  and  inosculates  with  its  fellow  of  the 
opposite  side  in  front  of  the  oesophageal  opening ;  and  an  external 
branch  which  proceeds  outwards  towards  the  great  circum- 
ference of  the  muscle,  and  sends  branches  to  the  supra-renal 
capsules.  The  phrenic  arteries  inosculate  with  branches  of  the  in- 
ternal mammary,  inferior  intercostal,  epigastric,  oesophageal,  gastric, 
hepatic,  and  supra-renal  arteries.  They  are  frequently  derived  from 
the  coeliac  axis,  or  from  one  of  its  divisions,  and  sometimes  they 
give  off  the  supra-renal  arteries. 

The  CcELiAc  Axis  (xojXi'a,  ventriculus)  is  the  first  single  trunk 
given  off  from  the  abdominal  aorta.  It  arises  opposite  the  upper 
border  of  the  first  lumbar  vertebrae,  is  about  half  an  inch  in  length, 
and  divides  into  three  large  branches — gastric,  hepatic,  and  splenic. 

Relations. — The  trunk  of  the  coeliac  axis  has  in  relation  with  it, 
in  front  the  lesser  omentum;  on  the  right  side  the  right  semilunar 
ganglion  and  lobulus  Spigelii  of  the  liver;  on  the  left  side  the  left 
semilunar  ganglion  and  cardiac  portion  of  the  stomach  ;  and  beloia 
the  upper  border  of  the  pancreas  and  lesser  curve  of  the  stomach. 
It  is  completely  surrounded  by  the  solar  plexus. 

The  Gastric  Artery  (coronaria  ventriculi),  the  smallest  of  the 
three  branches  of  the  cceliac  axis,  ascends  between  the  two  layers 
of  the  lesser  omentum  to  the  cardiac  orifice  of  the  stomach,  then 
runs  along  the  lesser  curvature  to  the  pylorus,  and  inosculates  with 


3  24 


ABDOMINAL  AORTA. 


the  pyloric  branch  of  the  hepatic.  It  is  distributed  to  the  lower 
extremity  of  the  oesophagus  and  lesser  curve  of  the  stomach,  and 
anastomoses  with  the  oesophageal  arteries  and  vasa  brevia  of  the 
splenic  artery. 

Fiff.  124. 


The  Hepatic  Artery  curves  forwards,  and  ascends  along  the  right 
border  of  the  lesser  omentum  to  the  liver,  where  it  divides  into  two 
branches  (right  and  left),  which  enter  the  transverse  fissure,  and  are 
distributed  along  the  portal  canals  to  the  right  and  left  lobes.*  It  is 
in  relation  in  the  right  border  of  the  lesser  omentum,  with  the  ductus 
communis  choledochus  and  portal  vein,  and  is  surrounded  by  the 

Fig.  124.  The  abdominal  aorta  with  its  branches.  1.  The  phrenic  arteries.  2.  The 
coeliac  axis.  3.  Tlie  gastric  artery.  4.  The  hepatic  artery,  dividing  into  the  right 
and  left  iiepatic  branches.  5.  The  splenic  artery,  passing  outwards  to  the  spleen. 
6.  'J'he  supr.j-rcnal  artery  of  the  right  side.  7.  Tiie  right  renal  artery,  which  is  longer 
than  the  left,  passing  outwards  to  the  right  kidney.  8.  The  lumbar  arteries.  9.  Tjie 
superior  mesenteric  artery.  10.  The  two  spermatic  arteries.  11.  The  inferior  mcsen. 
tcric  artery.  12.  The  sacra  media.  13.  The  common  iliacs.  14.  The  internal  iliac 
of  the  right  side.  1.5.  The  cxleiniil  iliac  artery.  IG.  The  epigastric  artery.  17.  The 
circurnflexa  ilii  artery.      18.  The  femoral  arleiy. 

»  For  the  mode  of  distribution  of  the  hepatic  artery  within  the  liver,  see  the  "Minute 
Anatomy"  of  that  organ  in  the  Chapter  on  the  Viscera. 


SPLENIC  ARTERY — BRANCHES.  325 

hepatic  plexus  of  nerves  and  numerous  lymphatics.  There  are  some- 
times two  hepatic  arteries,  in  which  case  one  is  derived  from  the 
superior  mesenteric  artery. 

The  Branches  of  the  hepatic  artery  are  the 

Pyloric, 

^     ,      J     J       T         (   Gastro-epiploica  dextra, 
Gastro-duodenahs,       \    ^  5      j     j       r 

(   rancreatico-duodenaiis. 

Cystic. 

The  Pyloric  branch,  given  off  from  the  hepatic  near  to  the  pylorus, 
is  distributed  to  the  commencement  of  the  duodenum  and  to  the 
lesser  curve  of  the  stomach,  where  it  inosculates  with  the  gastric 
artery. 

The  Gastro-duodenalis  artery  is  a  short  but  large  trunk,  which 
descends  behind  the  pylorus,  and  divides  into  two  branches,  the 
gastro-epiploica  dextra,  and  pancreatico-duodenalis.  Previously  to 
its  division,  it  gives  off  some  inferior  -pyloric  branches  to  the  small 
end  of  the  stomach. 

The  Gastro-epiploica  dextra  runs  along  the  great  curve  of  the 
stomach  lying  between  the  two  layers  of  the  great  omentum,  and 
inosculates  at  about  its  middle  with  the  gastro-epiploica  sinistra,  a 
branch  of  the  splenic  artery.  It  supplies  the  great  curve  of  the 
stomach  and  the  great  omentum ;  hence  the  derivation  of  its  name. 

The  Pancreatico-duodenalis  curves  along  the  fixed  border  of  the 
duodenum,  partly  concealed  by  the  attachment  of  the  pancreas,  and 
is  distributed  to  the  pancreas  and  duodenum.  It  inosculates  infe- 
riorly  with  the  first  jejunal  and  with  the  pancreatic  branches  of  the 
superior  mesenteric  artery. 

The  Cystic  artery,  generally  a  branch  of  the  right  hepatic,  is  of 
small  size,  and  ramifies  between  the  coats  of  the  gall  bladder,  pre- 
viously to  its  distribution  to  the  mucous  membrane. 

The  Splenic  Artery,  the  largest  of  the  three  branches  of  the 
coeliac  axis,  passes  horizontally  to  the  left  along  the  upper  border  of 
the  pancreas,  and  divides  into  five  or  six  large  branches  which  enter 
the  hilum  of  the  spleen  and  are  distributed  to  its  structure.  In  its 
course  it  is  tortuous  and  serpentine,  and  frequently  makes  a  com- 
plete turn  upon  itself.  It  lies  in  a  narrow  groove  in  the  upper  border 
of  the  pancreas,  and  is  accompanied  by  the  splenic  vein,  and  by  the 
splenic  plexus  of  nerves. 

The  Branches  of  the  splenic  artery  are — 

PancreaticsB  parvas, 
Pancreatica  magna, 
Vasa  bievia, 
Gastro-epiploica  sinistra. 

The  PancreoticcB  parvce  are  numerous  small  branches  distributed 
to  the  pancreas,  as  the  splenic  artery  runs  along  its  upper  border. 

28 


326  SUPERIOR  MESENTERIC  ARTERY. 

One  of  these,  larger  than  ihe  rest,  follows  the  course  of  the  pancre- 
atic duct,  and  is  called  pancreatica  magna. 

The  Vasa  brevia  are  five  or  six  branches  of  small  size  which 
pass  fron^  the  extremity  of  the  splenic  artery  and  its  terminal 
branches,  between  the  layers  of  the  gastro-splenic  omentum,  to  the 
great  end  of  the  stomach,  to  which  they  are  distributed,  inoscu- 
lating with  branches  of  the  gastric  artery  and  of  the  gastro-epiploica 
sinistra. 

The  Gastro-epiploica  sinistra  appears  to  be  the  continuation  of 
the  splenic  artery ;  it  passes  forwards  from  left  to  right,  along  the 
great  curve  of  the  stomach,  lying  between  the  layers  of  the  great 
omentum,  and  inosculates  with  the  gastro-epiploica  dextra.  It  is 
distributed  to  the  greater  curve  of  the  stomach  and  to  the  great 
omentum. 

Fig.  125. 


The  Superior  Mesenteric  Artery,  the  second  of  the  single 
trunks,  and  next  in  size  to  the  cceliac  axis,  arises  from  the  aorta 

Fig.  125.  The  distribution  of  the  branches  of  the  cceliac  axis.  1.  The  liver.  2.  Its 
transverse  fissure.  3.  The  g-all  bladder.  4.  The  stomach.  5.  The  entrance  of  the 
tEsophagus.  6.  The  pylorus.  7.  The  duodenum,  its  descending  portion.  8.  The 
transverse  portion  of  the  duodenum.  9.  The  pancreas.  10.  The  spleen.  11.  The 
aorta.  12.  The  ccDliac  axis.  13.  The  gastric  artery.  14.  The  hepatic  artery.  15. 
Its  pyloric  branch.  16.  The  gastro-duodenalis.  17.  The  gastro-epiploica  dextra.  18. 
The  pancreatico-duodenalis,  inosculating  with  a  branch  from  the  superior  mesenteric 
artery.  19.  The  division  of  the  hepatic  artery  into  its  right  and  left  branches;  the 
right  giving  off  the  cystic  branch.  20.  The  splenic  artery,  traced  by  dotted  lines  be- 
hind the  stomach  to  the  spleen.  21.  The  ga.stro-epiploica  sinistra,  inosculiiling  along 
the  great  curvature  of  the  stomach  with  the  gastro-epiploica  dextra.  22.  The  pan- 
creatica magna.  23.  Tiie  vasa  brevia  to  the  great  end  of  the  stomach,  inosculating 
with  branches  of  the  gastric  artery.  24.  The  superior  mesenteric  artery,  emerging 
from  between  the  pancreas  and  the  transverse  portion  of  the  duodenum. 


SUPEHIOR  MESENTERIC  ARTERY. 


327 


immediately  below  that  vessel  and  behind  the  pancreas.  It  passes 
forwards  between  the  pancreas  and  transverse  duodenum,  and  de- 
scends within  the  layers  of  the  mesentery,  to  the  right  iliac  fossa, 
where  it  terminates,  very  much  diminished  in  size.  It  forms  a 
curve  in  its  course,  the  convexity  being  directed  towards  the  left, 
and  the  concavity  to  the  right.  It  is  in  relation  near  its  commence- 
ment with  the  portal  vein  ;  and  is  accompanied  by  two  veins,  and 
the  superior  mesenteric  plexus  of  nerves. 

The  branches  of  the  superior  Mesenteric  Artery  are — 

Vasa  intestini  tenuis, 
Ileo-colica, 
Colica  dextra, 
Colica  media. 


Fiff.  126. 


Fig.  126.  The  course  and  distribution  of  the  superior  mesenteric  artery.  1.  The 
descending  portion  of  the  duodenum.  2.  The  transverse  portion.  3.  The  pancreas. 
4.  The  jejunum.  5.  The  ileum.  6.  The  ccecum,  from  which  the  appendix  vermiformis 
is  seen  projecting.  7.  The  ascending  colon.  8.  The  transverse  colon.  9.  The  com- 
mencement of  the  descending  colon.  10.  The  superior  mesenteric  artery.  11.  The 
colica  media.  12.  The  branch  which  inosculates  with  the  colica  sinistra,  13.  The 
branch  of  the  superior  mesenteric  artery,  which  inosculates  with  the  pancreatico-duo- 
denalis.  14.  The  colica  dextra.  15.  The  ileo-colica.  16,  16.  The  branches  from  the 
convexity  of  the  superior  mesenteric  to  the  small  intestines. 


328  SPEKMATIC  ARTERIES. 

The  Vasa  intestini  tenuis  arise  from  the  convexity  of  the  superior 
mesenteric  artery.  They  vary  from  fifteen  to  twenty  in  number, 
and  are  distributed  to  the  small  intestine  from  the  duodenum  to  the 
termination  of  the  ileum.  In  their  course  between  the  layers  of  the 
mesentery,  they  form  a  series  of  arches  by  the  inosculation  of  their 
larger  branches;  from  these  are  developed  secondary  arches,  and 
from  the  latter  a  third  series  of  arches,  from  which  the  branches 
arise  which  are  distributed  to  the  coats  of  the  intestine.  From  the 
middle  branches  a  fourth  and  sometimes  even  a  fifth  series  of  arches 
is  produced.  By  means  of  these  arches  a  direct  communication  is 
established  between  all  the  branches  given  off  from  the  convexity  of 
the  superior  mesenteric  artery;  the  superior  branches  moreover 
supply  the  pancreas  and  duodenum,  and  inosculate  with  the  pan- 
creatico-duodenalis  ;  and  the  inferior  with  the  ileo-colica. 

The  Ileo-colica  artery  is  the  last  branch  given  off  from  the  conca- 
vity of  the  superior  mesenteric.  It  descends  to  the  right  iliac  fossa, 
and  divides  into  branches  which  communicate  and  form  arches, 
from  which  branches  are  distributed  to  the  termination  of  the  ileum, 
the  csecum,  and  the  commencement  of  the  colon.  This  artery  inos- 
culates on  the  one  hand  with  the  last  branches  of  the  vasa  intestini 
tenuis,  and  on  the  other  with  the  colica  dextra. 

The  Colica  dextra  arises  from  about  the  middle  of  the  concavity 
of  the  superior  mesenteric,  and  divides  into  branches  which  form 
arches,  and  are  distributed  to  the  ascending  colon.  Its  descending 
branches  inosculate  with  the  ileo-colica,  and  the  ascending  with  the 
colica  media. 

The  Colica  media  arises  from  the  upper  part  of  the  concavity  of 
the  superior  mesenteric,  and  passes  forwards  between  the  layers  of 
the  transverse  mesocolon,  where  it  forms  arches,  and  is  distributed 
to  the  transverse  colon.  It  inosculates  on  the  right  with  the  colica 
dextra ;  and  on  the  left  with  the  colica  sinistra,  a  branch  of  the  in- 
ferior mesenteric  artery. 

The  Spermatic  Arteries  are  two  small  vessels  which  arise  from 
the  front  of  the  aorta  below  the  superior  mesenteric  ;  from  this  origin 
each  artery  passes  obliquely  outwards,  and  accompanies  the  corre- 
sponding ureter  along  the  front  of  the  psoas  muscle  to  the  border  of 
the  pelvis,  where  it  is  in  relation  with  the  external  iliac  artery.  It 
is  then  directed  outwards  to  the  internal  abdominal  ring,  and  follows 
the  course  of  the  spermatic  cord  along  the  spermatic  canal,  and 
through  the  scrotum  to  the  testicle,  to  which  it  is  distributed.  The 
right  spermatic  artery  lies  in  front  of  the  vena  cava,  and  both  ves- 
sels are  accompanied  by  their  corresponding  veins  and  by  the  sper- 
matic plexuses  of  nerves. 

The  spermatic  arteries  in  the  female  descend  into  the  pelvis  and 
pass  between  the  two  layers  of  the  broad  ligaments  of  the  uterus,  to 
be  distributed  to  the  ovaries.  Fallopian  tubes,  and  round  ligaments; 
along  the  latter  they  are  continued  to  the  inguinal  canal  and  labium 
at  each  side. 

They  inosculate  with  the  uterine  arteries. 


INFERIOR  MESENTERIC  ARTERY". 


329 


The  Inferior  Mesenteric  Artery,  smaller  than  the  superior, 
arises  from  the  abdominal  aorta,  about  two  inches  below  the  origin 
of  that  vessel,  and  descends  between  the  layers  of  the  left  mesocolon, 
to  the  left  iliac  fossa,  where  it  divides  into  three  branches : 

Colica  sinistra,  superior, 

Sigmoidece,  or  colica  sinistra  media  and  inferior, 

Superior  hsemorrhoidal. 

The  Colica  sinistra  is  distributed  to  the  descending  colon,  and 
ascends  to  inosculate  with  the  colica  media.  This  is  the  largest 
arterial  inosculation  in  the  body. 

Fig.  127. 


Fig.  127.  Tlie  distribution  and  branches  of  the  inferior  mesenteric  artery.  1,  1. 
The  superior  artery  with  its  brandies  and  the  small  intestines  turned  over  to  the  right 
side.  2,  The  csecum  and  appendix  caeci.  3.  The  ascending  colon.  4.  The  transverse 
colon  raised  upwards.  5.  The  descending  colon.  6.  Its  sigmoid  flexure.  7.  The 
rectum.  8.  The  aorta.  9.  The  inferior  mesenteric  artery.  10.  The  colica  sinistra, 
inosculating  with  11.  The  colica  media,  a  branch  of  the  superior  mesenteric  artery. 
12,  12.  Sigmoid  branches.  13.  The  superior  hsemorrhoidal  artery.  14.  The  pancreas. 
15.  The  descending  portion  of  the  duodenum. 

28* 


330  EENAL  ARTERIES LUMBAR  ARTERIES. 

The  SigmoidecB  are  several  large  branches  which  are  distributed 
to  the  sigmoid  flexure  of  the  descending  colon.  They  form  arches, 
and  inosculate  above  with  the  colica  sinistra,  and  below  with  the 
superior  hasmorrhoidal  artery. 

The  Superior  hcsmorrhoidal  artery  is  the  continuation  of  the 
inferior  mesenteric.  It  crosses  the  ureter  and  common  iliac  artery 
of  the  left  side,  and  descends  between  the  two  layers  of  the  meso- 
rectum  as  far  as  the  middle  of  the  rectum  to  which  it  is  distributed, 
anastomosing  with  the  middle  and  external  hsemorrhoidal  arteries. 

The  Supra-Renal  are  two  small  vessels  which  arise  from  the 
aorta  immediately  above  the  renal  arteries,  and  are  distributed  to 
the  supra-renal  capsules.  They  are  sometimes  branches  of  the 
phrenic  or  of  the  renal  arteries. 

The  Renal  Arteries  (emulgent)  are  two  large  trunks  given  off 
from  the  sides  of  the  aorta  immediately  below  the  superior  mesen- 
teric artery;  the  right  is  longer  than  the  left  on  account  of  the  posi- 
tion of  the  aorta,  and  passes  behind  the  vena  cava  to  the  kidney  of 
that  side.  The  left  is  somewhat  higher  than  the  right.  They  divide 
into  several  large  branches  previously  to  entering  the  kidney,  and 
ramify  very  minutely  in  its  vascular  portion.  The  renal  arteries 
supply  several  small  branches  to  the  supra-renal  capsules. 

The  Lumbar  Arteries  correspond  with  the  intercostals  in  the 
chest ;  they  are  four  or  five  in  number  on  each  side,  and  curve 
around  the  bodies  of  the  lumbar  vertebrae  beneath  the  psoas  muscles, 
and  divide  into  two  branches ;  one  of  which  passes  backwards 
between  the  transverse  processes  and  is  distributed  to  the  vertebras 
and  spinal  cord  and  to  the  muscles  of  the  back,  whilst  the  other 
takes  its  course  behind  the  quadratus  lumborum  muscle  and  supplies 
the  abdominal  muscles.  The  first  lumbar  artery  runs  along  the 
lower  border  of  the  last  rib,  and  the  last  along  the  crest  of  the  ilium. 
In  passing  between  the  psoas  muscles  and  the  vertebrae,  they  are 
protected  by  a  series  of  tendinous  arches,  which  defend  them  and 
the  communicating  branches  of  the  sympathetic  nerve  from  pressure 
during  the  action  of  the  muscle. 

The  Sacra  Media  arises  from  the  posterior  part  of  the  aorta  at 
its  bifurcation,  and  descends  along  the  middle  of  the  anterior  surface 
of  the  sacrum  to  the  first  piece  of  the  coccyx,  where  it  terminates 
by  inosculating  with  the  lateral  sacral  arteries.  It  distributes  branches 
to  the  rectum  and  anterior  sacral  nerves,  and  inosculates  on  either 
side  with  the  lateral  sacral  arteries. 

Varieties  in  the  Branches  of  the  Abdominal  Aorta. — The  phrenic 
arteries  are  very  rarely  both  derived  from  the  aorta.  One  or  both 
may  be  branches  of  the  coeliac  axis  ;  one  may  proceed  from  the 
gastric  artery,  from  the  renal,  or  from  the  upper  lumbar  artery. 
There  are  occasionally  three  or  more  phrenic  arteries.  The  coeliac 
axis  is  very  variable  in  length,  and  gives  off  its  branches  irregularly. 
There  are  sometimes  two  or  even  three  hepatic  arteries,  one  of 
which  may  be  derived  from  the  gastric  or  even  from  the  superior 
mesenteric.  The  colica  media  is  sometimes  derived  from  the  hepatic 


COMMON  ILIAC  AETERIES.  33  1 

artery.  The  spermatic  arteries  are  very  variable  both  in  origin  and 
number.  The  right  spermatic  may  be  a  branch  of  the  renal  artery, 
and  the  left  a  branch  of  the  inferior  mesenteric.  The  supra-renal 
arteries  may  be  derived  from  the  phrenic  or  renal  arteries.  The 
irenal  arteries  present  several  varieties  in  number  ;  there  may  be 
three  or  even  four  arteries  on  one  side  and  one  only  on  the  other. 
When  there  are  several  renal  arteries  on  one  side,  one  may  arise 
from  the  common  iliac  artery,  from  the  front  of  the  aorta  near  its 
lower  part,  or  from  the  internal  iliac. 

COMMON     ILIAC     ARTERIES. 

The  abdominal  aorta  divides  opposite  the  fourth  lumbar  vertebrae 
into  the  two  common  iliac  arteries.  Sometimes  the  bifurcation  takes 
place  as  high  as  the  third,  and  occasionally  as  low  as  the  fifth  lum- 
bar vertebra.  The  common  iliac  arteries  are  about  two  inches  and 
a  half  in  length ;  they  diverge  from  the  termination  of  the  aorta,  and 
pass  downwards  and  outwards  on  each  side  to  the  margin  of  the 
pelvis  opposite  the  sacro-iliac  symphysis,  where  they  divide  into  the 
internal  and  external  iliac  arteries.  In  old  persons  the  common  iliac 
arteries  are  more  or  less  dilated  and  curved  in  their  course. 

The  Right  common  iliac  is  somewhat  longer  than  the  left  and 
forms  a  more  obtuse  angle  with  the  termination  of  the  aorta ;  the 
angle  of  bifurcation  is  greater  in  the  female  than  in  the  male. 

Relations. — The  relations  of  the  two  arteries  are  different  on  the 
two  sides  of  the  body.  The  right  common  iliac  is  in  relation  in 
front  with  the  peritoneum,  and  is  crossed  at  its  bifurcation  by  the 
ureter.  It  is  in  relation  posteriorly  with  the  two  common  iliac  veins, 
and  externally  with  the  psoas  magnus.  The  left  is  in  relation  in 
front  with  the  peritoneum,  and  is  crossed  by  the  rectum  and  superior 
hsemorrhoidal  artery,  and  at  its  bifurcation  by  the  ureter.  It  is  in 
relation  behind  with  the  left  common  iliac  vein,  and  externally  with 
the  psoas  magnus. 

INTERNAL     ILIAC    ARTERY. 

The  Internal  Iliac  Artery  is  a  short  trunk,  varying  in  length  from 
an  inch  to  two  inches.  It  descends  obliquely  to  a  point  opposite  the 
upper  margin  of  the  great  sacro-ischiatic  foramen,  where  it  divides 
into  an  anterior  and  a  posterior  trunk. 

Relations. — This  artery  rests  externally  upon  the  sacral  plexus 
and  upon  the  origin  of  the  pyriformis  muscle;  posteriorly  it  is  in 
relation  with  the  internal  iliac  vein,  and  anteriorly  with  the  ureter. 

Branches. — The  branches  of  the  anterior  trunk  are  the — 

Umbilical,  Ischiatic, 

Middle  vesical.  Internal  pudic. 

Middle  hoemorrhoidal, 

And  in  the  female  the — 

Uterine,  Vaginal. 


332 


INTERNAL  ILIAC  ARTERY. 


And  of  the  posterior  trunk  the — 

IHo-himbar,  Lateral  sacral, 

Obturator,  Gluteal. 

The  umbilical  artery  is  the  commencement  of  the  fibrous  cord 
into  which  the  umbilical  artery  of  the  foetus  is  converted  after  birth. 
In  after  life,  the  cord  remains  pervious  for  a  short  distance,  and  con- 
stitutes the  umbilical  artery  of  the  adult,  from  which  the  superior 
vesical  artery  is  given  off  to  the  fundus  and  anterior  aspect  of  the 
bladder.  The  cord  may  be  traced  forwards  by  the  side  of  the 
fundus  of  the  bladder  to  near  its  apex,  whence  it  ascends  by  the 
side  of  the  linea  alba  and  urachus  to  the  umbilicus. 

Fig.  128. 


The  Middle  vesical  artery  is  generally  a  branch  of  the  umbilical, 
and  sometimes  of  the  internal  iliac.  It  is  somewhat  larger  than  the 
superior  vesical,  and  is  distributed  to  the  posterior  part  of  the  body 
of  the  bladder,  the  vesiculse  seminales,  and  prostate  gland. 

The  Middle  licemorrhoidal  artery  is  as  frequently  derived  from  the 
ischiatic  or  internal  pudic  as  from  the  internal  iliac.  It  is  of  variable 
size,  and  is  distributed  to  the  rectum,  base  of  the  bladder,  vesiculse 
seminales,  and  prostate  gland ;  and  inosculates  with  the  superior 
and  external  hsemorrhoidal  arteries. 


Fig.  128.  The  distribution  and  branches  of  the  iliac  arteries.  1.  The  aorta.  2.  The 
left  common  iliac  artery.  3.  The  external  iliac.  4.  The  epigastric  artery.  5.  The 
circumflexa  ilii.  6.  The  internal  iliac  artery.  7.  Its  anterior  trunk.  8.  Its  posterior 
trunk.  9.  The  umbilical  artery  giving  off  (10)  the  superior  vesical  artery.  After  the 
origin  of  this  branch,  the  umbilical  artery  becomes  converted  into  a  fibrous  cord — the 
umbilical  ligament.  11.  The  internal  pudic  artery  passing  behind  the  spine  of  the 
ischium  (12)  and  lesser  sacro-ischiatic  ligament.  13.  The  middle  hajmorrhoidal 
artery.  14.  The  ischiatic  artery,  also  passing  behind  the  anterior  sacro-ischiatic 
ligament  to  escape  from  tlie  pelvis.  15.  Its  inferior  vesical  branch.  16.  The  ilio- 
lumbar, the  first  branch  of  the  posterior  trunk  (8)  ascending  to  inosculate  with  the 
circumflexa  ilii  artery  (.'))  and  form  an  arch  along  the  crest  of  the  ilium.  17.  The 
obturator  artery.  18.  The  lateral  sacral.  19.  The  gluteal  artery  escaping  from  the 
pelvis  through  the  upper  part  of  the  great  sacro-ischiatic  foramen.  20.  The  sacra 
media.     21.  The  right  common  iliac  artery  cut  short.     22.  The  femoral  artery. 


fSCHIATIC  AETERY. 


333 


The  IscHiATic  Artery  is  the  larger  of  the  two  terminal  branches 
of  the  anterior  division  of  the  internal  iliac.  It  passes  downwards 
between  the  posterior  border  of  the  levator  ani,  and  the  pyriformis, 
resting  upon  the  sacral  plexus  of  nerves  and  lying  behind  the  internal 
pudic  artery,  to  the  lower  border  of  the  great  ischiatic  notch,  where 
it  escapes  from  the  pelvis  below  the  pyrifomis  muscle.  It  then 
descends  in  the  space  between  the  trochanter  major  and  the  tube- 
rosity of  the  ischium  in  company  with  the  ischiatic  nerves,  and 
divides  into  branches. 

Fig.  129. 


Its  branches  within  the  pelvis  are  the  inferior  hcBmorrhoidal,  which 
supplies  the  rectum  conjointly  with  the  middle  hsemorrhoidal  and 
sometimes  takes  the  place  of  that  artery ,*and  the  inferior  vesical, 
which  is  distributed  to  the  base  and  neck  of  the  bladder,  the  vesi- 
culse  seminales,  and  prostate  gland.  The  branches  external  to  the 
pelvis,  are  four  in  number — coccygeal,  inferior  gluteal,  comes  nervi 
ischiatici,  and  muscular  branches. 

The  Coccygeal  branch  pierces  the  great  sacro-ischiatic  ligament, 
and  is  distributed  to  the  coccygeus  and  levator  ani  muscles,  and  to 
the  integument  around  the  anus  and  coccyx. 


Fig.  129.  The  arteries  of  the  perineum  ;  on  the  right  side  the  superficial  arteries  are 
seen,  and  on  the  left  the  deep.  1.  The  penis,  consisting  of  corpus  spongiosum  and 
corpus  cavernosum.  The  crus  penis  on  the  left  side  is  cut  through.  2.  The  accele- 
ratores  urinae  muscles,  enclosing  the  bulbous  portion  of  the  corpus  spongiosum.  3. 
The  erector  penis,  spread  out  upon  the  crus  penis  of  the  right  side.  4.  The  anus, 
surrounded  by  the  sphincter  ani  muscle.  5.  The  ramus  of  the  ischium  and  os  pubis. 
6.  The  tuberosity  of  the  ischium.  7.  The  lesser  sacro-ischiatic  ligament,  attached  by 
its  small  extremity  to  the  spine  of  the  ischium.  8.  The  coccyx.  9.  The  internal  pudi(^ 
artery,  crossing  the  spine  of  the  isciiium,  and  entering  the  perineum.  10.  Inferior 
hsemorrhoidal  branch.  11.  The  superficialis  perinei  artery,  giving  off  a  small  branch, 
transvevsalis  perinei,  upon  the  transversus  perinei  muscle.  13.  The  same  artery  on  the 
left  side  cut  off.  13.  The  artery  of  the  bulb.  14.  The  two  terminal  branches  of  the 
internal  pudic  artery  ;  one  is  seen  entering  the  divided  extremity  of  the  crus  penis,  the 
artery  of  the  corpus  cavernosum ;  the  other,  the  dorsalis  penis,  ascends  upon  the  dorsum 
of  the  organ. 


334  INTERNAL  PUDIC  ARTEKr. 

The  Inferior  gluteal  branches  supply  the  gluteus  maximus  muscle. 

The  Comes  nervi  ischiatici  is  a  small  but  regular  branch,  which 
accompanies  the  great  ischiatic  nerve  to  the  lower  part  of  the  thigh. 

The  Muscular  branches  supply  the  muscles  of  the  posterior  part 
of  the  hip  and  thigh,  and  inosculate  with  the  internal  and  external 
circumflex  arteries,  with  the  obturator,  and  with  the  superior  per- 
forating artery. 

The  Interival  Pudic  Artery,  the  other  terminal  branch  of  the 
anterior  trunk  of  the  internal  iliac,  descends  in  front  of  the  ischiatic 
artery  to  the  lower  border  of  the  great  ischiatic  foramen.  It  emerges 
from  the  pelvis  through  the  great  sacro-ischiatic  foramen  below  the 
pyriformis  muscle,  crosses  the  spine  of  the  ischium,  and  re-enters 
the  pelvis  through  the  lesser  sacro-ischiatic  foramen  ;  it  then  crosses 
the  internal  obturator  muscle  to  the  ramus  of  the  ischium,  being 
situated  at  about  an  inch  from  the  margin  of  the  tuberosity,  and 
bound  down  by  the  obturator  fascia ;  it  next  ascends  the  ramus  of 
the  ischium,  enters  between  the  two  layers  of  the  deep  perineal 
fascia  lying  along  the  border  of  the  ramus  of  the  os  pubis,  and  at 
the  symphysis,  pierces  the  anterior  layer  of  the  deep  perineal  fascia, 
and  very  much  diminished  in  size  reaches  the  dorsum  of  the  penis, 
along  which  it  runs,  supplying  that  organ  under  the  name  of  the 
dorsalis  penis. 

Branches. — The  branches  of  the  internal  pudic  artery  within  the 
pelvis  are  several  small  ramuscules  to  the  base  of  the  bladder,  the 
vesiculffi  seminales,  and  the  prostate  gland  ;  and  the  hcp.morrhoidal 
branch  which  supplies  the  middle  of  the  rectum,  and  frequently  takes 
the  place  of  the  middle  haemorrhoidal  branch  of  the  internal  iliac. 

The  branches,  external  to  the  pelvis,  are  the 

Inferior  hsemorrhoidal, 
Superficialis  perinei, 

Transversalis  perinei, 
Arteria  bulbosa, 
Arteria  corporis  cavernosi, 
Arteria  dorsalis  penis. 

The  Inferior  hcemorrhoidal  artery  is  given  off  by  the  internal  pudic 
while  behind  the  tuberosity  of  the  ischium.  It  is  distributed  to  the 
anus,  and  to  the  muscles,  the  fascia,  and  the  integument  in  the  anal 
region  of  the  perineum. 

The  Superficial  perineal  artery  is  given  off  near  the  attachment 
of  the  crus  penis  ;  it  pierces  the  connecting  layer  of  the  superficial 
and  deep  perineal  fascia,  and  runs  forwards  across  the  transversus 
perinei  muscle,  and  along  the  groove  between  the  accelerator  urinse 
and  erector  penis  to  the  septum  scroti,  upon  which  it  ramifies  under 
the  name  of  arteria  sepli.  It  distributes  branches  to  the  scrotum, 
and  to  the  perineum  in  its  course  forwards.  One  of  the  latter,  larger 
than  the  rest,  crosses  the  perineum,  resting  on  the  transversus  peri- 
nei muscle,  and  is  named  the  transversalis  perinei. 


UTERINE,  VAGINAL,  AND  OBTURATOR  ARTERIES.  335 

The  Artery  of  ike  bulb  is  given  off  from  the  pudic  nearly  opposite 
the  opening  for  the  transmission  of  the  urethra  ;  it  passes  nearly 
transversely  inwards  between  the  two  layers  of  the  deep  perineal 
fascia,  and  pierces  the  anterior  layer  to  enter  the  corpus  spongiosum 
at  its  bulbous  extremity.   It  is  distributed  to  the  corpus  spongiosum. 

The  Artery  of  the  corpus  cavernosum  pierces  the  crus  penis,  and 
runs  forward  in  the  interior  of  the  corpus  cavernosum,  by  the  side 
of  the  septum  pectiniforme.  It  ramifies  in  the  parenchyma  of  the 
venous  structure  of  the  corpus  cavernosum. 

The  Dorsal  artery  of  the  penis  ascends  between  the  two  crura  and 
symphysis  pubis  to  the  dorsum  penis,  and  runs  forward  through  the 
suspensory  ligament  in  the  groove  of  tlie  corpus  cavernosum  to  the 
glans,  distributing  branches  in  its  course  to  the  body  of  the  organ 
and  to  the  integument. 

The  Internal  pudic  artery  in  the  female  is  smaller  than  in  the 
male;  its  branches,  with  their  distribution,  are  in  principle  the  same. 
The  superficial  perineal  artery  supplies  the  analogue  of  the  lateral 
half  of  the  scrotum,  viz.  the  greater  labium.  The  artery  of  the  bulb 
supplies  the  meatus  urinarius,  and  the  vestibule;  the  artery  of  the 
corpus  cavernosum,  the  cavernous  body  of  the  clitoris,  and  the  arte- 
ria  dorsalis  clitoridis,  the  dorsum  of  that  organ. 

The  Uterine  and  Vaginal  arteries  of  the  female  are  derived 
either  from  the  internal  iliac,  or  from  the  umbilical,  internal  pudic, 
or  ischiatic  arteries.  The  former  are  very  tortuous  in  their  course, 
and  ascend  between  the  layers  of  the  broad  ligament,  to  be  distri- 
buted to  the  uterus.  The  latter  ramify  upon  the  exterior  of  the 
vagina,  and  supply  its  mucous  membrane. 

Branches  of  the  posterior  trunk. 

The  llio-lumbar  artery  ascends  beneath  the  external  iliac  vessels 
and  psoas  muscle,  to  the  posterior  part  of  the  crest  of  the  ilium, 
"where  it  divides  into  two  branches,  a  lumbar  branch,  which  supplies 
the  psoas  and  iliacus  muscles,  and  sends  a  ramuscuie  through  the 
fifth  intervertebral  foramen  to  the  spinal  cord  and  its  membranes; 
and  an  iliac  branch,  which  passes  along  the  crest  of  the  ilium,  dis- 
tributing branches  to  the  iliacus  and  abdominal  muscles,  and  inos- 
culating with  the  lumbar  and  gluteal  arteries,  and  with  the  circum- 
flexa  ilii. 

The  Obturator  Artery  is  exceedingly  variable  in  point  of 
origin  ;  it  generally  proceeds  from  the  posterior  trunk  of  the  internal 
iliac  artery,  and  passes  forwards  a  little  below  the  brim  of  the  pelvis 
to  the  upper  border  of  the  obturator  foramen.  It  there  escapes 
from  the  pelvis  through  a  tendinous  arch  formed  by  the  obturator 
membrane,  and  divides  into  two  branches  ;  an  internal  branch, 
which  curves  inwards  around  the  bony  margin  of  the  obturator 
foramen,  between  the  obturator  exiernus  muscle  and  the  ramus  of 
the  ischium,  and  distributes  branches  to  the  obturator  muscles,  the 
pectineus,  the  adductor  muscles,  and  to  the  organs  of  generation, 


336  GLUTEAL  ARTERY. 

and  inosculates  with  the  internal  circumflex  artery.  And  an  external 
branch,  which  pursues  its  course  along  the  outer  margin  of  the 
obturator  foramen  to  the  space  between  the  gemellus  inferior  and 
quadratus-  femoris,  where  it  inosculates  with  the  ischiatic  artery. 
In  its  course  backwards  it  anastomoses  with  the  internal  circumflex, 
and  sends  a  branch  through  the  notch  in  the  acetabulum  to  the  hip- 
joint.  Within  the  pelvis  the  obturator  artery  gives  off  a  branch  to 
the  iliacus  muscle,  and  a  small  ramuscule  which  inosculates  with 
the  epigastric  artery. 

The  Lateral  Sacral  Arteries  are  generally  two  in  number  on 
each  side;  superior  and  inferior.  The  superior  passes  inwards  to 
the  first  sacral  foramen,  and  is  distributed  to  the  contents  of  the 
spinal  canal,  from  which  it  escapes  by  the  posterior  sacral  foramen, 
and  supplies  the  integument  on  the  dorsum  of  the  sacrum.  The 
inferior  passes  down  by  the  side  of  the  anterior  sacral  foramina  to  the 
coccyx ;  it  first  pierces  and  then  rests  upon  the  origin  of  the  pyri- 
formis,  and  sends  branches  into  the  sacral  canal  to  supply  the  sacral 
nerves.  Both  arteries  inosculate  with  each  other  and  with  the  sacra 
media. 

The  Gluteal  Artery  is  the  continuation  of  the  posterior  trunk 
of  the  internal  iliac :  it  passes  backwards  between  the  lumbo-sacral 
and  first  lumbar  nerve  through  the  upper  part  of  the  great  sacro- 
ischiatic  foramen,  and  above  the  pyriformis  muscle,  and  divides 
into  three  branches — superficial,  deep  superior,  and  deep  inferior. 

The  Superficial  branch  is  directed  forwards  between  the  gluteus 
maximus  and  medius,  and  divides  into  numerous  branches,  which 
are  distributed  to  the  upper  part  of  the  gluteus  maximus  and  to  the 
integument  of  the  gluteal  region. 

The  Deep  superior  branch  passes  along  the  superior  curved  line 
of  the  ilium,  between  the  gluteus  medius  and  minimus  to  the  ante- 
rior superior  spinous  process,  where  it  inosculates  with  the  superfi- 
cial circumflexa  ilii  and  external  circumflex  artery.  There  are 
frequently  two  arteries  which  follow  this  course. 

The  Deep  inferior  branches  are  several  large  arteries  which 
cross  the  gluteus  minimus  obliquely  to  the  trochanter  major,  where 
they  inosculate  with  branches  of  the  external  circumflex  artery,  and 
send  branches  through  the  gluteus  minimus  to  supply  the  capsule  of 
the  hip-joint. 

Varieties  in  the  Branches  of  the  Internal  Iliac. — The  most  impor- 
tant of  the  varieties  occurring  among  these  branches  is  the  origin 
of  the  dorsal  artery  of  the  penis  from  the  internal  iliac  or  ischiatic. 
The  artery  in  this  case  passes  forwards  by  the  side  of  the  prostate 
gland,  and  through  the  upper  part  of  the  deep  perineal  fascia.  It 
would  be  endangered  in  the  operation  for  lithotomy.  The  dorsal 
artery  of  the  penis  is  sometimes  derived  from  the  obturator,  and 
sometimes  from  one  of  the  external  pudic  arteries.  The  artery  of 
the  bulb,  in  its  normal  course,  passes  almost  transversely  inwards  to' 
the  corpus  spongiosum.  Occasionally,  however,  it  is  so  oblique  in 
its  direction  as  to  render   its  division  in  lithotomy  unavoidable. 


EXTERNAL  ILIAC  ARTERY.  337 

The  obturator  artery  may  be  very  small  or  altogether  wanting,  its 
place  being  supplied  by  a  branch  from  the  external  iliac  or  epigas- 
tric. 

EXTERNAL     ILIAC     ARTERY. 

The  external  iliac  artery  of  each  side  passes  obliquely  downwards 
along  the  inner  border  of  the  psoas  muscle,  from  opposite  the  sacro- 
iliac symphysis  to  the  femoral  arch,  where  it  becomes  the  femoral 
artery. 

Relations. — It  is  in  relation  in  front  with  the  spermatic  vessels, 
the  peritoneum,  and  a  thin  layer  of  fascia,  derived  from  the  iliac 
fascia,  which  surrounds  the  artery  and  vein.  At  its  commence- 
ment it  is  crossed  by  the  ureter,  and  near  its  termination  by  the 
crural  branch  of  thegenito-crural  nerve  and  the  circumflexa  ilii  vein. 
Externally  it  lies  against  the  psoas  muscle,  from  which  it  is  sepa- 
rated by  the  iliac  fascia;  and  fosteriorly  it  is  in  relation  with  the 
external  iliac  vein,  which,  at  the  femoral  arch,  becomes  placed  to 
its  inner  side.  The  artery  is  surrounded  throughout  the  whole  of 
its  course  by  lymphatic  vessels  and  glands. 

Branches. — Besides  several  small  branches  which  supply  the 
glands  surrounding  the  artery,  the  external  iliac  gives  off  two 
branches,  the — 

Epigastric, 
Circumflexa  ilii. 

The  Epigastric  artery  arises  from  the  external  iliac  near  to  Pou- 
part's  ligament ;  and  passing  forwards  between  the  peritoneum  and 
transversalis  fascia,  ascends  obliquely  to  the  border  of  the  sheath  of 
the  rectus.  It  enters  the  sheath  near  to  its  lower  third,  passes 
upwards  behind  the  rectus  muscle,  to  which  it  is  distributed,  and 
in  the  substance  of  that  muscle  it  inosculates  near  the  ensiform 
cartilage  with  the  termination  of  the  internal  mammary  artery.  It 
lies  internally  to  the  internal  abdominal  ring,  and  immediately  above 
the  femoral  ring,  and  is  crossed  near  its  origin  by  the  vas  deferens 
in  the  male,  and  by  the  round  ligament  in  the  female. 

The  only  branches  of  the  epigastric  artery  worthy  of  distinct 
notice  are  the  Cremasteric,  which  accompanies  the  spermatic  cord 
and  supplies  the  cremaster  muscle  ;  and  the  ramusculus  which  inos- 
culates with  the  obturator  artery. 

The  Epigastric  artery  forms  a  projection  of  the  peritoneum  w^hich 
divides  the  iliac  fossa  into  an  internal  and  an  external  portion ;  it  is 
from  the  former  that  direct  inguinal  hernia  issues,  and  from  the 
latter,  oblique  inguinal  hernia. 

The  Circurnflexa  ilii  arises  from  the  outer  side  of  the  external 
iliac,  nearly  opposite  to  the  epigastric  artery.  It  ascends  obliquely 
along  Poupart's  ligament,  and  curving  around  the  crest  of  the  ilium 
between  the  attachments  of  the  internal  oblique  and  transversalis 

29 


338 


FEMORAL  AKTERY. 


Fig.  130. 


muscle,  inosculates  with  the  ilio-lumbar  and  inferior  lumbar  artery. 
Opposite  the  anterior  superior  spinous  process 
of  the  ilium  it  gives  off  a  large  ascending 
branch,  whicfi  passes  upwards  between  the 
internal  oblique  and  transversalis,  and  divides 
into  numerous  branches  which  supply  the  ab- 
dominal muscles,  and  inosculates  with  the  infe- 
rior intercostal  and  with  the  lumbar  arteries. 
Varieties  in  the  branches  of  the  external 
iliac. — The  epigastric  artery  not  unfrequently 
gives  off  the  obturator,*  which  descends  in 
contact  with  the  external  iliac  vein,  to  the 
obturator  foramen.  In  this  situation  the  artery 
would  lie  to  the  outer  side  of  the  femoral 
ring,  and  would  not  be  endangered  in  the 
operation  for  dividing  the  stricture  of  femoral 
hernia.  But  occasionally  the  obturator  passes 
along  the  free  margin  of  Gimbernat's  liga- 
ment in  its  course  to  the  obturator  foramen, 
and  would  completely  encircle  the  neck  of 
the  hernial  sac  ;  a  position  in  which  it  could 
scarcely  escape  the  knife  of  the  operator. 

In  a  preparation  in  my  anatomical  collec- 
tion the  branch  of  communication  between 
the  epigastric  and  obturator  arteries  is  very 
much  enlarged,  and  takes  this  dangerous 
course. 

FEMORAL     ARTERV. 

Emerging   from   beneath   Poupart's  liga- 
ment, the  external    iliac    artery  enters   the 
thigh  and  becomes  the  femoral.     The  femoral  artery  passes  down 

Fig.  130.  A  view  of  the  anterior  and  inner  aspect  of  the  thigh,  showing  the  course 
and  branches  of  the  femoral  artery.  1.  The  lower  part  of  the  aponeurosis  of  the  ex- 
ternal  oblique  muscle;  its  inferior  margin  is  Poupart's  ligament.  2.  The  external 
abdominal  ring.  3,3.  The  upper  and  lower  part  of  the  sartorius  muscle;  its  middle 
portion  having  been  removed.  4.  The  rectus.  5.  The  vastus  internus.  6.  The  patella. 
7.  The  iliacus  and  psoas ;  the  latter  being  nearest  the  artery.  8.  The  pectineus.  9. 
The  adductor  longus.  10.  The  tendinous  canal  for  the  femoral  artery  formed  by  the 
adductor  rnagnus,  and  vastus  internus  muscles.  11.  The  adductor  magnus.  12.  The 
gracilis.  13.  The  tendon  of  the  semi-tcndinosus.  14.  The  femoral  artery.  15.  The 
superficial  circumflexa  ilii  artery  taking  its  course  along  the  line  of  Poupart's  ligament, 
to  the  crest  of  the  ilium.  2.  The  superficial  epigastric  artery.  16.  The  two  external 
pudic  arteries,  superficial  and  deep.  17.  The  profunda  artery  giving  off  18,  its  external 
circumflex  branch  ;  and  lower  down  the  three  perforantes.  A  small  bond  of  (he  internal 
circumflex  artery  (8)  is  seen  behind  the  inner  marfjin  of  the  femoral,  just  below  the 
deep  external  pudic  artery.  19.  The  anastomotic!  magna,  descending  to  the  knee, 
upon  which  it  ramifies  (6). 

*  The  proportion  in  which  high  division  of  the  obturator  artery  from  the  epigastric 
occurs,  is  stated  1o  be  one  in  three.  In  two  hundred  and  fifty  subjects  examined  by 
(;iof|uct  with  a  view  to  ascertain  how  frequently  the  high  division  took  place,  he  found 
the  obturator  arising  from  the  epigastric  on  both  sides  one  hundred  and  fifty  times;  on 
one  side  twenty-eight  times,  and  six  times  it  arose  from  the  femoral  artery. 


FEMORAL  ARTERY.  339 

the  inner  side  of  the  thigh,  from  Poupart's  ligament,  at  a  point  mid- 
way between  the  anterior  superior  spinous  process  of  the  iUum  and 
the  symphysis  pubis,  to  the  hole  in  the  adductor  magnus,  at  the  junc- 
tion of  the  middle  with  the  inferior  third  of  the  thigh,  where  it 
becomes  the  popliteal  artery. 

The  femoral  artery  and  vein  are  enclosed  in  a  strong  sheath, 
femoral  or  crural  canal,  which  is  formed  for  the  greater  part  of  its 
extent  by  fibrous  and  cellular  tissue,  and  by  a  process  of  fascia  sent 
inwards  from  the  fascia  lata.  Near  Poupart's  ligament  this  sheath 
is  much  larger  than  the  vessels  it  contains,  and  is  continuous  with 
the  fascia  transversalis,  and  iliac  fascia.  If  the  sheath  be  opened 
at  this  point,  the  artery  will  be  seen  to  be  situated  in  contact  with 
the  outer  wall  of  the  sheath.  The  vein  lies  next  to  the  artery,  being 
separated  from  it  by  a  fibrous  septum,  and  between  the  vein  and 
the  inner  wall  of  the  sheath,  and  divided  from  the  vein  by  another 
thin  fibrous  septum,  is  a  triangular  interval,  into  which  the  sac  is 
protruded  in  femoral  hernia.  This  space  is  occupied  in  the  normal 
state  of  the  parts  by  loose  cellular  tissue,  and  by  lymphatic  vessels 
which  pierce  the  inner  wall  of  the  sheath  to  make  their  way  to  a 
gland,  situated  in  the  femoral  ring. 

Relations. — The  upper  third  of  the  femoral  artery  is  superficial, 
being  covered  only  by  the  integument,  inguinal  glands,  and  by  the 
superficial  and  deep  fasciae.  The  lower  two-thirds  are  covered  by 
the  sartorius  muscle.  To  its  outer  side  the  artery  is  first  in  relation 
with  the  psoas,  next  with  the  rectus,  and  then  with  the  vastus  in- 
ternus.  Behind  it  rests  upon  the  inner  border  of  the  psoas  muscle; 
it  is  next  separated  from  the  pectineus  by  the  femoral  vein,  profunda 
vein  and  artery,  and  then  lies  on  the  adductor  longus,  to  its  termi- 
nation :  near  the  lower  border  of  the  adductor  longus,  it  is  placed 
in  an  aponeurotic  canal,  formed  by  an  arch  of  tendinous  fibres, 
thrown  from  the  border  of  the  adductor  longus,  and  the  border  of 
the  opening  in  the  adductor  magnus,  to  the  side  of  the  vastus  in- 
ternus.  To  its  inner  side  it  is  in  relation  at  its  upper  part  with  the 
femoral  vein,  and  lower  down  with  the  pectineus,  the  adductor 
longus,  and  sartorius. 

The  immediate  relations  of  the  artery  are  the  femoral  vein,  and 
two  saphenous  nerves.  The  vein  at  Poupart's  ligament  lies  to  the 
inner  side  of  the  artery;  but  lower  down  gets  altogether  behind  it. 
The  short  saphenous  nerve  lies  to  the  outer  side,  and  somewhat 
upon  the  sheath  for  the  lower  two-thirds  of  its  extent ;  and  the  long 
saphenous  nerve  is  situated  within  the  sheath  for  the  same  extent. 


340  FEMOKAIi  AKTERY BRANCHES. 

Plan  of  the  relations  of  the  Femoral  Artery. 

Front. 
Fascia  lata, 
Saphenous  nerves, 
Sartorius, 
Arch  of  the  tendinous  canal. 


Inner  Side, 

Femoral  vein, 
Pectineus, 
Adductor  longus, 
Sartorius. 


Femoral  artery. 


Outer  Side. 
Psoas, 
Rectus, 
Vastus  internus. 


Behind. 
Psoas  muscle, 
Femoral  vein, 
Adductor  longus. 

Branches. — The  branches  of  the  Femoral  Artery  are  the — 

Superficial  circumflexa  ilii, 
Superficial  epigastric, 
Superficial  external  pudic, 
Deep  external  pudic, 

S  External  circumflex, 
Internal  circumflex, 
Three  perforating. 
Muscular, 
Anastomotica  magna. 

The  Superficial  circumjlexa  ilii  artery  arises  from  the  femoral, 
immediately  below  Poupart's  ligament,  pierces  the  fascia  lata,  and 
passes  obliquely  towards  the  umbilicus  between  the  two  layers  of 
superficial  fascia.  It  distributes  branches  to  the  inguinal  glands  and 
integument,  and  inosculates  with  branches  of  the  deep  epigastric 
and  of  the  internal  mammary  artery. 

The  Superficial  external  pudic  arises  near  to  the  superficial  epi- 
gastric artery  ;  it  pierces  the  fascia  lata,  at  the  saphenous  opening, 
and  passes  transversely  inwards  crossing  the  spermatic  cord,  to  be 
distributed  to  the  integument  of  the  penis  and  scrotum  in  the  male, 
and  to  the  labia  in  the  female. 

The  Deep  external  pudic  arises  from  the  femoral,  a  little  lower 
down  than  the  preceding;  it  crosses  the  femoral  vein  immediately 
below  the  termination  of  the  internal  saphenous  vein,  and  piercing 
the  pubic  portion  of  the  fascia  lata  passes  beneath  that  fascia  to  the 
inner  border  of  the  thigh,  where  it  again  pierces  the  fascia  ;  having 
become  superficial,  it  is  distributed  to  the  integument  of  the  scrotum 
and  perineum. 

The  Profunda  Femohis  arises  from  the  femoral  artery  at  two 
inches  below  Pouparl's  ligament ;  it  passes  downwards  and  back- 
wards, and  a  little  outwards,  behind  the  adductor  longus  muscle, 
pierces  the  adductor  magnus,  and  is  distributed  to  the  flexor  muscles 
on  the  posterior  part  of  the  thigh. 


PROFUNDA  ARTEEr.  341 

Relations. — In  its  course  downwards  it  rests  successively  upon 
the  pectineus,  the  conjoined  tendon  of  the  psoas  and  iliacus,  ad- 
ductor brevis  and  adductor  magnus  muscles.  To  its  outer  side  the 
tendinous  insertion  of  the  vastus  internus  muscle  intervenes  between 
it  and  the  femur  ;  and  in  front  it  is  separated  from  the  femoral  artery, 
above  by  the  profunda  vein  and  femoral  vein  ;  and  below  by  the  ad- 
ductor longus  muscle. 

Plan  of  the  relations  of  the  Profunda  Artery. 

In  Front. 
Profunda  vein, 
Adductor  longus. 


Profunda  Artery. 


Outer  Side, 
Vastus  internus, 
Femur. 


Behind. 

Pectineus, 

Tendons  of  psoas  and  iliacus, 
Adductor  brevis, 
Adductor  magnus. 

Branches. — The  branches  of  the  profunda  artery  are  the  external 
circumflex,  internal  circumflex,  and  three  perforating  arteries. 

The  External  circumjiex  artery  passes  outwards  between  the 
divisions  of  the  crural  nerve,  then  between  the  rectus  and  crureus 
muscle,  and  divides  into  three  branches ;  ascending,  which  inos- 
culates with  the  terminal  branches  of  the  gluteal  artery  ;  descending, 
which  inosculates  with  the  superior  external  articular  artery ;  and 
middle,  which  continues  the  original  course  of  the  artery  around  the 
thigh,  and  anastomoses  with  branches  of  the  ischiatic,  internal  cir- 
cumflex, and  superior  perforating  artery.  It  supplies  the  muscles 
on  the  anterior  and  outer  side  of  the  thigh. 

The  Internal  circumjiex  artery  is  larger  than  the  external ;  it 
winds  around  the  inner  side  of  the  neck  of  the  femur,  passing  be- 
tween the  pectineus  and  psoas,  and  along  the  border  of  the  external 
obturator  muscle,  to  the  space  between  the  quadratus  femoris  and 
upper  border  of  the  adductor  magnus,  where  it  anastomoses  with 
the  ischiatic,  external  circumflex,  and  superior  perforating  artery. 
It  supplies  the  muscles  on  the  upper  and  inner  side  of  the  thigh, 
anastomosing  with  the  obturator  artery,  and  sends  a  small  branch 
through  the  notch  in  the  acetabulum  into  the  hip-joint. 

The  Superior  perforatiiig  artery  passes  backwards  between  the 
pectineus  and  adductor  brevis,  pierces  the  adductor  magnus  near  to 
the  femur,  and  is  distributed  to  the  posterior  muscles  of  the  thigh  ; 
inosculating  freely  with  the  circumflex  and  ischiatic  artery,  and 
with  the  branches  of  the  middle  perforating  artery. 

The  Middle  perforating  ariery  pierces  the  tendons  of  the  adductor 
brevis  and  magnus,  and  is  distributed  like  the  superior;  inosculating 

29* 


342  POPLITEAL  ABTEEY. 

with  the  superior  and  inferior  perforantes.  This  branch  frequently 
gives  off  the  nutritious  artery  of  the  femur. 

The  Inferior  'perforating  artery  is  given  off  below  the  adductor 
brevis,  and  pierces  the  tendon  of  the  adductor  magnus,  supplying  it 
and  the  flexor  muscles,  and  inosculating  with  the  middle  perforating 
artery  above,  and  with  the  articular  branches  of  the  popliteal  below. 
It  is  through  the  medium  of  these  branches  that  the  collateral  cir- 
culation is  maintained  in  the  limb  after  ligature  of  the  femoral 
artery. 

The  Muscular  branches  are  given  off  by  the  femoral  artery 
throughout  the  whole  of  its  course.  They  supply  the  muscles  in 
immediate  proximity  with  the  artery,  particularly  those  of  the  ante- 
rior aspect  of  the  thigh.  One  of  these  branches,  larger  than  the  rest, 
arises  from  the  femoral  immediately  below  the  origin  of  the  pro- 
funda, and  passing  outwards  between  the  rectus  and  sartorius 
divides  into  branches  which  are  distributed  to  all  the  muscles  of 
the  anterior  aspect  of  the  thigh.  It  may  be  named  the  superior 
muscular  artery. 

The  Anastomotica  magna  arises  from  the  femoral  while  in  the 
tendinous  canal  formed  by  the  adductors  and  vastus  internus.  It 
runs  along  the  tendon  of  the  adductor  magnus  to  the  inner  condyle, 
and  inosculates  with  the  superior  internal  articular  artery;  some  of 
its  branches  are  distributed  to  the  vastus  internus  muscle  and  to  the 
crureus,  and  terminate  by  anastomosing  with  the  branches  of  the 
external  circumflex  and  superior  external  articular  artery. 


POPLITEAL     ARTERY. 

The  popliteal  artery  commences  from  the  termination  of  the 
femoral  at  the  opening  in  the  adductor  magnus  muscle,  and  passes 
obhquely  outwards  through  the  middle  of  the  popliteal  space  to  the 
lov/er  border  of  the  popliteus  muscle,  where  it  divides  into  the  ante- 
rior and  posterior  tibial  artery. 

Relations. — In  its  course  downwards  it  rests  first  on  the  femur, 
then  on  the  posterior  ligament  of  the  knee-joint,  then  on  the  fascia, 
covering  the  popliteus  muscle.  Supfirf daily  it  is  in  relation  with  the 
semimembranosus  muscle,  next  with  a  quantity  of  fat  which  sepa- 
rates it  from  the  deep  fascia,  and  near  its  termination  with  the  gas- 
trocnemius, plantaris,  and  soleus ;  superficial  and  external  to  it  is 
the  popliteal  vein,  and  still  more  superficial  and  external,  the  popli- 
teal nerve.  By  its  inner  side  it  is  in  relation  with  the  semimem- 
branosus, internal  condyle  of  the  femur,  and  inner  head  of  the 
gastrocnemius ;  and  by  its  outer  side  with  the  biceps,  external 
condyle  of  the  femur,  the  outer  head  of  the  gastrocnemius,  the 
plantaris  and  the  soleus. 


ANTERIOR  TIBIAL  ARTERY. 


343 


Plan  of  the  relations  of  the  Popliteal  Artery. 


Inner  Side. 
Semimembranosus, 
Internal  condyle, 
Gastrocnemius. 


Superficially. 
Semimembranosus, 
Popliteal  nerve, 
Popliteal  vein. 
Gastrocnemius, 
Plantaris, 
Soleus. 


Popliteal  Artery. 


Outer  Side, 
Biceps, 

External  condyle. 
Gastrocnemius, 

Plantaris, 

Soleus. 


Deeply. 

Femur,  ,, 

Ligamentum  posticum  Winslowii, 
Popliteal  fascia. 

Branches. — The  branches  of  the  popliteal  artery  are  the — 

Superior  external  articular, 
Superior  internal  articular, 
Azygos  articular, 
Inferior  external  articular, 
Inferior  internal  articular, 
Sural. 

The  Superior  articular  arteries,  external  and  internal,  wind 
around  the  femur  immediately  above  the  condyles,  to  the  front  of 
the  knee-joint,  anastomosing  with  each  other,  with  the  external  cir- 
cumflex, the  anastomotica  magna,  the  inferior  articular,  and  the 
recurrent  of  the  anterior  tibial.  The  external  passes  beneath  the 
tendon  of  the  biceps,  and  the  internal  through  an  arched  opening 
beneath  the  tendon  of  the  abductor  magnus.  They  supply  the  knee- 
joint  and  the  lower  part  of  the  femur. 

The  Azygos  articular  artery  pierces  the  posterior  ligament  of  the 
joint,  the  ligamentum  posticum  Winslowii,  and  supplies  the  synovial 
membrane  in  its  interior.  There  are  frequently  several  posterior 
articular  arteries. 

The  Inferior  articular  arteries  wind  around  the  head  of  the  tibia 
immediately  below  the  joint,  and  anastomose  with  each  other,  the 
superior  articular  arteries,  and  the  recurrent  of  the  anterior  tibial. 
The  external  passes  beneath  the  two  external  lateral  ligaments  of 
the  joint,  and  the  internal  beneath  the  internal  lateral  ligament. 
They  supply  the  knee-joint  and  the  heads  of  the  tibia  and  fibula. 

The  Sural  arteries  (sura,  the  calf)  are  two  large  muscular 
branches,  which  are  distributed  to  the  two  heads  of  the  gastrocne- 
mius muscle. 


ANTERIOR     TIBIAL     ARTERY. 


The  anterior  tibial  artery  passes  forwards  between  the  two  heads 
of  the  tibialis  posticus  muscle,  and  through  the  opening  in  the  upper 


344  ANTERIOR  TIBIAL  ARTERY. 

part  of  the  interosseous  membrane,  to  the  anterior  tibial  region.  It 
then  runs  down  the  anterior  aspect  of  the  leg  to  the  ankle-joint, 
where  it  becomes  the  dorsalis  pedis. 

Relations. — In  its  course  downwards  it  rests  upon  the  interosseous 
membrane  (to  which  it  is  connected  by  a  little  tendinous  arch  which 
is  thrown  across  it),  the  lower  part  of  the  tibia,  and  the  anterior 
ligament  of  the  joint.  In  the  upper  third  of  its  course  it  is  situated 
between  the  tibialis  anticus  and  extensor  longus  digitorum ;  lower 
down  between  the  tibialis  anticus  and  extensor  proprius  poUicis  ;  and 
just  before  it  reaches  the  ankle  it  is  crossed  by  the  tendon  of  the 
extensor  proprius  pollicis,  and  becomes  placed  between  that  tendon 
and  the  tendons  of  the  extensor  longus  digitorum.  Its  immediate 
relations  are  the  venae  comites  and  the  anterior  tibial  nerve,  which 
lies  at  first  to  its  outer  side,  and  at  about  the  middle  of  the  leg  be- 
comes placed  superficially  to  the  artery. 

Plan  of  the  relations  of  the  Anterior  Tibial  Artery. 

Front. 
Deep  fascia, 
Tibialis  anticus. 
Extensor  longus  digitorum, 
Extensor  proprius  pollicis, 
Anterior  tibial  nerve. 


Inner  Side. 
Tibialis  anticus, 
Tendon   of   the 
extensor   pro- 
prius pollicis. 


Anterior  Tibial 

Artery. 


Outer  Side. 
Anterior  tibial  nerve, 
Extensor  longus  digitorum, 
Extensor  proprius  pollicis, 
Tendons  of  the  extensor 
longus  digitorum. 


Behind. 
Interosseous  membrane. 
Tibia  (lowrer  fourth), 
Ankle  joint. 

Branches. — The  branches  of  the  Anterior  Tibial  Artery  are  the — 

Recurrent, 
Muscular, 
External  malleolar, 
Internal  malleolar. 

The  Recurrent  branch  passes  upwards  beneath  the  origin  of  the 
tibialis  anticus  muscle  to  the  front  of  the  knee-joint,  upon  which  it 
is  distributed,  anastomosing  with  the  articular  arteries. 

The  Muscular  branches  are  very  numerous,  they  supply  the  mus- 
cles of  the  anterior  tibial  region. 

The  Malleolar  arteries  are  distributed  to  the  ankle-joint ;  the  ex- 
ternal, passing  beneath  the  tendons  of  the  extensor  longus  digitorum 
and  peroneus  tertius,  inosculates  with  the  anterior  peroneal  artery 
and  with  the  branches  of  the  dorsalis  y^edis;  the  internal,  beneath 
the  tendons  of  the  extensor  proprius  pollicis  and  tibialis  anticus,  in- 
osculates with  branches  of  the  posterior  tibial  and  of  the  internal 
plantar  artery.     They  supply  branches  to  the  ankle-joint. 


DORSAL  ARTERIES  OF  THE  FOOT. 


345 


The  DoRSALis  Pedis  Artery  is  continued  forwards  along  the 
tibial  side  of  the  dorsum  of  the  foot,  from  the  ankle  to  the  base  of 
the  metatarsal  bone  of  the  great  toe,  where  it  divides  into  two 
branches,  the  dorsalis  hallucis  and  communicating. 

Relations. — The  dorsalis  pedis  is  situated  along  the  outer  border 
of  the  tendon  of  the  extensor  proprius  pollicis  ;  on  its  fibular  side  is 
the  innermost  tendon  of  the  extensor  longus  digitorum,  and  near  to 
its  termination  it  is  crossed  by  the  inner  tendon  of  the  extensor  brevis 
digitorum.  It  is  accompanied  by  venae  comites,  and  has  the  con- 
tinuation of  the  anterior  tibial  nerve  to  its  outer  side. 

Plan  of  the  relations  of  the  Dorsalis  Pedis  Artery. 

In  Front. 

Integument, 
Deep  fascia, 

Inner  tendon  of  the  extensor 
brevis  digitorum. 


Inner  Side. 
Tendon  of  the  ex- 
tensor proprius 
pollicis. 


Dorsalis  Pedis 
Artery. 


Outer  Side, 
Tendon   of  the   extensor 

longus  digitorum, 
Border   of  the   extensor 

brevis  digitorum  muscle. 


Behind. 

Bones  of  the  tarsus,  with 
their  ligaments. 

Branches. — The  branches  of  this  artery  are  the — 

Tarsea, 

Metatarsea, — interossese, 

Dorsalis  hallucis, — collateral  digital, 

Communicating. 

The  Tarsea  arches  transversely  across  the  tarsus,  beneath  the 
extensor  brevis  digitorum  muscle,  and  supplies  the  articulations  of 
the  tarsal  bones  and  the  outer  side  of  the  foot;  it  anastomoses  with 
the  external  malleolar,  the  peroneal  arteries,  and  with  the  external 
plantar. 

The  Metatarsea  forms  an  arch  across  the  base  of  the  metatarsal 
bones,  and  supplies  the  outer  side  of  the  foot,  anastomosing  with  the 
tarsea  and  with  the  external  plantar  artery.  The  metatarsea  giyes 
off  three  branches,  the  interossea;,  which  pass  forwards  upon  the 
dorsal  interossei  muscles,  and  divide  into  two  collateral  branches 
for  the  adjoining  toes.  At  their  commencement  these  interosseous 
branches  receive  the  posterior  perforating  arteries  from  the  plantar 
arch,  and  opposite  the  heads  of  the  metatarsal  bones  they  are  joined 
by  the  anterior  perforating  branches  from  the  digital  arteries. 

The  Dorsalis  hallucis  runs  forward  upon  the  first  dorsal  interos- 
seous muscle,  and  at  the  base  of  the  first  phalanx  divides  into  two 
branches,  one  of  which  passes  inwards  beneath  the  tendon  of  the 
^extensor  proprius  pollicis,  and  is  distributed  to  the  inner  border  of 


346 


ANTERIOR  AND  POSTERIOR  TIBIALIS. 
Fig.  131.  Fig.  132. 


Fig.  131.  The  anterior  aspect  of  the  leg  and  foot,  showing  the  anterior  tibial  and 
dorsalis  pedis  arteries,  with  their  branches.  1.  The  tendon  of  insertion  of  the  quad- 
riceps  extensor  muscle.  2.  The  insertion  of  the  ligamentum  patella?  into  the  lower 
border  of  the  patella.  3.  The  tibia,  4.  The  extensor  proprius  pollicis  muscle.  5. 
The  extensor  longus  digitorum.  6.  The  peronei  muscles.  7.  The  inner  belly  of 
the  gastrocnemius  and  the  soleus.  8.  The  annular  ligament  beneath  which  the  extensor 
tendons  and  the  anterior  tibial  artery  pass  into  the  dorsum  of  the  foot.  9.  The  ante- 
rior tibial  artery.  10.  Its  recurrent  branch  inosculating  with  (2)  the  inferior  articular, 
and  (1)  the  superior  articular  artery,  branches  of  the  popliteal.  11.  The  internal  mal- 
leolar artery.  17.  The  external  malleolar  inosculating  with  the  anterior  peroneal 
artery  12,  13.  The  dorsalis  pedis  artery.  14.  The  tarsea  and  metatarsea  arteries; 
the  tursea  is  nearest  the  ankle,  the  metatarsea  is  seen  giving  off  the  interosseaj.  15. 
The  dorsalis  hallucis  artery.     16.  The  communicating  branch. 

Fig.  132.  A  posterior  view  of  the  leg,  showing  the  popliteal  and.  posterior  tibial 
artery.  1.  The  tendons  forming  the  inner  hamstring.  2.  The  tendon  of  the  biceps 
forming  the  outer  hamstring.  3.  The  poplitcus  muscle.  4.  The  flexor  longus  digitorum. 
5.  The  tibialis  posticus.  6.  The  fibula ;  immediately  below  the  figure  is  the  origin  of 
the  flexor  longus  pollicis;  the  muscle  has  been  removed  in  order  to  expose  the  peroneal 
artery.  7.  The  peronei  muscles,  longus  and  brevis.  8.  The  lower  part  of  the  flexor 
longus  pollicis  muscle  with  its  tendon.  9.  The  popliteal  artery  giving  off  its  articular 
and  musculai-  branches;  the  two  superior  articular  arc  seen  in  the  upper  part  of  the 
popliteal  space  passing  above  the  two  heads  of  the  gastrocnemius  muscle,  which  ar/B 
cut  through  near  to  their  origin.  The  two  inferior  arc  in  relation  with  the  popliteus 
muscle.  10.  The  anterior  tibial  artery  passing  through  the  angular  interspace  between 
the  two  heads  of  the  tibialis  posticus  muscle.  11.  The  posterior  tibial  artery.  12.  The 
relative  position  of  the  tendons  and  artery  at  the  inner  ankle  from  within  outwards, 
previously  to  their  passing  beneath  the  internal  annular  ligament.  13.  The  peroneal 
artery,  dividing  into  two  branches  ;  the  anterior  peroneal  is  seen  piercing  the  interos- 
seous membrane.     14.  The  posterior  peroneal. 


POSTERIOR  TIBIAL  ARTERY.  347 

the  great  toe,  "while  the  other  bifurcates  for  the  supply  of  the  adja- 
cent sides  of  the  great  and  second  toes. 

The  Communicating  artery  passes  into  the  sole  of  the  foot  between 
the  two  heads  of  the  first  dorsal  interosseous  muscle,  and  inosculates 
with  the  termination  of  the  external  plantar  artery. 

Besides  the  preceding,  numerous  branches  are  distributed  to  the 
bones  and  articulations  of  the  foot,  particularly  along  the  inner 
border  of  the  latter. 

POSTERIOR     TIBIAL     ARTERY. 

The  posterior  tibial  artery  passes  obliquely  downwards  along  the 
tibial  side  of  the  leg  from  the  lower  border  of  the  popliteus  muscle 
to  the  concavity  of  the  os  calcis,  where  it  divides  into  the  internal 
and  external  plantar  artery. 

Relations. — In  its  course  downwards  it  lies  upon  the  tibialis  pos- 
ticus, next  upon  the  flexor  longus  digitorum,  and  then  upon  the 
tibia;  it  is  covered  in  by  the  intermuscular  fascia  which  separates 
it  above  from  the  soleus,  and  below  from  the  deep  fascia  of  the  leg 
and  the  integument.  It  is  accompanied  by  its  ven^e  comites,  and 
by  the  posterior  tibial  nerve,  which  lies  at  first  to  its  outer  side,  then 
superficially  to  it,  and  again  to  its  outer  side. 

Plan  of  the  relations  of  the  Posterior  Tibial  Artery. 

Superficially. 
Soleus, 
Deep  fascia, 
The  intermuscular  fascia. 


Inner  Side. 
Vein. 


Posterior  Tibial 

Artery. 


Outer  Side. 
Posterior  tibial  nerve. 
Vein. 


Deeply. 
Tibialis  posticus, 
Flexor  longus  digitorum, 
Tibia. 

Branches. — The  branches  of  the  posterior  tibial  artery  are  the — 

Peroneal, 
Nutritious, 
Muscular, 
Internal  calcanean, 
Internal  plantar, 
External  plantar. 

The  Peroneal  artery  is  given  oflf  from  the  posterior  tibial  at  about 
two  inches  below  the  lower  border  of  the  popliteus  muscle ;  it  is 
nearly  as  large  as  the  anterior  tibial  artery,  and  passes  obliquely  out- 
wards to  the  fibula.  It  then  runs  downwards  along  the  inner  border 
of  the  fibula  to  its  lower  third,  where  it  divides  into  the  anterior  and 
posterior  peroneal  artery. 

Relations. — The  peroneal  artery  rests  upon  the  tibialis  posticus 


348  PLANTAR  ARTERIES. 

muscle,  and  is  covered  in  by  the  soleus,  the  intermuscular  fascia 
and  the  flexor  longus  poUicis,  having  the  fibula  to  its  outer  side. 

Plan  of  the  relations  of  the  Peroneal  Artery. 

In  Front. 

Soleus, 

Intermuscular  fascia, 
Flexor  longus  pollicis. 


Peroneal  Artery.  ^"'^''  ^*'''«- 

Fibula. 


Behind, 
Tibialis  posticus. 

Branches. — The  branches  of  the  peroneal  artery  are  muscular  to 
the  neighbouring  muscles,  particularly  to  the  soleus,  and  the  two 
terminal  branches  anterior  and  posterior  peroneal. 

The  Anterior  peroneal  pierces  the  interosseous  membrane  at  the 
lower  third  of  the  leg,  and  is  distributed  on  the  front  of  the  outer 
malleolus,  anastomosing  with  the  external  malleolar  and  tarsal 
artery.  ,.  This  branch  is  very  variable  in  size. 

The  Posterior  peroneal  continues  onwards  along  the  posterior 
aspect  of  the  outer  malleolus  to  the  side  of  the  os  calcis,  to  which 
and  to  the  muscles  arising  from  it,  it  distributes  external  calcanean 
branches.  It  anastomoses  with  the  anterior  peroneal,  tarsal,  ex- 
ternal plantar,  and  posterior  tibial  artery. 

The  Nutritious  artery  of  the  tibia  arises  from  the  trunk  of  the 
tibial,  frequently  above  the  origin  of  the  peroneal,  and  proceeds 
to  the  nutritious  canal,  which  it  traverses  obliquely  from  below 
upwards. 

The  Muscular  branches  of  the  posterior  tibial  artery  are  distri- 
buted to  the  soleus  and  to  the  deep  muscles  on  the  posterior  aspect 
of  the  leg.  One  of  these  branches  is  deserving  of  notice,  a  reciirrent 
branch,  which  arises  from  the  posterior  tibial  above  the  origin  of 
the  peroneal  artery,  pierces  the  soleus,  and  is  distributed  upon  the 
inner  side  of  the  tibia,  anastomosing  with  the  inferior  internal 
articular. 

The  Internal  calcanean  branches,  three  or  four  in  number,  pro- 
ceed from  the  posterior  tibial  artery  immediately  before  its  division  ; 
they  are  distributed  to  the  inner  side  of  the  os  calcis,  to  the  integu- 
ment, and  to  the  muscles  which  arise  from  its  inner  tuberosity,  and 
they  anastomose  with  the  external  calcanean  branches,  and  with 
all  the  neighbouring  arteries. 

PLANTAR     ARTERIES. 

The  Internal  -plantar  artery  proceeds  from  the  bifurcation  of  the 
posterior  tibial  at  the  inner  malleolus,  and  passes  along  the  inner 
border  of  the  foot  between  the  abductor  pollicis  and  flexor  brevis 
digitorum  muscles,  supplying  the  inner  border  of  the  foot  and 
great  toe. 


PLANTAR  ARTERIES. 


349 


The  External  plantar  artery,  much  larger  than  the  internal, 
passes  obliquely  outwards  between  the  first  and  second  layers  of  the 
plantar  muscles,  to  the  fifth  metatarsal  space.  It  then  turns  hori- 
zontally inwards  between  the  second  and  third  layers,  to  the  first 
metatarsal  space,  where  it  inosculates  with  the  communicating 
branch  from  the  dorsalis  pedis.  The  horizontal 
portion  of  the  artery  describes  a  slight  curve,  ^^s-  ^33. 

having   the   convexity  forwards ;    this   is    the 
plantar  arch. 

Branches. — The  branches  of  the  external 
plantar  artery  are  the — 

Muscular, 

Articular, 

Digital, — anterior  perforating, 

Posterior  perforating. 

The  Muscular  brandies  are  distributed  to  the 
muscles  in  the  sole  of  the  foot. 

The  Articular  branches  supply  the  ligaments 
of  the  articulations  of  the  tarsus,  and  their 
synovial  membranes. 

The  Digital  branches  are  four  in  number  : — 
the  first  is  distributed  to  the  outer  side  of  the 
little  toe;  the  three  others  pass  forwards  to  the 
cleft  between  the  toes,  and  divide  into  collateral 
branches,  which  supply  the  adjacent  sides  of 
the  three  external  toes,  and  the  outer  side  of 
the  second.  At  the  bifurcation  of  the  toes,  a  small  branch  is  sent 
upwards  from  each  digital  artery,  to  inosculate  with  the  interos- 
seous branches  of  the  metatarsea ;  these  are  the  anterior  perforating 
arteries. 

The  Posterior  perforating  are  three  small  branches  which  pass 
upwards  between  the  heads  of  the  three  external  dorsal  interossei 
muscles,  to  inosculate  with  the  arch  formed  by  the  metatarsea 
artery. 

Varieties  in  the  Arteries  of  the  lovoer  extremity. — The  femoral 
artery  occasionally  divides  at  Poupart's  ligament  into  two  branches, 
and  sometimes  into  three ;  the  former  is  an  instance  of  the  high 
division  of  the  profunda  artery ;  and  in  a  case  of  the  latter  kind 
which  occurred  during  my  dissections,  the  branches  were  the  pro- 
funda, the  superficial  femoral,  and  internal  circumflex  artery.  Dr. 
Quain  in  his  "  Elements  of  Anatomy,"  records  an  instance  of  a  high 


Fi^.  133,  The  arteries  of  the  sole  of  the  foot;  the  first  and  a  part  of  the  second 
layer  of  muscles  having  been  removed.  1.  The  under  and  posterior  part  of  the  os 
calcis  ;  to  which  the  origins  of  the  first  layer  of  muscles  remain  attached.  2.  The 
musculus  accessorius.  3.  The  long-  flexor  tendons.  4.  The  tendon  of  tlie  peronens 
longus.  5.  The  termination  of  the  posterior  tibial  artery.  6.  The  internal  plantar.  7. 
The  external  plantar  artery.  8.  The  plantar  arch  giving  off  four  digital  branches, 
which  pass  forwards  on  the  interossei  muscles  to  divide  into  collateral  branches. 

30 


350  PULMONARY  ARTERY. 

division  of  the  femoral  artervj  in  which  the  two  vessels  became 
again  united  in  the  popliteal  region.  The  point  of  origin  of  the  pro- 
funda artery  varies  considerably  in  different  subjects,  being  some- 
times nearer  to  and  sometimes  farther  from  Poupart's  ligament,  but 
more  frequently  the  former.  The  branches  of  the  popliteal  artery 
are  very  liable  to  variety  in  size ;  and  in  all  these  cases  the  com- 
pensating principle,  so  constant  in  the  vascular  system,  is  strikingly 
manifested.  When  the  anterior  tibial  is  of  small  size,  the  peroneal 
is  large ;  and,  in  place  of  dividing  into  two  terminal  branches  at 
the  lower  third  of  the  leg,  descends  to  the  lower  part  of  the  inter- 
osseous membrane,  and  emerges  upon  the  front  of  the  ankle,  to  sup- 
ply the  dorsum  of  the  foot ;  or  the  posterior  tibial  and  plantar  arteries 
are  large,  and  the  external  plantar  is  continued  between  the  heads 
of  the  first  dorsal  interosseous  muscle,  to  be  distributed  to  the  dorsal 
surface  of  the  foot.  Sometimes  the  posterior  tibial  artery  is  small 
and  threadlike;  and  the  peroneal,  after  descending  to  the  ankle, 
curves  inwards  to  the  inner  malleolus,  and  divides  into  the  two 
plantar  arteries.  If  in  this  case  the  posterior  tibial  be  sufficiently 
large  to  reach  the  ankle,  it  inosculates  with  the  peroneal  previously 
to  its  division.  The  internal  plantar  artery  sometimes  takes  the  dis- 
tribution of  the  external  plantar,  which  is  short  and  diminutive,  and 
the  latter  not  unfrequently  replaces  a  deficient  dorsalis  pedis. 

The  varieties  of  arteries  are  interesting  in  the  practical  applica- 
tion of  a  knowledge  of  their  principal  forms  to  surgical  operations ; 
in  their  transcendental  anatomy,  as  illustrating  the  normal  distribu- 
tion in  animals;  or  in  many  cases,  as  diverticula  permitted  by  Na- 
ture, to  teach  her  observers  two  important  principles: — -first,  in 
respect  to  herself,  that,  however,  in  her  means  she  may  indulge  in 
change,  the  end  is  never  overlooked,  and  a  limb  is  as  surely  supplied 
by  a  leash  of  arteries,  various  in  their  course,  as  by  those  which 
we  are  pleased  to  consider  normal  in  distribution  ;  and  secondly, 
with  regard  to  us ;  that  we  should  ever  be  keenly  alive  to  what  is 
passing  beneath  our  observation,  and  ever  ready  in  the  most  serious 
operation  to  deviate  from  our  course  and  avoid, — or  give  eyes  to 
our  knife,  that  it  may  see — the  concealed  dangers  which  it  is  our 
pride  to  be  able  to  contend  with  and  vanquish. 

PULMONARY     ARTERY. 

The  pulmonary  artery  arises  from  the  left  side  of  the  base  of  the 
right  ventricle  in  front  of  the  origin  of  the  aorta,  and  ascends 
obliquely  to  the  under  surface  of  the  arch  of  the  aorta,  where  it 
divides  into  the  right  and  left  pulmonary  arteries.  In  its  course 
upwards  and  backwards  it  inclines  to  the  left  side,  crossing  the 
commencement  of  the  aorta,  and  is  connected  to  the  under  surface 
of  the  arch  by  a  ligamentous  cord,  the  remains  of  the  ductus  arte- 
riosus. 

Relations. — It  is  enclosed  for  one  half  of  its  extent  by  the  pericar- 
dium, and  receives  the  attachment  of  the  fibrous  portion  of  the  peri- 


PULMONARY  AKTERY.  351 

cardium  by  its  upper  portion.  Behind,  it  rests  against  the  ascending 
aorta  ;  on  either  side  is  the  appendix  of  the  corresponding  auricle 
and  a  coronary  artery  ;  and  above,  the  cardiac  ganglion  and  the 
remains  of  the  ductus  arteriosus. 

The  Right  pulmovary  artery  passes  beneath  the  arch  and  behind 
the  ascending  aorta,  and  in  the  root  of  the  lungs  divides  into  three 
branches  for  the  three  lobes. 

The  Left  pulmonary  artery,  rather  larger  than  the  right,  passes  in 
front  of  the  descending  aorta,  to  the  root  of  the  left  lung,  to  which  it 
is  distributed.  These  arteries  divide  and  subdivide  in  the  structure 
of  the  lungs,  and  terminate  in  capillary  vessels  which  form  a  net- 
work around  the  bronchial  cells,  and  become  continuous  with  the 
radicles  of  the  pulmonary  veins. 

Relations. — In  the  root  of  the  right  lung,  examined  from  above 
downwards,  the  pulmonary  artery  is  situated  between  the  bronchus, 
and  pulmonary  veins ;  the  former  being  above,  the  latter  below ; 
while  in  the  left  lung  the  artery  is  the  highest,  next  the  bronchus, 
and  then  the  veins.  On  both  sides,  from  before  backwards,  the 
artery  is  situated  between  the  veins  and  bronchi,  the  former  being 
in  front,  and  the  latter  behind. 


CHAPTER    VI. 

ON  THE  VEINS. 

Thk  veins  are  the  vessels  which  return  the  blood  to  the  auricles 
of  the  heart,  after  it  has  been  circulated  by  the  arteries  through  the 
various  tissues  of  the  body.  They  are  much  thinner  in  structure 
than  the  arteries,  so  that  when  emptied  of  their  blood  they  become 
flattened  and  collapsed.  The  veins  of  the  systemic  circulation 
convey  the  dark-coloured  and  impure  or  venous  blood  from  the 
capillary  system  to  the  right  auricle  of  the  heart,  and  they  are 
found  after  death  to  be  more  or  less  distended  with  that  fluid.  The 
veins  of  the  pulmonary  circulation  resemble  the  arteries  of  the 
systemic  circulation  in  containing  during  life  the  pure  or  arterial 
blood,  which  they  transmit  from  the  capillaries  of  the  lungs  to  the 
left  auricle. 

The  veins  commence  by  minute  radicles  in  the  capillaries  which 
are  every  where  distributed  through  the  textures  of  the  body,  and 
converge  to  constitute  larger  and  larger  branches,  till  they  termi- 
nate in  the  large  trunks  which  convey  the  venous  blood  directly  to 
the  heart.  In  diameter  they  are  much  larger  than  the  arteries,  and 
like  those  vessels  their  combined  areas  would  constitute  an  imagi- 
nary cone,  whereof  the  apex  is  placed  at  the  heart,  and  the  base  at 
the  sur'ace  of  the  body.  It  follows  from  this  arrangement,  that  the 
blood  in  returning  to  the  heart  is  passing  from  a  larger  into  a  smaller 
channel,  and  therefore  increases  in  rapidity  during  its  course. 

Veins  admit  of  a  threefold  division,  into  superficial,  deep,  and 
sinuses. 

The  Superficial  veins  return  the  blood  from  the  integument  and 
superficial  structures,  and  take  their  course  between  the  layers  of 
the  superficial  fascia ;  they  then  pierce  the  deep  fascia  in  the  most 
convenient  and  protected  situations,  and  terminate  in  the  deep 
veins.  They  are  unaccompanied  by  arteries,  and  are  the  vessels 
usually  selected  for  venesection. 

The  Deep  veins  are  situated  among  the  deeper  structures  of  the 
body,  and  generally  in  relation  with  the  arteries;  in  the  limbs  they 
are  enclosed  in  the  same  sheath  with  those  vessels,  and  they  return 
the  venous  blood  from  the  capillaries  of  the  deep  tissues.  In  com- 
pany with  all  the  smaller,  and  also  with  the  secondary  arteries,  as 
the  brachial,  radial,  and  ulnar  in  the  upper,  and  the  tibial  and  pero- 
neal in  the  lower  extremity,  there  are  two  veins,  placed  one  on  each 
side  of  the  artery,  and  naaied  venoi  cornites.  The  larger  arteries,  as 
the  axillary,  subclavian,  carotid,  popliteal,  femoral,  &c.,  are  accom- 


STRUCTURE  OF  VEINS.  353 

panied  by  a  single  venous  trunk.  Sinuses  differ  from  veins  in  their 
structure,  and  also  in  their  n:iode  of  distribution,  being  confined  to 
especial  organs,  situated  within  their  substance.  The  principal  venous 
sinuses  are  those  of  the  dura  mater,  of  the  diploe,  of  the  cancellous 
structure  of  bone,  and  of  the  uterus. 

The  communications  between  veins  are  even  more  frequent  than 
those  of  arteries,  and  they  take  place  between  the  larger  as  well 
as  among  the  smaller  vessels  ;  the  venae  comites  communicate  with 
each  other  very  frequently  in  their  course,  by  means  of  short  trans- 
verse branches  which  pass  from  one  to  the  other.  These  communi- 
cations are  strikingly  exhibited  in  the  frequent  inosculations  of  the 
spinal  veins,  and  in  the  various  venous  plexuses,  as  the  spermatic 
plexus,  vesical  plexus,  &c.  The  office  of  these  inosculations  is  very 
apparent,  as  tending  to  obviate  the  obstructions  to  which  the  veins 
are  particularly  liable  from  the  thinness  of  their  coats,  and  from 
their  inability  to  overcome  much  impediment  by  the  force  of  their 
current. 

Veins  are  composed  of  three  tunics,  external,  middle,  and  in- 
ternal. 

The  External  or  Cellular  coat  is  dense  and  resisting,  and  resem- 
bles the  cellular  tunic  of  arteries.  The  middle  coat  is  fibrous  like 
that  of  arteries,  but  extremely  thin ;  so  that  its  existence  is  ques- 
tioned by  some  anatomists.  The  internal  coat  is  serous,  and  also 
similar  to  that  of  arteries  ;  it  is  continuous  with  the  lining  membrane 
of  the  heart  at  one  extremity,  and  with  the  lining  of  the  capillaries 
at  the  other.  At  certain  intervals  the  internal  coat  forms  folds  or 
duplicatures,  which  constitute  valves.  The  valves  of  veins  are 
generally  composed  of  two  semilunar  folds,  one  on  each  side  of 
the  cylinder  of  the  vessel,  occasionally  of  a  single  duplicature, 
having  a  spiral  direction,  and  in  rare  instances  of  three.  The  free 
extremity  of  the  valvular  folds  is  concave,  and  directed  forwards, 
so  that  while  the  current  of  blood  would  be  permitted  to  flow  freely 
towards  the  heart,  the  valves  would  become  distended  and  the  current 
intercepted  if  the  stream  became  retrograde  in  its  course.  Upon  the 
cardiac  side  of  each  valve  the  vein  is  expanded  into  two  pouches 
(sinuses),  corresponding  with  the  segments  of  the  valves,  which  give 
to  the  distended  or  injected  vein  a  knotted  appearance.  The  valves 
are  most  numerous  in  the  veins  of  the  extremities,  particularly  in  the 
deeper  veins,  and  they  are  generally  absent  in  the  smaller  veins, 
and  in  the  veins  of  the  viscera,  as  in  the  portal  and  cerebral  veins : 
they  are  also  absent  in  the  large  trunks,  as  in  the  venae  cavas,  venae 
azygos,  innominatae,  and  iliac  veins. 

Sinuses  are  venous  channels,  excavated  in  the  structure  of  an 
organ,  and  lined  by  the  internal  coat  of  the  veins ;  of  this  structure 
are  the  sinuses  of  the  dura  mater,  whose  external  covering  is  the 
fibrous  tissue  of  the  membrane,  and  the  internal,  the  serous  layer  of 
the  veins.  The  external  investment  of  the  sinuses  of  the  uterus  is 
the  tissue  of  that  organ  ;  and  that  of  the  bones,  the  lining  membrane 
of  the  cells  and  canals. 

30* 


354  VEINS  OF  THE  HEAD  AND  NECK. 

Veins,  like  ai'teries,  are  supplied  with  nutritious  vessels,  the  vasa 
vasorum  ;  and  it  is  to  be  presumed  that  nervous  filaments  are  dis- 
tributed to  their  coats. 

I  shall  describe  the  veins  according  to  the  primary  division  of 
the  body ;  taking  first,  those  of  the  head  and  neck ;  next,  those  of 
the  upper  extremity  ;  then  those  of  the  lovver  extremity  ;  and  lastly, 
the  veins  of  the  trunk. 

VEINS     OF     THE     HEAD     AND     NECK. 

The  veins  of  the  head  and  neck  may  be  arranged  into  three 
groups,  viz. :  1.  Veins  of  the  exterior  of  the  head.  2.  Veins  of  the 
diploe  and  interior  of  the  cranium.     3.  Veins  of  the  neck. 

The  veins  of  the  exterior  of  the  head  are  the — 

'  Facial, 

Internal  maxillary, 
Temporal, 
Temporo-maxillary, 
Posterior  auricular, 
Occipital. 

The  Facial  vein  commences  upon  the  anterior  part  of  the  skull 
in  a  venous  plexus,  formed  by  the  communications  of  the  branches 
of  the  temporal,  and  descends  along  the  middle  line  of  the  fore- 
head, under  the  name  oi  frontal  vein,  to  the  root  of  the  nose,  where 
it  is  connected  with  its  fellow  of  the  opposite  side  by  a  communi- 
cating trunk  which  constitutes  the  nasal  arch.  There  are  usually 
two  frontal  veins  which  communicate  by  a  transverse  inosculation  ; 
but  sometimes  the  vein  is  single  and  bifurcates  at  the  root  of  the 
nose,  into  the  two  angular  veins.  From  the  nasal  arch,  the  frontal 
is  continued  downwards  by  the  side  of  the  root  of  the  nose,  under 
the  name  of  the  angular  vein ;  it  then  passes  beneath  the  zygomatic 
muscles  and  becomes  the  facial  vein,  and  descends  along  the  ante- 
rior border  of  the  masseter  muscle,  crossing  the  body  of  the  lower 
jaw,  by  the  side  of  the  facial  artery,  to  the  submaxillary  gland, 
and  from  thence  to  the  internal  jugular  vein,  in  which  it  ter- 
minates. 

The  branches  which  the  facial  vein  receives  in  its  course  are,  the 
supra-orbital,  which  joins  the  frontal  vein  ;  the  dorsal  veins  of  the 
nose  which  terminate  in  the  nasal  arch  ;  the  ophthalmic,  which  com- 
municates with  the  angular  vein;  the  palpebral  and  nasal,  which 
also  open  into  the  angular  vein ;  a  considerable  trunk,  the  alveolar, 
which  returns  the  blood  from  the  spheno-maxillary  fossa,  from  the 
infra-orbital,  palatine,  vidian  and  spheno-palatine,  and  joins  the 
facial  beneath  the  zygomatic  process  of  the  superior  maxillary 
bone,  and  the  veins  corresponding  with  the  branches  of  the  facial 
artery. 

The  Internal  maxillary  vein  receives  the  branches  from  the 
zygomatic  and  pterygoid  fossae;  these  are  so  numerous  and  com- 
municate so  freely  as  to  constitute  a  pterygoid  plexus.     Passing 


VEINS  OF  THE  DIPLOE.  355 

backwards  behind  the  neck  of  the  lower  jaw,  the  internal  maxillary- 
joins  Vith  the  temporal  vein,  and  the  common  trunk  resulting  from 
this  union  constitutes  the  temporo-maxiUary  vein. 

The  Temporal  vein  commences  on  the  vertex  of  the  head  by  a 
plexiform  network  which  is  continuous  with  the  frontal,  the  tem- 
poral, auricular,  and  occipital  veins.  The  ramifications  of  this 
plexus  form  an  anterior  and  a  posterior  branch  which  unite  imme- 
diately above  the  zygoma;  the  trunk  is  here  joined  by  another  large 
vein,  the  middle  temporal,  which  collects  the  blood  from  the  temporal 
muscle,  and  around  the  outer  segment  of  the  orbit,  and  pierces  the 
temporal  fascia  near  the  root  of  the  zygoma.  The  temporal  vein 
then  descends  between  the  meatus  auditorius  externus  and  the  con- 
dyle of  the  lower  jaw,  and  unites  with  the  internal  maxillary  vein 
to  form  the  temporo-maxillary. 

The  Temporo-maxillary  vein,  formed  by  the  union  of  the  temporal 
and  internal  maxillary,  passes  downwards  in  the  substance  of  the 
parotid  gland  to  its  lower  border,  where  it  becomes  the  external 
jugular  vein.  It  receives  in  its  course  the  anterior  auricular,  masse- 
teric, transverse  facial  and  parotid  veins,  and  near  its  termination 
is  joined  by  the  posterior  auricular  vein. 

The  Posterior  auricular  vein  communicates  with  the  plexus  upon 
the  vertex  of  the  head,  and  descends  behind  the  ear  to  the  temporo- 
maxillary  vein,  immediately  before  that  vessel  merges  in  the  external 
jugular.  It  receives  in  its  course  the  veins  from  the  external  ear 
and  the  stylo-mastoid  vein. 

The  Occipital  vein,  commencing  posteriorly  in  the  plexus  of  the 
vertex  of  the  head,  follows  the  direction  of  the  occipital  artery,  and 
passing  deeply  beneath  the  muscles  of  the  back  part  of  the  neck, 
terminates  in  the  external  jugular  vein.  This  vein  communicates 
with  the  lateral  sinus  by  means  of  a  large  branch  which  passes 
through  the  mastoid  foramen,  the  mastoid  vein. 

VEINS     OF     THE     DIPLOE. 

The  diploe  of  the  bones  of  the  head  is  furnished  in  the  adult  with 
irregular  sinuses,  which  are  formed  by  a  continuation  of  the  serous 
membrane  of  the  veins  into  the  osseous  canals  in  which  they  are 
lodged.  At  the  middle  period  of  life  these  sinuses  are  confined  to 
the  particular  bones ;  but  in  old  age,  after  the  ossification  of  the 
sutures,  they  may  be  traced  from  one  bone  to  the  next.  They  receive 
their  blood  from  the  capillaries  supplying  the  cellular  structure  of 
the  diploe,  and  terminate  externally  in  the  veins  of  the  pericranium, 
and  internally  in  the  veins  and  sinuses  of  the  dura  mater.  These 
veins  are  separated  from  the  bony  walls  of  the  canals  by  a  thin 
layer  of  marrow. 

CEREBRAL  AND  CEREBELLAR  VEINS. 

The  cerebral  veins  are  remarkable  for  the  absence  of  valves,  and 
for  the  extreme  tenuity  of  their  coats.  They  may  be  divided  into 
the  superficial,  and  deep  or  ventricular  veins. 


356  SINUSES  OF  THE  DURA  MATER. 

The  SvperficiaJ  cerebral  vsiyis  are  situated  upon  the  surface  of  the 
hemispheres,  lying  in  the  grooves  formed  by  the  convexities  Cf  the 
convolutions.  They  are  named  from  the  position  which  they  may 
chance  to  occupy  upon  the  surface  of  this  organ,  either  superior  or 
inferior,  internal  or  external,  anterior  or  posterior. 

The  Superior  cerebral  veins,  seven  or  eight  in  number  on  each 
side,  pass  obliquely  forwards,  and  terminate  in  the  superior  longitu- 
dinal sinus,  in  the  opposite  direction  to  the  course  of  the  stream  of 
blood  in  the  sinus. 

The  Deej)  or  Ventricular  veins  commence  within  the  lateral  ven- 
tricles by  two  vessels,  the  vena  corporis  striati  and  the  veins  of  the 
choroid  plexus,  which  unite  to  form  the  two  vense  Galeni. 

The  Fence  Galeni  pass  backwards  in  the  structure  of  the  velum 
interpositum  ;  and  escaping  through  the  fissure  of  Bichat,  terminate 
in  the  straight  sinus. 

The  Cerebellar  veins  are  disposed,  like  those  of  the  cerebrum,  on 
the  surface  of  the  lobes  of  the  cerebellum  ;  they  are  situated  some 
upon  the  superior,  and  some  upon  the  inferior  surface,  while  others 
occupy  the  borders  of  the  organ.  They  terminate  in  the  lateral 
and  petrosal  sinuses. 

SINUSES    OF    THE    DURA    MATER. 

The  sinuses  of  the  dura  mater  are  irregular  channels,  formed  by 
the  splitting  of  the  layers  of  that  membrane,  and  lined  upon  their 
inner  surface  by  a  continuation  of  the  serous  layer  of  the  veins. 
They  may  be  divided  into  two  groups: — 1.  Those  situated  at  the 
upper  and  back  part  of  the  skull.  2.  The  sinuses  at  the  base  of  the 
skull.     The  former  are,  the — 

Superior  longitudinal  sinus, 
Inferior  longitudinal  sinus, 
Straight  sinus,  or  sinus  quartus, 
Occipital  sinuses, 
Lateral  sinuses. 

The  Superior  longitudinal  sinus,  is  situated  in  the  attached  margin 
of  the  falx  cerebri,  and  extends  along  the  middle  line  of  the  arch  of 
the  skull,  from  the  foramen  caecum  in  the  frontal,  to  the  inner  tube- 
rosity of  the  occipital  bone,  where  it  divides  into  the  two  lateral 
sinuses.  It  is  triangular  in  form,  is  small  in  front,  and  increases 
gradually  in  size  as  it  passes  backwards  ;  it  receives  the  superior 
cerebral  veins  which  open  into  it  obliquely,  numerous  small  veins 
from  the  diploe,  and  near  the  posterior  extremity  of  the  sagittal 
suture  the  parietal  veins,  from  the  pericranium  and  scalp.  Examined 
upon  its  interior,  it  presents  numerous  transverse  fibrous  bands,  the 
chordae  Willisii,  which  are  stretched  across  its  inferior  angle;  and 
some  small  white  granular  masses,  the  glandular  Pacchioni ;  the 
oblique  openings  of  the  cerebral  veins,  with  their  valve-like  margin, 
are  also  seen  upon  the  walls  of  the  sinus. 


INFERIOR  LONGITUDINAL  SINUS. 


357 


The  termination  of  the  superior  longitudinal  sinus  in  the  two 
lateral  sinuses  forms  a  considerable  dilatation,  into  which  the  straight 
sinus  opens  from  the  front,  and  the  occipital  sinuses  from  below. 
This  dilatation  is  named  the  torcular  Herophili,*  and  is  the  point  of 
communication  of  six  sinuses — the  superior  longitudinal,  two  lateral, 
two  occipital,  and  the  straight. 

Fig,  134. 


The  Inferior  longitudinal  sinus  is  situated  in  the  free  margin  of 
the  falx  cerebri ;  it  is  cylindrical  in  form  and  extends  from  near  the 
crista  galli  to  the  anterior  border  of  the  tentorium,  where  it  termi- 
nates in  the  straight  sinus.  It  receives  in  its  course  several  veins 
from  the  falx. 

The  straight  or  fourth  sinus  is  the  sinus  of  the  tentorium  ;  it  is 
situated  at  the  line  of  union  of  the  falx  with  the  tentorium ;  is  pris- 
moid  in  form,  and  extends  across  the  tentorium,  from  the  termina- 
tion of  the  inferior  longitudinal  sinus  to  the  torcular  Herophili.  It 
receives  the  venae  Galeni,  the  cerebral  veins  from  the  inferior  part 
of  the  posterior  lobes,  and  the  superior  cerebellar  veins. 

The  Occipital  sinuses  are  two  canals  of  small  size,  situated  in  the 
attached  border  of  the  falx  cerebelli ;  they  commence  by  several 
small  veins  around  the  foramen  magnum,  and  terminate  by  separate 
openings  in  the  torcular  Herophili.  They  not  unfrequently  commu- 
nicate with  the  termination  of  the  lateral  sinuses. 


Fig.  134.  The  sinuses  of  the  upper  and  back  part  of  the  skull.  1.  The  superior 
longitudinal  sinus,  2,  2.  The  cerebral  veins  opening  into  the  sinus  from  beliind  for- 
wards. 3.  Tlie  falx  cerebri.  4.  The  inferior  longitudinal  sinus,  .5.  The  straight  or 
fourth  sinus.  6,  The  venae  Galeni.  7.  The  torcular  Herophili.  8.  The  two  lateral 
sinuses  with  the  occipital  sinuses  between  them,  9.  The  termination  of  the  inferior 
petrosal  sinus  of  one  side.  10.  The  dilatations  corresponding  with  the  jugular  fossaj, 
11.  The  internal  jugular  veins. 

*  Torcular  (a  press),  from  a  supposition  entertained  by  the  older  anatomists  that  the 
columns  of  blood,  coming  in  different  directions,  compressed  each  other  at  this  point. 


358 


LATERAL  SINUSES. 


The  Lateral  sinuses,  commencing  at  the  torcular  Herophili,  pass 
horizontally  outwards,  in  the  attached  margin  of  the  tentorium,  and 
curve  downwards  and  inwards  along  the  base  of  the  petrous  portion 
of  the  temporal  bone,  at  each  side,  to  the  foramina  lacera  posteriora, 
where  they  terminate  in  the  internal  jugular  veins.  Each  sinus  rests 
successively  in  its  course  upon  the  transverse  groove  of  the  occipital 
bone,  posterior  inferior  angle  of  the  parietal,  mastoid  portion  of  the 
temporal,  and  again  on  the  occipital  bone.  They  receive  the  cerebral 
veins  from  the  inferior  surface  of  the  posterior  lobes,  the  inferior 
cerebellar  veins,  the  superior  petrosal  sinuses,  the  mastoid,  and  pos- 
terior condyloid  veins,  and,  at  their  termination,  the  inferior  petrosal 
sinuses.  These  sinuses  are  often  unequal  in  size,  the  right  being 
much  larger  than  the  left. 

Fig.  135. 


The  sinuses  of  the  base  of  the  skull  are  the — 

Cavernous, 
Inferior  petrosal, 
Circular, 

Superior  petrosal, 
Transverse. 

The  Cavernous  sinuses  are  named  from  presenting  a  cellular  struc- 
ture in  their  interior.     They  are  situated  on  each  side  of  the  sella 

Fig.  135.  The  sinuses  of  the  base  of  the  skull.  1.  The  ophthalmic  veins.  2.  The 
cavernous  sinus  of  one  side.  3.  The  circular  sinus  ;  the  figure  occupies  the  position  of 
the  pituitary  gland  in  the  sella  turcica.  4.  The  inferior  petrosal  sinus.  5.  The  trans- 
verse or  anterior  occipital  sinus.  6.  The  superior  pelrosal  sinus.  7.  The  internal 
jugular  vein.  8.  The  foramen  magnum.  9.  The  occipital  siauses.  10.  The  torcular 
Herophili.     11,  11.  The  lateral  sinuses. 


VEINS  OF  THE  NECK.  359 

turcica,  receiving,  anteriorly,  the  opjithalnriic  veins  througii  the 
sphenoidal  fissures,  and  terminating  posteriorly  in  the  inferior  petrosal 
sinuses.  In  the  internal  wall  of  each  cavernous  sinus  is  the  internal 
carotid  artery,  accompanied  by  several  filaments  of  the  carotid 
plexus,  and  crossed  by  the  sixth  nerve;  and, in  its  external  wall,  the 
third,  fourth,  and  ophthalmic  nerves.  These  structures  are  separated 
from  the  blood  flowing  through  the  sinus,  by  the  tubular  lining 
membrane.  The  cerebral  veins  from  the  under  surface  of  the  ante- 
rior lobes,  open  into  the  cavernous  sinuses.  They  communicate  by 
means  of  the  ophthalmic  veins  with  the  facial  veins,  by  the  circular 
sinus  with  each  other,  and  by  the  superior  petrosal  with  the  lateral 
sinuses. 

The  Inferior  petrosal  sinuses  are  the  continuations  of  the  cavern- 
ous sinuses  backwards  along  the  lower  border  of  the  petrous  por- 
tion of  the  temporal  bone  at  each  side  of  the  base  of  the  skull,  to 
the  foramina  lacera  posteriora,  where  they  terminate  with  the  lateral 
sinuses  in  the  commencement  of  the  internal  jugular  veins. 

The  Circular  sinus  is  situated  in  the  sella  turcica,  surrounding  the 
pituil;ary  gland,  and  communicates  on  each  side  with  the  cavernous 
sinus. 

The  Superior  petrosal  sinuses  pass  obliquely  backwards  along  the 
attached  border  of  the  tentorium,  on  the  upper  margin  of  the  petrous 
portion  of  the  temporal  bone,  and  establish  a  communication  between 
the  cavernous  and  lateral  sinus  at  each  side.  They  receive  one  or 
two  cerebral  veins  from  the  inferior  part  of  the  middle  lobes,  and  a 
cerebellar  vein  from  the  anterior  border  of  the  cerebellum. 

The  Transverse  sinus  (basilar,  anterior  occipital)  passes  trans- 
versely across  the  basilar  process  of  the  occipital  bone,  forming  a 
communication  between  the  two  inferior  petrosal  sinuses. 

VEINS    OF     THE     NECK. 

The  veins  of  the  neck  which  return  the  blood  from  the  head  are 
the— 

External  jugular, 
Anterior  jugular, 
Internal  jugular, 
Vertebral. 

The  External  jugular  vein  is  formed  by  the  union  of  the  pos- 
terior auricular  vein  with  the  temporo-maxillary,  and  commences 
at  the  lower  border  of  the  parotid  gland,  in  front  of  the  sterno-mas- 
toid  muscle.  It  descends  the  neck  in  the  direction  of  a  line  drawn 
from  the  angle  of  the  lower  jaw  to  the  middle  of  the  clavicle,  crosses 
the  sterno-mastoid,  and  terminates  near  the  posterior  and  inferior 
attachment  of  that  muscle  in  the  subclavian  vein.  In  its  course 
downwards  it  lies  upon  the  anterior  lamella  of  the  deep  cervical 
fascia,  which  separates  it  from  the  sterno-mastoid  muscle,  and  is 


360  VEINS  OF  THE   NECK. 

covered  in  by  the  platysma  myoides  and  superficial  fascia.  At  the 
root  of  the  neck  it  pierces  the  deep  cervical  fascia  ;  it  is  accom- 
panied, for  the  upper  half  of  its  course,  by  the  auricularis  magnus 
nerve.  The  branches  which  it  receives  are  the  occipital  and  pos- 
terior cervical  cutaneous,  and,  near  its  termination,  the  supra  and 
posterior  scapular. 

The  external  jugular  vein  is  very  variable  in  size,  and  is  occa- 
sionally replaced  by  two  veins.  In  the  parotid  gland  it  receives  a 
large  communicating  branch  from  the  internal  jugular  vein. 

The  Anterior  jugular  vein  is  a  trunk  of  variable  size,  which  col- 
lects the  blood  from  the  integument  and  superficial  structures  on 
the  fore  part  of  the  neck.  It  passes  downwards  along  the  anterior 
border  of  the  sterno-mastoid  muscle,  and  opens  into  the  subclavian 
vein,  near  to  the  termination  of  the  external  jugular.  The  two  veins 
communicate  with  each  other,  with  the  external  and  with  the  in- 
ternal jugular  vein. 

The  Internal  jugular  vein,  formed  by  the  convergence  of  the 
lateral  and  inferior  petrosal  sinus,  commences  at  the  foramen 
lacerum  posterius  on  each  side  of  the  base  of  the  skull,  and  descends 
the  side  of  the  neck,  lying,  in  the  first  instance,  to  the  outer  side  of 
the  internal  carotid,  and  then  upon  the  outer  side  of  the  common 
carotid  artery,  to  the  root  of  the  neck,  where  it  unites  with  the 
subclavian,  and  constitutes  the  vena  innominata.  At  its  com- 
mencement, the  internal  jugular  vein  is  posterior  and  external  to  the 
internal  carotid  artery,  and  to  the  eighth  and  ninth  pairs  of  nerves; 
lower  down,  the  vein  and  artery  are  on  the  same  plane,  the  glosso- 
pharyngeal and  hypoglossal  nerves  passing  forwards  between  them, 
the  pneumogastric  being  between  and  behind  in  the  same  sheath, 
and  the  nervus  accessorius  crossing  obliquely  behind  the  vein. 

The  Branches  which  the  internal  jugular  receives  in  its  course 
are,  the  facial,  the  lingual,  the  inferior  pharyngeal,  the  occipital,  and 
the  superior  and  inferior  thyroid  veins. 

The  Vertebral  vein  descends  by  the  side  of  the  vertebral  artery 
4n  the  canal  formed  by  the  foramina  in  the  transverse  processes  of 
the  cervical  vertebrse,  and  terminates  at  the  root  of  the  neck  in  the 
commencement  of  the  vena  innominata.  In  the  lower  part  of  the 
vertebral  canal  it  frequently  divides  into  two  branches,  one  of  which 
advances  forwards,  while  the  other  passes  through  the  foramen  in 
the  transverse  process  of  the  seventh  cervical  vertebra,  before 
opening  into  the  vena  innominata. 

The  Branches  which  it  receives  in  its  course  are  the  posterior 
condyloid  vein,  muscular  branches,  the  cervical  meningo-rachidian 
veins,  and,  near  its  termination,  the  superficial  and  deep  cervical 
veins. 

The  Inferior  thyroid  veins,  two,  and  frequently  more  in  number, 
are  situated  on  one  side  of  the  trachea,  and  receive  the  venous 
blood  from  the  thyroid  gland.  They  communicate  with  each  other 
and  with  the  superior  thyroid  veins,  and  form  a  plexus  upon  the 


VEINS  OF  THE  UPPER  EXTREMITY.  361 

front  of  the  trachea.  The  right  vein  terminates  in  the  right  vena 
innominata,  just  at  its  union  with  the  superior  cava,  and  the  left  in 
the  left  vena  innominata. 


VEINS    OF     THE     UPPER     EXTREMITY. 

The  veins  of  the  upper  extremity  are  the  deep  and  superficial. 
The  deep  veins  accompany  the  branches  and  trunks  of  the  arteries, 
and  constitute  their  venm  comites.  The  vena3  comites  of  the  radial 
and  ulnar  arteries  are  enclosed  in  the  same  sheath  with  those  ves- 
sels, and  terminate  at  the  bend  of  the  elbow  in  the  brachial  veins. 
The  brachial  venae  comites  are  situated  one  on  each  side  of  the 
artery,  and  open  into  the  axillary  vein ;  the  axillary  becomes  the 
subclavian,  and  the  subclavian  unites  with  the  internal  jugular  to 
form  the  vena  innominata. 

The  Superficial  veins  of  the  fore-arm  are  the — 

Anterior  ulnar  vein. 
Posterior  ulnar  vein, 
Basilic  vein. 
Radial  vein, 
Cephalic  vein, 
Median  vein. 
Median  basilic. 
Median  cephalic. 

The  Anterior  ulnar  vein  collects  the  venous  blood  from  the  inner 
border  of  the  hand,  and  from  the  vein  of  the  little-finger,  vena  sal- 
vatella,  and  ascends  the  inner  side  of  the  fore-arm  to  the  bend  of 
the  elbow,  where  it  becomes  the  basilic  vein. 

The  Posterior  ulnar  vein,  irregular  in  size  and  frequently  absent, 
commences  also  upon  the  inner  border  and  posterior  aspect  of  the 
hand,  and,  ascending  the  fore-arm,  terminates  in  front  of  the  inner 
condyle,  in  the  anterior  ulnar  vein. 

The  Basilic  vein  (fSaJi'kmg,  royal,  or  principal)  ascends  from  the 
common  ulnar  vein,  formed  by  the  two  preceding,  along  the  inner 
side  of  the  upper  arm,  and  near  its  middle  pierces  the  fascia ;  it 
then  passes  upwards  to  the  axilla,  and  becomes  the  axillary  vein. 

The  Radial  vein  commences  in  the  large  vein  of  the  thumb,  on 
the  outer  and  posterior  aspect  of  the  hand,  and  ascends  along  the 
outer  border  of  the  fore-arm  to  the  bend  of  the  elbow,  where  it 
becomes  the  cephalic  vein. 

The  Cephalic  vein  (xscpakrj,  the  head)  ascends  along  the  outer 
side  of  the  arm  to  its  upper  third ;  it  then  enters  the  groove 
between  the  pectoralis  major  and  deltoid  muscles,  where  it  is  in  rela- 
tion with  the  descending  branch  of  the  thoracico-acromialis  artery, 
and  terminates  beneath  the  clavicle  in  the  subclavian  vein.  A 
large  communicating   branch   sometimes  crosses  the  clavicle  be- 

31 


362 


AXILLARY  VEIN SUBCLAVIAN  VEIN. 


Fig.  136. 


tween  the  external  jugular  and  this  vein,  which  gives  it  the  appear- 
ance of  being  derived  directly  from  the  head — hence  its  appellation. 
The  Median  vein  is  intermediate  between 
the  anterior  ulnar  and  radial  vein ;  it  collects 
the  blood  from  the  anterior  aspect  of  the 
fore-arm,  communicating  with  the  two  pre- 
ceding. At  the  bend  of  the  elbow  it  receives 
a  branch  from  the  deep  veins,  and  divides 
into  two  branches,  the  median  cephalic  and 
median  basilic. 

The  Median  cephalic  vein,  generally  the 
smaller  of  the  two,  passes  obliquely  outwards, 
in  the  groove  between  the  biceps  and  the 
supinator  longus,  to  join  the  cephalic  vein. 
The  branches  of  the  external  cutaneous  nerve 
pass  behind  it. 

The  Median  basilic  vein  passes  obliquely 
inwards,  in  the  groove  between  the  biceps 
and  pronator  radii  teres,  and  terminates  in 
the  basilic  vein.  This  vein  is  crossed  by  one 
or  two  filaments  of  the  internal  cutaneous 
nerve,  and  is  separated  from  the  brachial 
artery  by  the  aponeurotic  slip  given  off  by 
the  tendon  of  the  biceps. 


AXILLARY     VEIN. 

The  axillary  vein  is  formed  by  the  union  of  the  vena3  comites  of 
ihe  brachial  artery  with  the  basilic  vein.  It  lies  in  front  of  the 
artery,  and  receives  numerous  branches  from  the  collateral  veins 
of  the  branches  of  the  axillary  artery,  and,  at  the  lower  border  of 
the  first  rib  becomes  the  subclavian  vein. 

SUBCLAVIAN     VEIN. 

The  subclavian  vein  crosses  over  the  first  rib  and  beneath  the 
clavicle,  and  unites  with  the  internal  jugular  vein  to  form  the  vena 
innominata.  It  lies  at  first  in  front  of  the  subclavian  artery,  and 
then  in  front  of  the  scalenus  anticus,  which  separates  it  from  that 
vessel.     The  phrenic  and  pneumogastric  nerves  pass  between  the 


Fig.  136.  The  veins  of  the  fore-arm  and  bend  of  the  elbow,  1.  The  radial  vein. 
2.  Tlie  cephalic  vein.  3.  The  anterior  ulnar  vein.  4.  The  posterior  ulnar  vein.  5. 
The  trunk  formed  by  their  union.  6.  The  basilic  vein,  piercing-  the  deep  fascia  at  7. 
8.  The  median  vein.  9.  A  communicating  branch  between  tiie  deep  veins  of  the  fore- 
arm and  the  upper  part  of  the  median  vein.  10.  The  median  cephalic  vein.  11.  The 
median  basilic.  12.  A  slijrht  convexity  of  the  deep  fascia,  formed  by  the  brachial 
artery.  13.  The  process  of  fasciu,  derived  from  the  tendon  of  the  biceps,  and  sepa- 
rating the  median  basilic  vein  from  the  brachial  artery.  14.  The  external  cutaneous 
nerve,  piercing  the  deep  fascia,  and  dividing  into  two  branches,  which  pass  behind  the 
median  cephalic  vein.  1.5.  The  internal  cutaneous  nerve,  dividing  into  branches, 
which  pass  in  front  of  the  median  basilic  vein.  16.  The  intcrcosto-humeral  cutaneous 
nerve.     17.  The  spiral  cutaneous  nerve,  a  branch  of  the  musculo-spiral. 


VEINS  OF  THE  LOWER  EXTBEMITY.  363 

artery  and  vein.  The  veins  opening  into  the  subclavian  are  the 
cephalic  below  the  clavicle,  and  the  external  and  anterior  jugulars 
above ;  occasionally  some  small  veins  from  the  neighbouring  parts 
also  terminate  in  it. 

VEINS     OF     THE     LOWER     EXTREMITY. 

The  veins  of  the  lower  extremity  are  the  deep  and  superficial. 
The  deej)  veins  accompany  the  branches  of  the  arteries  in  pairs, 
and  form  the  venae  comites  of  the  anterior  and  posterior  tibial  and 
peroneal  arteries.  These  veins  unite  in  the  popliteal  region  to  form 
a  single  vein  of  large  size — the  popliteal — which  successively  be- 
comes in  its  course  the  femoral  and  the  external  iliac  vein. 

POPLITEAL     VEIN. 

The  popliteal  vein  ascends  through  the  popliteal  region,  lying, 
in  the  first  instance,  directly  upon  the  artery,  and  then  getting  some- 
what to  its  outer  side.  It  receives  several  muscular  and  articular 
veins,  and  the  external  saphenous  vein.  The  valves  in  this  vein 
are  four  or  five  in  number. 

FEMORAL     VEIN. 

The  femoral  vein,  passing  through  the  opening  in  the  adductor 
magnus  muscle,  ascends  the  thigh  in  the  sheath  of  the  femoral  artery, 
and  entering  the  pelvis  beneath  Poupart's  ligament,  becomes  the 
external  iliac  vein.  In  the  lower  part  of  its  course  it  is  situated 
upon  the  outer  side  of  the  artery ;  it  then  becomes  placed  behind 
that  vessel,  and,  at  Poupart's  ligament,  lies  to  its  inner  side.  It 
receives  the  muscular  veins,  and  the  profunda,  and,  through  the 
saphenous  opening,  the  internal  saphenous  vein.  The  valves  in  this 
vein  are  four  or  five  in  number. 

The  Profunda  vein  is  formed  by  the  convergence  of  the  numerous 
small  veins  which  accompany  the  branches  of  the  artery ;  it  is  a 
vein  of  large  size,  lying  in  front  of  the  profunda  artery,  and  ter- 
minates in  the  femoral  at  about  an  inch  and  a  half  below  Poupart's 
ligament. 

The  Superficial  veins  are  the  external  or  short,  and  the  internal 
or  long  saphenous. 

The  External  saphenous  vein  collects  the  blood  from  the  outer 
side  of  the  foot  and  leg.  It  passes  behind  the  outer  ankle,  ascends 
along  the  posterior  aspect  of  the  leg,  lying  in  the  groove  between 
the  two  bellies  of  the  gastrocnemius  muscle,  and  pierces  the  deep 
fascia  in  the  popliteal  region  to  join  the  popliteal  vein.  It  receives 
several  cutaneous  branches  in  the  popliteal  region  before  passing 
through  the  deep  fascia,  and  is  accompanied  in  its  course  by  the 
external  saphenous  nerve. 

The  Internal  saphenous  vein  commences  upon  the  dorsum  and 
inner  side  of  the  foot.  It  ascends  in  front  of  the  inner  ankle,  and 
along  the  inner  side  of  the  leg ;  it  then  passes  behind  the  inner  con- 
dyle of  the  femur,  and  along  the  inner  side  of  the  thigh  to  the  saphe- 


364  SUPERIOR  VENA  CAVA, 

nous  opening,  where  it  pierces  the  sheath  of  the  femoral  vessels,  and 
terminates  in  the  femoral  vein,  at  about  one  inch  and  a  half  below 
Poupart's  ligament. 

It  receives  in  its  course  the  cutaneous  veins  of  the  leg  and  thigh, 
and  communicates  freely  with  the  deep  veins.  At  the  saphenous 
opening  it  is  joined  by  the  superficial  epigastric  and  circumflexailii 
veins,  and  by  the  external  pudic.  The  situation  of  this  vein  in  the 
thigh  is  not  unfrequently  occupied  by  two  or  even  three  trunks  of 
nearly  equal  size. 

VEINS     OF     THE     TRUNK. 

The  veins  of  the  trunk  may  be  divided  into  1.  The  superior  vena 
cava,  with  its  formative  branches.  2.  The  inferior  vena  cava,  with 
its  formative  branches.  3.  The  azygos  veins.  4.  The  vertebral 
and  spinal  veins.  5.  The  cardiac  veins.  6.  The  portal  vein.  7. 
The  pulmonary  veins. 

SUPERIOR    VENA    CAVA,    WITH    ITS     FORMATIVE    BRANCHES. 

VencB  InnominatcB. 

The  VencB  innominate  are  two  large  trunks,  formed  by  the  union 
of  the  internal  jugular  and  subclavian  vein,  at  each  side  of  the  root 
of  the  neck. 

The  Right  vena  innominata,  about  an  inch  and  a  quarter  in  length, 
lies  superficially  and  externally  to  the  arteria  innominata,  and 
descends  almost  vertically,  to  unite  with  its  fellow  of  the  opposite 
side  in  the  formation  of  the  superior  cava.  At  the  junction  of  the 
jugular  and  subclavian  veins  it  receives  from  behind  the  ductus  lym- 
phaticus  dexter,  and  lower  down  it  has  opening  into  it  the  right 
vertebral,  right  internal  mammary,  and  right  inferior  thyroid  vein. 

The  Left  vena  innominata,  considerably  longer  than  the  right, 
extends  almost  horizontally  across  ihe  roots  of  the  three  arteries 
arising  from  the  arch  of  the  aorta,  to  the  right  side  of  the  mediastinum, 
where  it  unites  with  the  right  vena  innominata,  to  constitute  the 
superior  cava. 

It  is  in  relation  in  front  with  the  left  stemo-clavicular  articulation 
and  the  first  piece  of  the  sternum.  At  its  commencement  it  receives 
the  thoracic  duct,  which  opens  into  it  from  behind,  and  in  its  course 
is  joined  by  the  left  vertebral,  left  inferior  thyroid,  left  mammary  and 
by  the  superior  intercostal  vein.  It  also  receives  some  small  veins 
from  the  mediastinum  and  thymus  gland.  There  are  no  valves  in 
the  vcnffi  innominatoe. 

SUPERIORVENACAVA. 

The  superior  cava  is  a  short  trunk  about  three  inches  in  length, 
formed  by  the  junction  of  the  two  veno3  innominatse.  It  descends 
perpendicularly  on  the  right  side  of  the  mediastinum,  and  entering 
the  pericardium  terminates  in  the  upper  part  of  the  right  auricle. 

It  is  in  relation  in  front  with  the  thoracic  fascia,  which  separates 
it  from  the  thymus  gland,  and  with  the  pericardium  ;  behind  with 
the  right  pulmonary  artery,  and  the  right  superior  pulmonary  vein  ; 


INFERIOR  VENA  CAVA. 


365 


Fig.  137. 


internally  with  the  ascending  aorta  ;  externally  with  the  right  phre- 
nic nerve,  and  right  lung.  Immediately  before  entering  the  peri- 
cardium it  receives  the  vena  azygos  major. 

INFERIOR   VENA     CAVA,     WITH     ITS     FORMATIVE     BRANCHES. 

Iliac  Veins. 

The  External  iliac  vein  lies  to  the  inner  side  of  the  corresponding 
artery  at  the  os  pubis  ;  but  gradually  gets 
behind  it  as  it  passes  upwards  along  the 
brim  of  the  pelvis,  and  terminates  oppo- 
site the  sacro-iliac  symphysis  by  uniting 
with  the  internal  iliac,  to  form  the  com- 
mon iliac  vein.  Immediately  above  Pou- 
part's  ligament  it  receives  the  epigastric 
and  the  circumflexa  ilii  veins;  it  has  no 
valves. 

The  Internal  iliac  vein  is  formed  by 
vessels  which  correspond  with  the  bran- 
ches of  the  internal  iliac  artery;  it  re- 
ceives the  returning  blood  from  the  gluteal, 
ischiatic,  internal  pudic,  and  obturator 
veins,  externally  to  the  pelvis;  and  from 
the  vesical  and  uterine  plexuses  within 
the  pelvis.  The  vein  lies  to  the  inner 
side  of  the  internal  iliac  artery,  and  ter- 
minates by  uniting  with  the  external  iliac 
vein,  to  form  the  common  iliac. 

The  Vesical  and  prostatic  plexus  is  an 
important  plexus  of  veins  which  surrounds 
the  neck  and  base  of  the  bladder  and  pro- 
state gland,  and  receives  its  blood  from 
the  great  dorsal  vein  of  the  penis,  and 
from  the  veins  of  the  external  organs  of 
generation.  It  is  retained  in  connexion 
with  the  sides  of  the  bladder  by  a  reflec- 
tion of  the  pelvic  fascia. 

The  Uterine  plexus  is  situated  around 
the  vagina,  and  upon  the  sides  of  the 
uterus,   between   the  two  layers  of  the 

Fig.  137.  The  veins  of  the  trunk  and  neck.  1.  The  superior  vena  cava.  2.  The 
left  vena  innominata.  3.  The  right  vena  innominata.  4.  The  right  subclavian  vein. 
5.  The  internal  jugular  vein.  6.  The  external  jugular.  7.  The  anterior  jugular.  8. 
The  inferior  vena  cava.  9.  The  external  iliac  vein.  10.  The  internal  iliac  vein.  11. 
The  common  iliac  veins;  the  small  vein  between  these  is  the  vena  sacra  media.  12, 
12.  Lumbar  veins.  13.  The  right  spermatic  vein.  14.  The  left  spermatic,  opening 
into  the  left  renal  vein.  15.  The  right  renal  vein.  16.  The  trunk  of  the  hepatic  veins. 
17.  The  greater  vena  azygos,  commencing  inferiorly  in  the  lumbar  veins.  J8.  The 
lesser  vena  azygos,  also  commencing  in  the  lumbar  veins.  19.  A  branch  of  communi- 
cation  with  the  left  renal  vein.  20.  The  termination  of  the  lesser  in  the  greater  vena 
azygos.  21.  The  superior  intercostal  vein ;  communicating  inferiorly  with  the  lesser 
vena  axygos,  and  terminating  superiorly  in  the  left  vena  innominata. 

31* 


366  INFERIOR  VENA  CAVA. 

broad  ligaments.     The  veins  forming  the  vesical  and  uterine  plexus  ' 
are  very  subject  to  the  production  of  phlebolitis. 

The  Commo?i  iliac  vei?is  are  formed  by  the  union  of  the  external 
and  internal  iliac  vein  on  each  side  of  the  pelvis.  The  j'ight  common 
iliac,  shorter  than  the  left,  ascends  obliquely  behind  the  correspond- 
ing artery ;  and  upon  the  intervertebral  substance  between  the  fourth 
and  fifth  lumbar  vertebras,  unites  with  the  vein  of  the  opposite  side, 
to  form  the  inferior  cava.  The  left  common  iliac,  longer  and  more 
oblique  than  the  right,  ascends  behind  and  a  little  internally  to  the 
corresponding  artery,  and  passes  beneath  the  right  common  iliac 
artery,  near  to  its  origin,  to  unite  with  ihe  right  vein  in  the  forma- 
tion of  the  inferior  vena  cava.  The  right  common  iliac  vein  has 
no  branch  opening  into  it;  the  left  receives  the  vena  sacra  media. 
These  veins  have  no  valves. 

INFERIOR     VENA     CAVA. 

The  inferior  vena  cava  is  formed  by  the  union  of  the  two  common 
iliac  veins,  upon  the  intervertebral  substance  between  the  fourth 
and  fifth  lumbar  vertebra.  It  ascends  along  the  front  of  the  vertebral 
column,  on  the  right  side  of  the  abdominal  aorta,  and  passing  through 
the  fissure  in  the  posterior  border  of  the  liver  and  the  quadrilateral 
opening  in  the  tendinous  centre  of  the  diaphragm,  terminates  in  the 
inferior  and  posterior  part  of  the  right  auricle.  There  are  no  valves 
in  this  vein. 

It  is  in  relation  from  below  upwards,  in /row^  with  the  mesentery, 
transverse  duodenum,  portal  vein,  pancreas  and  liver,  which  nearly 
and  sometimes  completely  surround  it ;  behind  it  rests  upon  the 
vertebral  column  and  right  crus  of  the  diaphragm,  from  which  it  is 
separated  by  the  right  renal  and  lumbar  arteries ;  to  the  right  it  has 
the  peritoneum  and  sympathetic  nerve;  and  to  the  left  the  aorta. 

The  Branches  which  the  inferior  cava  receives  in  its  course,  are 
the— 

Lumbar, 

Right  spermatic, 

Renal, 

Supra-renal, 

Phrenic, 

Hepatic. 

The  Lumbar  veins,  three  or  four  in  number  on  each  side,  collect 
the  venous  blood  from  the  muscles  and  integument  of  the  loins,  and 
from  the  spinal  veins;  the  left  are  longer  than  the  right  from  the 
position  of  the  vena  cava. 

The  Right  spermatic  vein  is  formed  by  the  two  veins  which  re- 
turn the  blood  from  the  venous  plexus,  situated  in  the  spermatic 
cord.  These  veins  follow  the  course  of  the  spermatic  artery,  and 
unite  to  form  the  single  trunk  which  opens  into  the  inferior  vena 
cava.     The  left  spermatic  vein  terminates  in  the  left  renal  vein. 

The  Ovarian  veins  represent  the  spermatic  veins  of  the  male,  and 


AZYGOS  VEINS.  367 

collect  the  venous  blood  from  the  ovaries,  round  ligaments,  and 
Fallopian  tubes,  and  communicate  with  the  uterine  sinuses.  They 
terminate  as  in  the  male. 

The  Renal  or  emiilgent  veins  return  the  blood  from  the  kidneys  ; 
their  branches  are  situated  in  front  of  the  divisions  of  the  renal 
arteries,  and  the  left  opens  into  the  vena  cava  somewhat  higher  than 
the  right.  The  left  is  longer  than  the  right  in  consequence  of  the 
position  of  the  vena  cava,  and  crosses  the  aorta  immediately  below 
the  origin  of  the  superior  mesenteric  artery.  It  receives  the  left 
spermatic  vein,  which  terminates  in  it  at  right  angles :  hence  the 
more  frequent  occurrence  of  varicocele  on  the  left  than  on  the  right 
side. 

The  Swpra-renal  veins  terminate  partly  in  the  renal  veins,  and 
partly  in  the  inferior  vena  cava. 

The  Phrenic  veins  return  the  blood  from  the  ramifications  of  the 
phrenic  arteries ;  they  open  into  the  inferior  cava. 

The  Hepatic  veins  form  two  principal  trunks  and  numerous  smaller 
veins  which  open  into  the  inferior  cava,  while  that  vessel  is  situated 
in  the  posterior  border  of  the  liver.  The  hepatic  veins  commence 
in  the  liver  by  minute  venules,  the  intralobular  veins  in  the  centre  of 
each  lobule ;  these  pour  their  blood  into  larger  vessels,  the  suhlohular 
veins;  and  the  sublobular  veins  constitute  by  their  convergence  and 
union,  the  hepatic  trunks,  which  terminate  in  the  inferior  vena  cava. 

AZYGOS    VEINS. 

The  azygos  veins  form  a  system  of  communication  between  the 
superior  and  inferior  vena  cava,  and  serve  to  return  the  blood  from 
that  part  of  the  trunk  in  which  those  vessels  are  deficient,  on  account 
of  their  connexion  with  the  heart.  This  system  consists  of  three 
vessels,  the — 

Vena  azygos  major, 
Vena  azygos  minor, 
Superior  intercostal  vein. 

The  Vena  azygos  major  commences  in  the  lumbar  region  by  a 
communication  with  the  lumbar  veins;  sometimes  it  is  joined  by  a 
branch  directly  from  the  inferior  vena  cava,  or  by  one  from  the 
renal  vein.  It  passes  through  the  aortic  opening  in  the  diaphragm, 
and  ascends  upon  the  right  side  of  the  vertebral  column  to  the  third 
dorsal  vertebra,  where  it  arches  forwards  over  the  right  bronchus, 
and  terminates  in  the  superior  cava.  It  receives  all  the  intercostal 
veins  of  the  right  side,  the  vena  azygos  minor,  and  the  bronchial 
veins. 

The  Vena  azygos  minor  commences  in  the  lumbar  region,  on  the 
left  side,  by  a  communication  with  the  lumbar  or  renal  veins.  It 
passes  beneath  the  border  of  the  diaphragm,  and  ascending  upon 
the  left  side  of  the  vertebral  column  crosses  the  fifth  or  sixth  dorsal 
vertebra  to  open  into  the  vena  azygos  major.     It  receives  the  six 


368  VERTEBHAL  AND  SPINAL  VEINS. 

or  seven  lower  intercostal  veins  of  the  left  side.     The  azygos  veins 
have  no  valves. 

The  Superior  intercostal  vein  is  the  trunk  formed  by  the  union  of 
the  five  or  six  upper  intercostal  veins  of  the  left  side.  It  communi- 
cates below  with  the  vena  azygos  minor,  and  ascends  to  terminate 
in  the  left  vena  innominata. 

VERTEBRAL     AND     SPINAL     VEINS. 

The  numerous  venous  plexuses  of  the  vertebral  column  and  spinal 
cord  may  be  arranged  into  three  groups : — 

Dorsi-spinal, 

Meningo-rachidian, 

Medulli-spinal. 

The  Dorsi-spinal  veins  form  a  plexus  around  the  spinous,  trans- 
verse and  articular  processes  and  arches  of  the  vertebrae.  They 
receive  the  returning  blood  from  the  dorsal  muscles  and  surrounding 
structures,  and  transmit  it,  in  part  to  the  meningo-rachidian,  and  in 
part  to  the  vertebral,  intercostal,  lumbar,  and  sacral  veins.  ■ 

The  Meningo-rachidian  veins  are  situated  between  thetheca  ver- 
tebralis  and  the  vertebrae.  They  communicate  freely  with  each 
other  by  means  of  a  complicated  plexus.  In  front  they  form  two 
longitudinal  trunks,  which  extend  the  whole  length  of  the  column  on 
each  side  of  the  posterior  common  ligament,  and  are  joined  on  the 
body  of  each  vertebra  by  transverse  trunks,  which  pass  beneath  the 
ligament,  and  receive  the  large  vertebral  veins  from  the  interior  of 
each  vertebra.  They  pour  their  blood  into  the  vertebral  veins  in 
the  neck,  into  the  intercostal  veins  in  the  thorax,  and  into  the  lumbar 
and  sacral  veins  in  the  loins  and  pelvis,  by  means  of  communicating 
trunks,  which  escape  at  the  intervertebral  foramina. 

The  Medulli-spinal  veins  are  situated  between  the  pia  mater  and 
arachnoid ;  they  communicate  freely  with  each  other,  and  form 
plexuses,  and  send  branches  through  the  intervertebral  foramina  with 
each  of  the  spinal  nerves,  to  join  the  veins  of  the  trunk. 

CARDIAC    VEINS. 

The  veins  returning  the  blood  from  the  substance  of  the  heart, 
are  the — 

Great  cardiac  vein, 
Posterior  cardiac  veins, 
Anterior  cardiac  veins, 
Venee  Thebesii. 

The  Great  cardiac  vein  (coronary)  commences  at  the  apex  of  the 
heart,  and  ascends  along  the  anterior  ventricular  groove  to  the  base 
of  the  ventricles;  it  then  curves  around  the  left  auriculo-ventricular 
groove  to  the  posterior  part  of  the  heart,  where  it  terminates  in  the 


PORTAL  SYSTEM.  369 

right  auricle.  It  receives  in  its  course  the  left  cardiac  veins  from 
the  left  auricle  and  ventricle,  and  the  posterior  cardiac  veins  from 
the  posterior  ventricular  groove. 

The  Posterior  cardiac  vein,  frequently  tw^o  in  number,  commences 
also  at  the  apex  of  the  heart,  and  ascends  along  the  posterior  ven- 
tricular groove,  to  terminate  in  the  great  cardiac  vein.  It  receives 
the  veins  from  the  posterior  aspect  of  the  two  ventricles. 

The  Anterior  cardiac  veins  collect  the  blood  from  the  anterior 
surface  of  the  right  ventricle ;  one  larger  than  the  rest  runs  along 
the  right  border  of  the  heart  and  joins  the  trunk  formed  by  these 
veins,  which  curves  around  the  right  auriculo-ventricular  groove,  to 
terminate  in  the  great  cardiac  vein  near  to  its  entrance  into  the 
right  auricle. 

The  VencB  Thehesii  are  numerous  minute  venules  which  convey 
the  venous  blood  directly  from  the  substance  of  the  heart  into  its 
four  cavities.     Their  existence  is  denied  by  some  anatomists. 

PORTAL     SYSTEM. 

The  portal  system  is  composed  of  four  large  veins  which  return 
the  blood  from  the  chylopoietic  viscera ;  they  are  the — 

Inferior  mesenteric  vein, 
Superior  mesenteric  vein, 
Splenic  vein, 
Gastric  veins. 

The  Inferior  mesenteric  vein  receives  its  blood  from  the  rectum  by 
means  of  the  hsemorrhoidal  veins,  and  from  the  sigmoid  flexure  and 
descending  colon,  and  ascends  beneath  the  transverse  duodenum  and 
pancreas,  to  terminate  in  the  splenic  vein.  Its  hsemorrhoidal 
branches  inosculate  with  the  branches  of  the  internal  iliac  vein, 
and  thus  establish  a  communication  between  the  portal  and  general 
venous  system. 

The  Superior  mesenteric  vein  is  formed  by  branches  which  col- 
lect the  venous  blood  from  the  capillaries  of  the  superior  mesenteric 
artery ;  they  constitute  by  their  junction  a  large  trunk  which 
ascends  by  the  side  of  the  corresponding  artery,  crosses  the  trans- 
verse duodenum,  and  unites  behind  the  pancreas  with  the  splenic  in 
the  formation  of  the  portal  vein. 

The  Splenic  vein  commences  in  the  structure  of  the  spleen,  and 
quits  that  organ  by  several  large  veins ;  it  is  larger  than  the  splenic 
artery,  and  perfectly  straight  in  its  course.  It  passes  horizontally 
inwards  behind  the  pancreas,  and  terminates  near  its  greater  end 
by  uniting  with  the  superior  mesenteric  and  forming  the  portal 
vein.  It  receives  in  its  course  the  gastric  and  pancreatic  veins,  and 
near  its  termination  the  inferior  mesenteric  vein. 

The  Gastric  veins  correspond  with  the  gastric,  gastro-epiploic, 
and  vasa  brevia  arteries,  and  terminate  in  the  splenic  vein. 

The  Vena  Port^,  formed  by  the  union  of  the  splenic  and  supe- 


370 


PULMONAEY  VEINS. 


rior  mesenteric  vein  behind  the  pancreas,  ascends  through  the  right 
border  of  the  lesser  omentum  to  the  transverse  fissure  of  the  hver, 
where  it  divides  into  two  branches,  one  for  each  lateral  lobe.  In 
the  right  border  of  the  lesser  omentum  it  is  situated  behind  and  be- 
tween the  hepatic  artery  and  ductus  communis  choledochus,  and  is 

Fig.  138, 


surrounded  by  the  hepatic  plexus  of  nerves  and  lymphatics.  At  the 
transverse  fissure  each  primary  branch  divides  into  numerous 
secondary  branches,  which  ramify  through  the  portal  canals,  and 
give  off  vaginal  and  interlobular  veins,  which  terminate  in  the 
lobular  venous  plexus  of  the  lobules  of  the  liver.  The  portal  vein 
within  the  liver  receives  the  venous  blood  from  the  capillaries  of  the 
hepatic  artery. 

PULMONARYVEINS. 

The  pulmonary  veins,  four  in  number,  return  the  arterial  blood 
from  the  lungs  to  the  left  auricle  of  the  heart ;  they  differ  from  the 

Fig.  138.  The  portal  vein.  1.  The  inferior  mesenteric  vein  :  it  is  traced  by  means 
of  dotted  lines  behind  the  pancreas  (2)  to  terminate  in  the  splenic  vein  (3),  4.  The 
spleen.  5.  Gastric  veins,  opening  into  the  splenic  vein.  6.  The  superior  mesenteric 
vein.  7.  The  descending  portion  of  the  duodenum.  8.  Its  transverse  portion,  which 
is  crossed  by  the  superior  mesenteric  vein  and  by  a  part  of  the  trunk  of  the  superior 
mesenteric  artery.  9.  The  portal  vein.  10.  The  iicpatic  artery.  11.  The  ductus 
communis  choledochus.  12.  Tlie  divisions  of  the  duet  and  vessels  at  the  transverse 
fissure  of  the  liver.     J3.  The  cystic  duel  leading  to  tlie  gall-bladder. 


PULMONARY  VEINS.  371 

veins  in  general,  in  the  area  of  their  cylinders  being  very  little 
larger  than  the  corresponding  arteries,  and  in  accompanying  singly 
each  branch  of  the  pulmonary  artery.  They  commence  in  the 
capillaries  upon  the  parietes  of  the  bronchial  cells,  and  unite  to 
form  a  single  trunk  for  each  lobe.  The  vein  of  the  middle  lobe  of 
the  right  lung  unites  vv^ith  the  superior  vein  so  as  to  form  the  two 
trunks  which  open  into  the  left  auricle.  Sometimes  they  remain 
separate,  and  then  there  are  three  pulmonary  veins  on  the  right 
side.  The  right  pulmonary  veins  pass  behind  the  superior  vena 
cava  to  the  left  auricle,  and  the  left  behind  the  pulmonary  artery  ; 
they  both  pierce  the  pericardium.  Within  the  lung  the  branches  of 
the  pulmonary  veins  are  behind  the  bronchial  tubes,  and  those  of 
the  pulmonary  artery  in  front ;  but  at  the  root  of  the  lungs  the 
veins  are  in  front,  next  the  arteries,  and  then  the  bronchi.  There 
are  no  valves  in  the  pulmonary  veins. 


r 


CHAPTER    VII. 

ON  THE  LYMPHATICS. 

The  lymphatic  vessels,  or  absorbents,  have  received  their  double 
appellation  from  certain  phenomena  which  they  present ;  the  former 
name  is  derivable  from  the  peculiar  limpid  fluid  (lympha,  water,) 
which  they  convey;  and  the  latter,  from  their  supposed  property  of 
absorbing  foreign  substances  into  the  system.  They  are  minute  and 
delicate  vessels,  having  a  knotted  appearance,  and  are  distributed 
through  every  part  of  the  body.  Their  office  is  to  collect  the  pro- 
ducts of  digestion,  and  the  detrita  of  nutrition,  and  to  convey  them 
into  the  venous  circulation  near  to  the  heart. 

Lymphatic  vessels  commence  in  a  delicate  network  which  is  dis- 
tributed upon  the  cutaneous  surface  of  the  body,  upon  the  various 
surfaces  of  organs  and  throughout  their  internal  structure ;  and 
from  this  network  the  lymphatic  vessels  proceed,  nearly  in  straight 
lines,  in  a  direction  towards  the  root  of  the  neck.  In  their  course 
they  are  intercepted  by  numerous  small  oval  or  rounded  bodies — 
lymphatic  glands — in  which  the  entering  or  inferent  vessels  ramify 
to  an  extreme  minuteness,  and  from  which  proceed  the  escaping  or 
efferent  vessels  somewhat  larger  in  size  and  fewer  in  number,  to  be 
again  and  again  subdivided  into  other  glands,  and  each  time  to  be 
a  little  more  increased  in  size. 

Lymphatic  vessels  admit  of  a  threefold  division  into  superficial, 
deep,  and  lacteals.  The  superficial  lymphatic  vessels,  upon  the  sur- 
face of  the  body,  follow  the  course  of  the  veins,  and  pierce  the  deep 
fascia  in  convenient  situations,  to  join  the  deep  lymphatics.  Upon 
the  surface  of  organs  they  converge  to  the  nearest  lymphatic  trunks. 

The  Superficial  lymphatic  glands  are  placed  in  the  most  protected 
situations  of  the  superficial  fascia,  as  in  the  hollow  of  the  ham  and 
groin  in  the  lower  extremity,  and  upon  the  inner  side  of  the  arm  in 
the  upper  extremity.  The  deep  lymphatics  accompany  the  deeper 
veins ;  those  from  the  lower  parts  of  the  body  converging  to  the 
numerous  glands  seated  around  the  iliac  veins  and  inferior  vena 
cava,  and  terminating  in  a  large  trunk  situated  upon  the  vertebral 
column — the  thoracic  duct.  From  the  upper  part  of  the  trunk  on 
the  left  side,  and  from  the  left  side  of  the  head  and  neck,  they  also 
proceed  to  the  thoracic  duct.  Those  on  the  right  side  of  the  head, 
and  neck,  right  upper  extremity,  and  right  side  of  the  thorax,  form 
a  distinct  duct  which  terminates  at  the  point  of  junction  of  the  sub- 
clavian with  the  internal  jugular  vein  on  the  right  side  of  the  root 
of  the  neck. 


LYMPHATICS  OF  THE  HEAD  AND  NECK.  373 

The  lacteals  are  the  lymphatics  of  the  small  intestines ;  they 
have  received  their  distinctive  appellation  from  conveying  the  milk- 
like product  of  digestion — the  chyle — to  the  great  centre  of  the 
lymphatic  system — the  thoracic  dnct.  They  are  situated  in  the 
mesentery,  and  pass  through  the  numerous  mesenteric  glands  in 
their  course. 

The  communications  between  lymphatic  vessels  are  less  frequent 
than  those  of  arteries  or  veins ;  their  anastomoses  take  place  by 
means  of  branches  of  equal  calibre  that  unite  at  acute  angles,  and 
constitute  a  combined  trunk,  which  is  scarcely  larger  than  either  of 
the  single  branches  by  which  it  is  formed. 

Lymphatic  vessels  are  composed  of  two  coats;  an  external  or 
cellular,  and  an  internal  or  serous. 

The  External  coat  resembles  the  external  tunic  of  veins  and  arte- 
ries, but  is  extremely  thin  and  dense.  The  Internal  coat  is  con- 
tinuous with  the  internal  lining  of  the  veins ;  and,  like  that  mem- 
brane, is  most  probably  provided  with  an  epithelium.  At  short 
intervals  this  coat  forms  semilunar  folds  which  are  disposed  in 
pairs  in  the  cylinder  of  the  vessel  and  constitute  the  valves.  It  is 
to  these  valves,  which  are  extremely  numerous  in  lymphatics,  that 
their  peculiar  knotted  appearance  is  due,  when  filled  with  injection. 

The  lymphatic  glands  are  small  oval  and  somewhat  flattened  oi' 
rounded  bodies,  composed  of  a  plexus  of  minute  lymphatic  vessels, 
associated  with  a  plexus  of  blood-vessels,  and  enclosed  in  a  thin 
cellular  capsule.  The  larger  glands  have  a  lobed  or  cellular 
appearance.  The  lymphatic  vessels  and  glands  are  supplied  with 
arteries,  veins,  and  nerves,  like  other  structures. 

I  shall  describe  the  lymphatic  vessels  and  glands  according  to 
the  arrangement  adopted  for  the  veins,  commencing  with  those  of 
the  head  and  neck,  and  proceeding  next  to  those  of  the  upper 
extremity,  lower  extremity,  and  trunk. 

LYMPHATICS  OF  THE  HEAD  AND  NECK. 

The  Superficial  lymphatic  glands  of  the  head  and  face  are  small 
and  few  in  number ;  they  are  the  occipital,  which  are  situated  near 
the  origin  of  the  occipito-frontalis  muscle;  posterior  auricular, 
behind  the  ear;  parotid,  in  the  parotid  gland;  zygomatic,  in  the 
zygomatic  fossa ;  buccal,  upon  the  buccinator  muscle  ;  and  sub- 
maxillary, beneath  the  margin  of  the  lower  jaw.  There  are  no 
deep  lymphatic  glands  within  the  cranium. 

The  Superficial  cervical  lymphatic  glands  are  few  in  number  ; 
they  are  situated  in  the  course  of  the  external  jugular  vein,  between 
the  sterno-mastoid  and  trapezius  muscles,  at  the  root  of  the  neck 
and  about  the  larynx. 

The  Deep  cervical  glands  are  very  numerous  and  of  large  size; 
they  are  situated  around  the  internal  jugular  vein  and  sheath  of  the 
arteries,  by  the  side  of  the  pharynx,  oesophagus,  and  trachea,  and 
extend  from  the  base  of  the  skull  to  the  root  of  the  neck,  where 

32 


374  LYMPHATICS  OF  THE  UPrER  EXTREMITY. 

they  are  in  communication  with  the  lymphatic  vessels  and  glands 
of  ihe  thorax. 

.  The  Superficial  lymphatic  vessels  of  the  head  and  face  are  disposed 
in  three  groups ;  occipital,  which  take  the  course  of  the  occipital 
vein  to  the  occipital  and  deep  cervical  glands ;  temporal,  which  fol- 
low the  branches  of  the  temporal  vein  to  the  parotid  and  deep  cer- 
vical glands  ;  and  facial,  which  accompany  the  facial  vein  to  the 
submaxillary  lymphatic  glands. 

The  Deep  lymphatic  vessels  of  the  head  are  the  meningeal  and 
cerebral ;  the  former  are  situated  in  connexion  with  the  meningeal 
veins,  and  escape  through  foramina  at  the  base  of  the  skull,  to  join 
the  deep  cervical  glands.  The  cerebral  lymphatics,  according  to 
Fohmann,  are  situated  upon  the  surface  of  the  pia  mater.  They 
pass  most  probably  through  the  foramina  at  the  base  of  the  skull,  to 
terminate  in  the  deep  cervical  glands. 

The  Deep  lymphatic  vessels  of  the  face  proceed  from  the  nasal 
fossiB,  mouth,  and  pharynx,  and  terminate  in  the  submaxillary  and 
deep  cervical  glands. 

The  Superficial  and  deep  cervical  lymphatic  vesse/s,  accompany  the 
jugular  veins,  passing  from  gland  to  gland,  and  at  the  root  of  the 
neck  communicate  with  the  thoracic  lymphatic  vessels,  and  termi- 
nate, on  the  right  side,  in  the  ductus  lymphaticus  dexter,  and,  on  the 
left,  in  the  thoracic  duct,  near  to  its  termination. 

LYMPHATICS    OP     THE     UPPER     EXTREMITY. 

The  Superficial  lymphatic  glands  of  the  arm  are  not  more  than 
four  or  five  in  number,  and  of  very  small  size.  One  or  two  are 
situated  near  the  median  basilic,  and  cephalic  veins,  at  the  bend  of 
the  elbow  ;  and  one  or  two  near  to  the  basilic  vein,  on  the  inner  side 
of  the  upper  arm,  immediately  above  the  elbow. 

The  Deep  glands  in  the  fore-arm  are  excessively  small  and  infre- 
quent; two  or  three  may  generally  be  found  in  the  course  of  the 
radial  and  ulnar  vessels.  In  the  upper  arm  there  is  a  chain  of  small 
glands,  accompanying  the  brachial  artery. 

The  Axillary  glands  are  numerous  and  of  large  size.  Some  are 
closely  adherent  to  the  vessels,  others  are  dispersed  in  the  loose  cel- 
lular tissue  of  the  axilla,  and  a  small  chain  may  be  observed  extend- 
ing along  the  lower  border  of  the  pectoralis  major  to  the  mammary 
gland.  Two  or  three  subclavian  glands,  are  situated  beneath  the 
clavicle,  and  serve  as  the  medium  of  communication  between  the 
axillary  and  deep  cervical  lymphatic  glands. 

The  Superficiallymphatic  vessels  of  the  upper  extremity  commence 
at  the  extremities  of  the  fingers,  and  pass  along  the  borders  of  the 
fingers  to  the  dorsum  of  the  hand  ;  they  next  ascend  the  fore-arm, 
some  on  its  posterior  and  some  on  its  anterior  aspect,  observing 
particularly  the  direction  of  the  veins.  At  the  bend  of  the  elbow 
they  converge,  to  form  two  groups  which  accompany  the  basilic 
and  cephalic  veins.    The  lymphatics  of  the  basilic  group  communi- 


LrMPHATICS  OF  THE  LOWER  EXTREMITY.  375 

cate  with  the  glands  situated  immediately  above  the  elbow,  and 
ascend  to  join  the  axillary  gland.  Those  of  the  cephalic  group  for 
the  most  part  cross  the  upper  part  of  the  biceps  muscle,  and  also 
enter  the  axillary  glands,  while  two  or  three  are  continued  onwards 
along  the  cephalic  vein,  in  ihe  interspace  between  the  pectoralis 
major  and  deltoid  muscle,  to  communicate  with  the  subclavian 
glands. 

The  Deep  lymphatics  accompany  the  vessels  of  the  upper  extre- 
mity, and  communicate  occasionally  with  the  superficial  lymphatics. 

They  enter  the  axillary  and  subclavian  glands,  and  at  the  root  of 
the  neck  terminate  on  the  left  side  in  the  thoracic  duct,  and  on  the 
right  side  in  the  ductus  lymphaticus  dexter. 

LYMPHATICS     OF     THE     LOWER     EXTREMITY. 

The  Superficial  lymphatic  glands  of  the  lower  extremity  are  those 
of  the  groin,  the  inguinal,  and  one  or  two  situated  in  the  superficial 
fascia  of  the  posterior  aspect  of  the  thigh,  just  above  the  popliteal 
region. 

The  Inguinal  glands  are  divisible  into  two  groups,  a  superior 
group  of  small  size,  situated  along  the  course  of  Poupart's  ligament, 
and  receiving  the  lymphatic  vessels  from  the  parietes  of  the  abdo- 
men and  genital  organs;  and  an  inferior  group  of  larger  glands 
clustered  around  the  internal  saphenous  vein  nea,r  to  its  termination, 
and  receiving  the  superficial  lymphatic  vessels  from  the  lower  ex- 
tremity. 

The  Deep  lymphatic  glands  are  the  anterior  tibial,  popliteal,  deep 
inguinal,  gluteal,  and  ischiatic. 

The  interior  tibial  is  generally  a  single  gland,  placed  on  the  in- 
terosseous membrane,  by  the  side  of  the  anterior  tibial  artery  in  the 
upper  part  of  its  course. 

The  Popliteal  glands,  four  or  five  in  number,  are  embedded  in  the 
loose  cellular  tissue  and  fat  of  the  popliteal  space. 

The  Deep  inguinal  glands,  less  numerous  and  smaller  than  the 
superficial,  are  situated  near  the  femoral  vessels  in  the  groin,  beneath 
the  fascia  lata. 

The  Gluteal  and  ischiatic  glands  are  placed  above  and  below  the 
pyriformis  muscle  at  the  great  ischiatic  foramen. 

The  Superficial  lymphatic  vessels  are  divisible  into  two  groups, 
internal  and  external ;  the  internal  and  principal  group  commencing 
on  the  dorsum  and  inner  side  of  the  foot,  ascend  the  leg  by  the  side 
of  the  internal  saphenous  vein,  and  passing  behind  the  inner  condyle 
of  the  femur,  follow  the  direction  of  that  vein  to  thcgroin,  where 
they  join  the  saphenous  group  of  superficial  inguinal  glands.  The 
greater  part  of  the  efTerent  vessels  from  these  glands  pierce  the 
cribriform  fascia  of  the  saphenous  opening  and  the  sheath  of  the 
femoral  vessels,  to  join  the  lymphatic  gland  situated  in  the  femoral 
ring,  which  serves  to  establish  a  communication  between  the  lym- 
phatics of  the  lower  extremity  and  those  of  the  trunk.     The  other 


376  LYMPHATICS  OF  THE  TRUNK. 

efferent  vessels  pierce  the  fascia  lata  to  join  the  deep  glands.  The 
vessels  which  pass  upwards  from  the  outer  side  of  the  dorsum  of  the 
foot,  ascend  upon  the  outer  side  of  the  leg,  and  curve  inwards  just 
below  the  knee,  to  unite  with  the  lymphatics  of  the  inner  side  of  the 
thigh.  The  external grouf  consists  of  a  few  lymphatic  vessels  which 
commence  upon  the  outer  side  of  the  foot  and  posterior  part  of  the 
ankle,  and  accompany  the  external  saphenous  vein  to  the  popliteal 
region,  where  they  enter  the  popliteal  glands. 

The  Deep  lymphatic  vessels  accompany  the  deep  veins,  and  com- 
municate with  the  various  glands  in  their  course.  After  joining  the 
deep  inguinal  glands  they  pass  beneath  Poupart's  ligament,  to  com- 
municate with  the  numerous  glands  situated  around  the  iliac  vessels. 
The  deep  lymphatics  of  the  gluteal  region  follow  the  course  of  the 
branches  of  the  gluteal  and  ischiatic  arteries.  The  former  join  the 
glands  situated  upon  the  upper  border  of  the  pyriformis  muscle,  and 
the  latter,  after  communicating  with  the  lymphatics  of  the  thigh, 
enter  the  ischiatic  glands. 

LYMPHATICS    OF     THE     TRUNK. 

The  lymphatics  of  the  trunk  may  be  arranged  under  three  heads, 
superficial,  deep,  and  visceral. 

The  Superficial  lymphatic  vessels  of  the  upper  half  of  the  trunk 
pass  upwards  and  outwards  on  each  side,  and  converge,  some  to  the 
axillary  glands,  and  the  others  to  the  glands  at  the  root  of  the  neck. 
The  lymphatics  from  the  mammary  glands  follow  the  lower  border 
of  the  pectoralis  major,  communicating  by  means  of  a  chain  of 
lymphatic  glands,  with  the  axillary  glands.  The  superficial  lymph- 
atic vessels  of  the  lower  half  of  the  trunk,  of  the  gluteal  region, 
perineum,  and  external  organs  of  generation,  converge  to  the  supe- 
rior group  of  superficial  inguinal  glands.  Some  small  glands  are 
situated  on  each  side  of  the  dorsal  vein  of  the  penis,  near  to  the 
suspensory  ligament ;  from  these,  as  from  the  superficial  lymphatics, 
the  efferent  vessels  pass  into  the  superior  group  of  superficial  inguinal 
glands. 

The  Deep  lymphatic  glands  of  the  thorax  are  the  intercostal,  in- 
ternal mammary,  anterior  mediastinal,  and  posterior  mediastinal. 

The  Intercostal  glands  are  of  small  size,  and  are  situated  on  each 
side  of  the  vertebral  column,  near  to  the  articulations  of  the  heads 
of  the  ribs,  and  in  the  course  of  the  intercostal  arteries. 

The  Internal  mammary  glands,  also  very  small,  are  placed  in  the 
intercostal  spaces,  by  the  side  of  the  internal  mammary  arteries. 

The  Anterior  mediastinal  glands  occupy  the  loose  cellular  tissue 
of  the  anterior  mediastinum,  resting  some  on  the  diaphragm,  but  the 
grenter  number  upon  the  large  vessels  at  the  root  of  the  heart. 

The  Posterior  mediastinal  glands  are  situated  along  the  course  of 
the  aorta  and  ccsophagus  in  the  posterior  mediastinum,  and  com- 
municate above  with  the  deep  cervical  glands,  on  each  side  with 
the  intercostal,  and  below  with  the  abdominal  glands. 


LYMPHATICS  OF  THE  VISCERA.  377 

The  Deep  lymphatic  vessels  of  the  thorax  are  the  intercostal,  in- 
ternal mammar}',  and  diaphragmatic. 

The  Intercostal  lymphatic  vessels  follow  the  courseof  the  arteries 
of  the  same  name;  and  reaching  the  vertebral  column  curve  down- 
wards, to  terminate  in  the  thoracic  duct. 

The  Internal  mammary  lymphatics  commence  in  the  parietes  of 
the  abdomen,  communicating  with  the  epigastric  lymphatics.  They 
ascend  by  the  side  of  the  internal  mammary  vessels,  being  joined  in 
their  course  by  the  anterior  intercostals,  and  terminate  on  the  right 
side  in  the  tributaries  of  the  ductus  lymphaticus  dexter ;  and  on  the 
left  side  in  the  thoracic  duct.  The  diaphragmatic  lymphatics  pur- 
sue the  direction  of  their  corresponding  veins,  and  terminate,  some 
in  front  in  the  internal  mammary  vessels,  and  some  behind,  in  the 
posterior  mediastinal  lymphatics. 

The  Deep  lymphatic  glands  of  the  abdomen  are  the  lumbar  glands; 
they  are  very  numerous,  and  are  seated  around  the  common  iliac 
vessels,  the  aorta  and  vena  cava. 

The  deep  lymphatic  glands  of  the  pelvis  are  the  external  iliac, 
internal  iliac,  and  sacral. 

The  External  iliac  are  placed  around  the  external  iliac  vessels, 
being  in  continuation  by  one  extremity  with  the  femoral  lymphatics, 
and  by  the  other  with  the  lumbar  glands. 

The  Internal  iliac  glands  are  situated  in  the  course  of  the  internal 
iliac  vessels,  and  the  sacral  glands  are  supported  by  the  concave 
surface  of  the  sacrum. 

The  Deep  lymphatic  vessels  are  continued  upwards  from  the  thigh, 
beneath  Poupart's  ligament,  and  along  the  external  iliac  vessels  to 
the  lumbar  glands,  receiving  in  their  course  the  epigastric,  circum- 
flex ilii,  and  ilio-lumbar  lymphatic  vessels.  Those  from  the  parietes 
of  the  pelvis,  and  from  the  gluteal,  ischiatic,  and  obturator  vessels, 
follow  the  course  of  the  internal  iliac  arteries,  and  unite  with  the 
lumbar  lymphatics.  And  the  lumbar  lymphatic  vessels,  after  re- 
ceiving all  the  lymphatics  from  the  lower  extremities,  pelvis,  and 
loins,  terminate  by  several  large  trunks  in  the  receptaculum  chyli. 

LYMPHATICS     OF     THE     VISCERA. 

The  Lymphatic  vessels  of  the  lungs  are  distributed  over  every 
part  of  the  surface,  and  through  the  texture  of  these  organs ;  they 
converge  to  the  numerous  glands  situated  around  the  bifurcation  of 
the  trachea  and  roots  of  the  lungs — the  bronchial  glands.  Some  of 
these  glands  of  small  size,  may  be  traced  in  connexion  with  the 
bronchial  tubes  for  some  distance  into  the  lungs.  The  efferent 
vessels  from  the  bronchial  glands  unite  with  the  tracheal  and  oeso- 
phageal glands,  and  terminate  principally  in  the  thoracic  duct  at 
the  root  of  the  neck,  and  partly  in  the  ductus  lymphaticus  dexter. 
The  bronchial  glands,  in  the  adult,  present  a  variable  tint  of  brown, 
and  in  old  age  a  deep  black  colour.  In  infancy  they  have  none  of 
this  pigment,  and  are  not  to  be  distinguished  from  lymphatic  glands 
in  other  situations. 

32* 


378  LYMPHATICS  OF  THE  LIVER. 

The  Lijmphalic  vessels  of  the  heart  originate  in  the  subserous  cel- 
lular tissue  of  the  surface,  and  in  the  deeper  tissues  of  the  organ, 
and  follow  the  course  of  the  vessels,  principally,  along  the  right 
border  of  the  heart  to  the  glands  situated  around  the  arch  of  the 
aorta  and  bronchial  glands,  whence  they  proceed  to  the  thoracic 
duct. 

The  Pericardiac  and  thymic  lymphatic  vessels  proceed  to  join  the 
anterior  mediastinal  and  bronchial  glands. 

The  Lymphatic  vessels  of  the  liver  are  divisible  into  the  deep  and 
superficial.  The  former  take  their  course  through  the  portal  canals, 
and  through  the  right  border  of  the  lesser  omentum,  to  the  lymphatic 
glands,  situated  in  the  course  of  the  hepatic  artery  and  along  the 
lesser  curve  of  the  stomach.  The  superficial  lymphatics  are  situated 
in  the  cellular  structure  of  the  proper  capsule,  over  the  whole  sur- 
face of  the  liver.  Those  of  the  convex  surface  are  divided  into  two 
sets  : — 1.  Those  which  pass  from  before  backwards.  2.  Those 
which  advance  from  behind  forwards.  The  former  unite  to  form 
trunks,  which  enter  between  ihe  folds  of  the  lateral  ligaments  at  the 
right  and  left  extremities  of  the  organ,  and  of  the  coronary  ligament 
in  the  middle.  Some  of  these  pierce  the  diaphragm  and  join  the 
posterior  mediastinal  glands ;  others  converge  to  the  lymphatic 
glands  situated  around  the  inferior  cava.  Those  which  pass  from 
behind  forwards  consist  of  two  groups :  one  ascends  between  the 
folds  of  the  broad  ligament,  and  perforates  the  diaphragm,  to  ter- 
minate in  the  anterior  mediastinal  glands  ;  the  other  curves  around 
the  anterior  margin  of  the  liver  to  its  concave  surface,  and  from 
thence  to  the  glands  in  the  right  border  of  the  lesser  omentum.  The 
lymphatic  vessels  of  the  concave  surface  are  variously  distributed, 
according  to  their  position  :  those  from  the  right  lobe  terminate  in 
the  lumbar  glands  ;  those  from  the  gall-bladder,  which  are  large  and 
form  a  remarkable  plexus,  enter  the  glands  in  the  right  border  of 
the  lesser  omentum  ;  and  those  from  the  left  lobe  converge  to  the 
lymphatic  glands,  situated  along  the  lesser  curve  of  the  stomach. 

The  Lymphatic  glands  of  the  spleen  are  situated  around  its  hilus, 
and  those  of  the  pancreas  in  the  course  of  the  splenic  vein.  The 
Iy)nphatic  vessels  of  these  organs  pass  through  their  respective  glands, 
and  join  the  aortic  glands,  previously  to  terminating  in  the  thoracic 
duct. 

The  Lymphatic  glands  of  the  stomach  are  of  small  size,  and  are 
situated  along  the  lesser  and  greater  curves  of  that  organ.  The 
lymphatic  vessels,  as  in  other  viscera,  are  superficial  and  deep,  the 
former  originating  in  the  subserous  and  the  latter  in  the  submucous 
tissue;  they  pass  from  the  stomach  in  four  different  directions  ;  some 
ascend  to  the  glands  situated  along  the  lesser  curve, — others  descend 
lo  those  occupying  the  greater  curve, — a  third  set  passes  outwards 
to  the  splenic  glands,  and  a  fourth  to  the  glands  situated  near  the 
pylorus  and  to  the  aortic  glands. 

The  Lymphatic  glands  of  the  small  intestine  are  situated  between 
the  layers  of  the  mesentery,  in  the  meshes  formed  by  the  superior 


THORACIC  DUCT.  379 

mesenteric  artery,  and  thence  named  mesenteric  glands.  These 
glands  are  most  numerous  and  largest,  superiorly,  near  to  the 
duodenum  ;  and,  inferiorly,  near  to  the  termination  of  the  ileum. 

The  Lymphatic  vessels  of  the  small  intestine  are  of  two  kinds  : 
those  of  the  structure  of  the  intestine,  which  ramify  upon  its  sur- 
face previously  to  entering  the  mesenteric  glands;  and  those  which 
commence  in  the  villi,  upon  the  surface  of  the  mucous  membrane, 
and  are  named  lacteals. 

The  Lacteals  according  to  the  most  recent  and  best  researches — 
those  of  Dr.  Henle  of  Berlin — commence  in  the  centre  of  each  villus 
as  a  coecal  tubulus,  which  opens  into  a  fine  network,  situated  in  the 
submucous  tissue.  From  this  areolar  network  the  lacteal  vessels 
proceed  to  the  mesenteric  glands,  and  from  thence  to  the  thoracic 
duct,  in  which  they  terminate. 

The  Lymphatic  glands  of  the  large  intestines  are  situated  along 
the  attached  margin  of  the  intestine,  in  the  meshes  formed  by  the 
arteries  previously  to  their  distribution.  The  lymphatic  vessels  take 
their  course  in  two  different  directions ;  those  of  the  coecum,  ascend- 
ing and  transverse  colon,  after  traversing  their  proper  glands,  pro- 
ceed to  the  mesenteric,  and  those  of  the  descending  colon  and  rectum 
to  the  lumbar  glands. 

The  Lymphatic  vessels  of  the  kidney  follow  the  direction  of  the 
blood-vessels  to  the  lumbar  ganglia  situated  around  the  aorta  and 
inferior  vena  cava :  those  of  the  supra-renal  capsules,  which  are 
very  large  and  numerous,  terminate  in  the  renal  lymphatics. 

The  Lymphatic  vessels  of  the  viscera  of  the  pelvis  terminate  in  the 
sacral  and  lumbar  ganglia. 

ThetLymphatic  vessels  of  the  testicle  take  the  course  of  the  sper- 
matic cord,  where  they  are  of  large  size,  as  is  shown  in  the  beautiful 
injections  made  by  Sir  Astley  Cooper  ;  they  terminate  in  the  lumbar 
ganglia. 

THORACIC     DUCT. 

The  thoracic  duct  commences  in  the  abdomen,  by  a  considerable 
and  somewhat  triangular  dilatation,  the  receptaculum  chyli,  which  is 
situated  upon  the  front  of  the  body  of  the  second  lumbar  vertebra, 
behind  and  between  the  aorta  and  inferior  vena  cava,  and  close  to 
the  tendon  of  the  right  crus  of  the  diaphragm.  From  the  upper 
part  of  the  receptaculum  chyli,  the  thoracic  duct  ascends  through 
the  aortic  opening  in  the  diaphragm,  and  along  the  front  of  the  ver- 
tebral column,  lying  between  the  thoracic  aorta  and  \iena  azygos,  to 
*  the  fourth  dorsal  vertebra.  It  then  inclines  to  the  left  side,  passes 
behind  the  arch  of  the  aorta,  and  ascends  by  the  side  of  the  oeso- 
phagus and  behind  the  perpendicular  portion  of  the  left  subclavian 
artery  to  the  root  of  the  neck  opposite  the  seventh  cervical  vertebra, 
where  it  makes  a  sudden  curve  forwards  and  downwards,  and  ter- 
minates at  the  point  of  junction  of  the  left  subclavian  with  the  left 
internal  jugular  vein. 


380 


THORACIC  DUCT. 


Fiff.  139. 


The  thoracic  duct  is  equal  in  size  to  the  diameter  of  a  goose- 
quill  at  its  commencement  from  the 
receptaculum  chyli,  diminishes  consi- 
derably in  diameter  towards  the  middle 
of  the  posterior  mediastinum,  and  again 
becomes  dilated  near  its  termination-  At 
about  the  middle  of  its  course  it  fre- 
quently divides  into  two  branches  of 
equal  size,  which  reunite  after  a  short 
course ;  and  sometimes  it  gives  off  se- 
veral branches,  which  assume  a  plexi- 
form  arrangement  in  this  situation.  Oc- 
casionally the  thoracic  duct  bifurcates 
at  the  upper  part  of  the  thorax  into  two 
branches,  one  of  which  opens  into  the 
point  of  junction  between  the  right  sub- 
clavian and  jugular  veins,  while  the 
other  proceeds  to  the  normal  termina- 
tion of  the  duct  on  the  left  side.  In  rare 
instances  the  duct  has  been  found  to 
terminate  in  the  vena  azygos,  which  is 
its  normal  destination  in  some  Mam- 
malia. 

The  thoracic  duct  presents  fewer 
valves  in  its  course  than  lymphatic 
vessels  generally ;  at  its  termination  it 
is  provided  with  a  pair  of  semilunar 
valves  which  prevent  the  admission  of 
^  venous  blood  into  its  cylinder. 

Branches. — The  thoracic  duct  re- 
ceives at  its  commencement  four  or 
five  large  lymphatic  trunks  which  unite 
to  form  the  receptaculum  chyli ;  it  next  receives  the  trunks  of  the 
lacteal  vessels.  Within  the  thorax  it  is  joined  by  a  large  lymphatic 
trunk  from  the  liver,  and  in  its  course  through  the  posterior  medias- 
tinum, receives  the  lymphatic  vessels  both  from  the  viscera  and 
from  the  parietes  of  the  thorax.     At  its  curve  forwards  in  the  neck 


Fig.  139.  The  course  and  termination  of  the  thoracic  duct.  1.  The  arch  of  the 
aorta.  2.  The  thoracic  aorta.  3.  The  abdominal  aorta;  showing  its  principal  branches 
divided  near  their  origin.  4.  The  arteria  innominata,  dividing  into  the  right  cjrotid 
and  right  subclavian  arteries.  5.  The  left  carotid.  6.  The  left  subclavian.  7.  The 
superior  cava,  fornfied  by  the  union  of  8,  the  two  vcnse  innominatsB  ;  and  these  by  the 
junction  9,  of  the  internal  jugular  and  subclavian  vein  at  each  side.  10.  The  greater 
vena  azygos.  11.  The  termination  of  the  lesser  in  the  greater  vena  azygos.  12.  The 
receptaculum  chyli ;  several  lymphatic  trunks  are  seen  opening  into  it.  13.  Tlie  tho- 
racic duct,  dividing  opposite  the  middle  of  the  dorsal  vertebra}  into  two  branches 
which  soon  reunite  ;  the  course  of  the  duct  behind  the  arch  of  the  aorta  and  left  sub- 
clavian artery  is  shown  by  a  dotted  line.  14.  The  duct  making  its  turn  at  the  root  of 
the  neck  and  receiving  several  lymphatic  trunks  previously  to  terminating  in  the  pos- 
terior aspect  of  tiic  junction  of  tiie  internal  jugular  and  subclavian  vein.  15.  The 
termination  of  the  trunk  of  the  ductus  lymphaticus  dexter. 


EIGHT  THORACIC  DUCT.  381 

it  is  joined  by  the  lymphatic  trunks  from  the  left  side  of  the  head 
and  neck,  left  upper  extremity,  and  from  the  upper  part  of  the 
thorax,  and  thoracic  viscera. 

The  Ductus  li/mphaticus  dexter  is  a  short  trunk  which  receives 
the  lymphatic  vessels  from  the  right  side  of  the  head  and  neck, 
right  upper  extremity  and  right  side  of  the  thorax,  and  terminates 
at  the  junction  of  the  right  subclavian  with  the  right  internal 
jugular  vein,  at  the  point  where  these  veins  unite  to  form  the  right 
vena  innominata.  It  is  provided  at  its  termination  with  a  pair 
of  semilunar  valves,  which  prevent  the  entrance  of  blood  from  the 
veins. 


CHAPTER  VIII. 


ON  THE  NERVOUS  SYSTEM. 


The  nervous  system  consists  of  a  central  organ,  the  cerebro- 
spinal centre  or  axis,  and  of  numerous  rounded  and  flattened  white 
cords, — the  nerves,  which  are  connected  by  one  extremity  with  the 
cerebro-spinal  centre,  and  by  the  other  are  distributed  to  all  the 
textures  of  the  body.  The  sympathetic  system  is  an  exception  to 
this  description;  for  in  place  of  one  it  has  many  small  centres, 
which  are  called  ganglia,  and  which  communicate  very  freely  with 
the  cerebro-spinal  axis  and  with  its  nerves. 

The  cerebro-spinal  axis  consists  of  two  portions,  the  brain,  an 
organ  of  large  size,  situated  within  the  skull,  and  the  spinal  cord,  a 
lengthened  portion  of  the  nervous  centre,  continuous  with  the  brain, 
and  occupying  the  canal  of  the  vertebral  column. 

The  most  superficial  examination  of  the  brain  and  spinal  cord 
shows  them  to  be  composed  of  fibres,  which  in  some  situations  are 
ranged  side  by  side  or  collected  into  bundles  of  fasciculi,  and  in 
other  situations  are  interlaced  at  various  angles  by  cross  fibres. 
The  fibres  are  connected  and  held  together  by  a  delicate  cellular 
web,  which  forms  the  bond  of  support  to  the  entire  organ.  It  is 
also  observed  that  the  cerebro-spinal  axis  presents  two  substances 
differing  from  each  other  in  density  and  colour ;  a  gray  or  cineri- 
tious  or  cortical  substance,  and  a  white  or  medullary  substance. 
The  gray  substance  forms  a  thin  lamella  over  the  entire  surface  of 
the  convolutions  of  the  cerebrum,  and  the  laminae  of  the  cerebellum : 
hence  it  has  been  named  cortical;  but  the  gray  substance  is  not 
confined  to  the  surface  of  the  brain,  as  this  term  would  imply, — it  is 
likewise  situated  in  the  centre  of  the  spinal  cord  its  entire  length, 
and  may  be  thence  traced  through  the  medulla  oblongata,  crura 
cerebri,  thalami  optici,  and  corpora  striata;  it  enters  also  into  the 
composition  of  the  lobus  perforatus,  tuber  cinereum,  commissura 
mollis,  pineal  gland,  and  corpus  rhomboideum. 

The  fibres  of  the  cerebro-spinal  axis  are  arranged  into  two  classes, 
diverghig  and  converging.  The  diverging  fibres  proceed  from  the 
medulla  oblongata,  and  diverge  to  every  part  of  the  surface  of  the 
brain;  while  the  converging  commence  upon  the  surface,  and  pro- 
ceed inwards  towards  the  centre  so  as  to  connect  the  diverging 
fibres  of  opposite  sides.  In  certain  parts  of  their  course  the  diverging 
fibres  are  separated  by  the  gray  substance,  and  increase  in  number 
so  as  to  form  a  body  of  considerable  size,  which  is  called  a  ganglion. 
The  position  and  mutual  relations  of  these  fibres  and  ganglia  may 


NERVOUS  SYSTEM — DEVEL0PE3IENT.  383 

be  best  explained  by  reference  to  the  mode  of  developement  of  the 
cerebro-spinal  axis  in  animals  and  in  man. 

The  centre  of  the  nervous  system  in  the  lowest  animals  possessed 
of  a  lengthened  axis,  presents  itself  in  the  form  of  a  double  cord. 
A  step  higher  in  the  animal  scale,  and  knots  or  ganglia  are 
developed  upon  one  extremity  of  this  cord  ;  such  is  the  most  rudi- 
mentary condition  of  the  brain  in  the  lowest  forms  of  vertebrata. 
In  the  lowest  fishes  the  anterior  extremity  of  the  double  cord  dis- 
plays a  succession  of  five  pairs  of  ganglia.  The  higher  fishes  and 
amphibia  appear  to  have  a  different  disposition  of  these  primitive 
ganglia.  The  first  two  have  become  fused  into  a  single  ganglion, 
and  then  follow  only  three  pairs  of  symmetrical  ganglia.  But  if  the 
larger  pair  be  unfolded  after  being  hardened  in  alcohol,  it  will  then 
be  seen  that  the  whole  number  of  ganglia  exists,  but  that  four  have 
become  concealed  by  a  thin  covering  that  has  spread  across  the;n. 
This  condition  of  the  brain  carries  us  upwards  in  the  animal 
scale  even  to  Mammalia ;  e.  g.,  in  the  dog  or  cat  we  find,  first  a 
single  ganglion,  the  cerebellum,  then  three  pairs  following  each 
other  in  succession ;  and  if  we  unfold  the  middle  pair,  we  shall  be 
at  once  convinced  that  it  is  indeed  composed  of  two  pairs  of  pri- 
mitive ganglia  concealed  by  an  additional  developement.  Again 
it  will  be  observed,  that  the  primitive  ganglia  of  opposite  sides,  at 
first  separate  and  disjoined,  become  connected  by  means  of  trans- 
verse fibres  of  communication  (commissures,  commissura,  o.  joining). 
The  oliice  of  these  commissures  is  the  association  in  function  of 
the  two  symmetrical  portions.  Hence  we  arrive  at  the  general  and 
important  conclusion,  that  the  brain  among  the  lower  animals  con- 
sists of  primitive  cords,  primitive  ganglia  upon  those  cords,  and 
commissures  which  connect  the  substances  of  the  adioinino;  ganglia, 
and  associate  their  functions. 

In  the  developement  of  the  cerebro-spinal  axis  in  man,  the  earliest 
indication  of  the  spinal  cord  is  presented  under  the  form  of  a  pair 
of  minute  longitudinal  filaments  placed  side  by  side.  Upon  these, 
towards  the  anterior  extremity,  five  pairs  of  minute  swellings  are 
observed,  not  disposed  in  a  straight  line  as  in  fishes,  but  curved 
upon  each  other  so  as  to  correspond  with  the  direction  of  the  future 
cranium.  The  posterior  pair  soon  becomes  cemented  upon  the 
middle  line,  forming  a  single  ganglion;  the  second  pair  also  unite 
with  each  other;  the  third  and  fourth  pairs,  at  first  distinct,  are 
speedily  veiled  by  a  lateral  developement,  which  arches  backwards 
and  conceals  them  ;  the  anterior  pairs,  at  first  very  small,  decrease 
in  size  and  become  almost  lost  in  the  increased  developement  of  the 
preceding  pairs. 

We  see  here  a  chain  of  resemblances  corresponding  with  the  pro- 
gressive developement  observed  in  the  lower  animals  ;  the  human 
brain  is  passing  through  the  phases  of  improving  developement, 
which  distinfTitish  the  higher  from  the  lower  creatures :  and  we  are 
naturally  led  to  the  same  conclusion  with  regard  to  the  architecture 
of  the  human  brain,  that  we  were  led  to  establish  as  the  principle 
of  developement  in  the  inferior  creature — that  it  is  composed  of 


384  NERVOUS  SYSTEM STRUCTURE. 

primitive  cords,  primitive  ganglia   upon  those  cords,  commissures 
to  connect  those  ganglia,  and  devehpemevts  from  those  ganglia. 

-In  the  adult,  the  primitive  longitudinal  cords  have  become  cement- 
ed together,  to  form  the  spinal  cord.  But,  at  the  upper  extremity, 
they  separate  from  each  other  under  the  name  of  crura  cerebri. 
The ^rs^  pair  of  ganglia  developed  from  the  primitive  cords,  have 
grown  into  the  cerebellum ;  the  second  pair  (the  optic  lobes  of 
animals)  have  become  the  corpora  quadrigemina  of  man.  The 
third  pair,  the  optic  thalami,  and  the  fourth,  the  corpora  striati,  are 
the  basis  of  the  hemispheres,  which,  the  merest  lamina  in  the  fish, 
has  become  the  largest  portion  of  the  brain  in  man.  And  the  fifth 
pair  (olfactory  lobes),  so  large  in  the  lowest  forms,  have  dwindled 
into  the  olfactory  bulbs  of  man. 

The  white  substance  of  the  brain  and  spinal  cord  when  examined 
with  the  microscope,  is  found  to  consist  of  fibres  varying  in  diameter, 
according  to  Krause,  from  the  -jy^^  to  the  rix  of  a  line.  These 
fibres  are  composed  of  a  thin  and  transparent  neurilemma,  en- 
closing a  soft  homogeneous  nervous  substance,  and  they  possess  a 
remarkable  tendency,  when  compressed,  to  assume  a  varicose  ap- 
pearance. The  nervous  fibres  of  the  olfactory,  optic,  and  auditory 
nerves  have  the  same  disposition  to  become  varicose  on  pressure. 
The  neurilemma  of  the  primitive  fibre,  according  to  Fontana,  con- 
sists of  two  layers,  of  which  the  internal  is  thin  and  transparent,  and 
the  external  cellular  and  less  transparent. 

The  gray  substance  of  the  brain,  according  to  Valentin,  is  com- 
posed of  spherical  globules  of  considerable  size,  having  a  central 
nucleus,  and  near  the  margin  of  the  latter  another  smaller  nucleus, 
and  frequently  upon  the  surface  of  the  globule,  patches  of  pigment. 
Numerous  minute  fibres  have  been  observed  by  Remak  to  proceed 
from  the  surface  of  these  globules,  and  are  supposed  to  maintain  a 
communication  with  surrounding  globules.  The  various  shades  of 
gray  observed  in  different  parts  of  the  brain  depend  upon  the 
greater  or  smaller  number  of  globules  existing  in  those  parts.  Two 
kinds  of  gray  substance  are  described  by  Rolanda  as  existing  in 
the  spinal  cord  ;  the  one  {substantia  cinerea  spongiosa  vasculosa)  is 
the  ordinary  gray  matter  of  the  cord,  and  the  other  {substantia 
cinerea  gelatinosa)  forms  part  of  the  posterior  cornua.  The  former 
resembles  the  gray  matter  of  the  brain,  consisting  of  globules,  while 
the  latter  is  composed  of  small  bodies  resembling  the  blood  corpus- 
cules  of  the  frog. 

The  nerves  are  divisible  into  two  great  classes, — those  which 
proceed  directly  from  the  cerebro-spinal  axis,  the  cranial  and  spinal 
nerves,  and  constitute  the  system  of  animal  life ;  and  those  which 
originate  from  a  system  of  nervous  centres,  independent  of  the 
cerebro-spinal  axis,  but  closely  associated  with  that  centre  by  nu- 
merous communications,  the  sympathetic  system,  or  system  of  or- 
ganic life. 

The  division  of  nerves  into  cranial  and  spinal  is  purely  arbitrary, 
and  depends  upon  the  circumstance  of  the  former  passing  through 


CLASSIFICATION  OF  NERVES.  385 

the  foramina  of  the  cranium,  and  the  latter  through  those  of  the 
vertebral  column.  With  respect  to  origin, — all  the  cranial  nerves, 
with  the  exception  of  the  first, — olfactory,  proceed  from  the  spinal 
cord,  or  from  its  immediate  continuation  into  the  brain.  The  spinal 
nerves  arise  by  two  roots ;  anterior,  which  proceeds  from  the 
anterior  segment  of  the  spinal  cord,  and  possesses  a  motor  function  ; 
and  'posterior,  which  is  connected  with  the  posterior  segment,  and 
bestows  the  faculty  of  sensation.  The  motor  nerves  of  the  cranium 
are  shown  by  dissection  to  be  continuous  with  the  motor  portion  of 
the  cord,  and  form  one  system  with  the  motor  roots  of  the  spinal 
cord  ;  while  the  nerves  of  sensation,  always  excepting  the  olfactory, 
are  in  like  manner  traced  to  the  posterior  segment  of  the  cord,  and 
form  part  of  the  system  of  sensation.  To  these  two  systems  a  third 
has  been  added  by  Sir  Charles  Bell, — the  respiratory  system, — 
which  consists  of  nerves  associated  in  the  function  of  respiration, 
and  arising  frorn  the  side  of  the  upper  part  of  the  spinal  cord  in 
one  continuous  line,  which  was  thence  named,  by  that  distinguished 
physiologist,  the  respiratory  tract.  The  microscope  has  succeeded 
in  making  no  structural  distinction  between  the  anterior  and  pos- 
terior roots  of  the  spinal  nerves;  but  the  latter  are  remarkable  from 
possessing  a  gangUon  near  to  their  attachment  with  the  cord.  This 
gangUon  is  observed  upon  the  posterior  roots  of  all  the  spinal  nerves, 
and  also  upon  the  corresponding  root  of  the  fifth  cranial  nerve,  which 
is  thence  considered  a  spinal  cranial  nerve.  Upon  others  of  the 
cranial  nerves  a  ganglion  is  found,  which  associates  them  in  their 
function  with  the  nerves  of  sensation,  and  establishes  an  analogy 
with  the  spinal  nerves. 

The  recent  researches  of  Mr.  Grainger  have  made  an  important 
addition  to  our  knowledge  of  the  mode  of  connexion  of  the  nerves 
with  the  spinal  cord  ;  he  has  shown  that  both  roots  of  the  spinal 
nerves,  as  well  as  most  of  the  cerebral,  divide  into  two  sets  of  fila- 
ments upon  entering  the  cord,  one  set  being  connected  to  the  gray 
substance,  while  the  other  is  continuous  with  the  white  or  fibrous 
part  of  the  cord.  The  former  he  considers  to  be  the  agents  of  the 
excito-motory  system  of  Dr.  Marshall  Hall ;  and  the  latter,  the 
communication  with  the  brain  and  the  medium  for  the  transmission 
of  sensation  and  volition.  He  has  not  been  able  to  trace  the  fibres 
which  enter  the  gray  substance  to  their  termination;  but  he  thinks 
it  probable  that  the  ultimate  filaments  of  the  posterior  root  join  those 
of  the  anterior  root;  or  in  the  word«  of  Dr.  Marshall  Hall's  system, 
that  the  incident  fibres  (sensitive)  are  continuous  with  the  reflex 
(motor). 

The  connexion  of  a  nerve  with  the  cerebro-spinal  axis  is  called, 
for  convenience  of  description,  its  origin  :  this  term  must  not,  how- 
ever, be  received  literally;  for  each  nerve  is  developed  in  the  pre- 
cise situation  which  it  occupies  in  the  body,  and  with  the  same 
relations  that  it  possesses  in  after  life.  Indeed,  we  not  unfrequently 
meet  with  instances  in  anencephalous  foetuses,  where  the  nerves  are 
beautifully  and  completely  formed,  while  the  brain  and  spinal  cord 

33 


386  NERVES STRUCTURE COMMUNICATIONS, 

are  wholly  wanting.  The  word  origin  must,  therefore,  be  consi- 
dered as  a  relic  of  the  darkness  of  preceding  ages,  when  the 
cerebro-spinal  axis  was  looked  upon  as  the  tree  from  which  the 
nerves  pushed  forth  as  bi'anches.  In  their  distribution  the  spinal 
nerves  ibr  the  most  part  follow  the  course  of  the  arteries,  particu- 
larly in  the  limbs,  where  they  lie  almost  constantly  to  the  outer  side 
and  superficially  to  the  vessels,  as  if  for  the  purpose  of  receiving 
the  first  intimation  of  danger,  and  of  communicating  it  lo  the 
muscles,  that  they  may  instantly  remove  the  arteries  from  im- 
pending injury. 

The  microscopic  examination  of  a  cerebro-spinal  nerve  shows  it 
to  be  composed  of  minute  fibres,  resembling  those  of  the  brain,  and 
consisting  of  a  neurilemma  enclosing  a  soft,  homogeneous  nervous 
substance.  The  chief  diflerence  between  the  fibres  of  the  nerves 
and  the  cerebral  fibres  is  a  somewhat  greater  opacity  and  more 
granular  appearance  of  the  contents  of  the  minute  cylinders  of  the 
tormer ;  a  greater  thickness  of  their  neurilemma,  and  an  indisposi- 
tion to  the  formation  of  varicose  enlargements  upon  compression. 
The  neurilemma  presents  the  same  two  layers  which  exist  in  the 
cerebral  fibres.  The  •primitive  jibres,  ov  filaments,  are  assembled 
into  small  bundles  and  enclosed  in  a  distinct  sheath,  constituting  a 
funiculus;  the  funiculi  are  collected  into  larger  bundles  or  fasciculi, 
and  a  single  fasciculus  or  a  number  of  fasciculi  connected  by  cel- 
lular tissue,  and  invested  by  a  membranous  sheath,  constitute  a 
nerve.  The  funiculi,  when  freshly  exposed,  present  a  peculiar  zig- 
zag line  across  their  cylinder,  which  is  most  probably  produced  by. 
the  arrangement  of  the  primitive  fibres,  or  possibly  by  some  con- 
dition of  the  neurilemma.  This  appearance  is  destroyed  by  making 
extension  upon  the  nerve. 

Communications  between  nerves  take  place  either  by  means  of 
the  funiculi  composing  a  single  nerve,  or  of  the  fasciculi  in  a  nervous 
plexus.  In  these  communications  there  is  no  fusion  of  nervous  sub- 
stance, the  cord  formed  by  any  two  funiculi  is  constantly  enlarged, 
and  corresponds  accurately  with  their  combined  bulk.  Microscopic 
examination  substantiates  this  observation,  and  shows  that  the  pri- 
mitive fibre  passes  unchanged  from  one  funiculus  to  the  other,  so 
that  the  primitive  fibre  is  single  and  uninterrupted  from  its  connex- 
ion with  the  cerebro-spinal  axis  to  its  terminal  distribution.  A 
nervous  plexus  consists  in  a  communication  between  the  fasciculi 
and  funiculi  composing  the  nerves,  which  are  associated  in  their 
supply  of  a  limb  or  of  a  certain  region  of  the  body.  During  this 
communication  there  is  an  interchange  of  funiculi,  and  with  the 
funiculi  an  interchange  of  fibres. 

The  Sympathetic  system  consists  of  numerous  ganglia,  of  commu- 
nicating branches  passing  between  the  ganglia,  of  others  passing 
between  the  ganglia  and  the  cerebro-spinal  axis,  and  of  branches  of 
distribution  which  are  remarkable  for  their  frequent  and  plexiform 
communications.  The  sympathetic  nerves  also  differ  from  other 
nerves  in  their  colour,  which  is  of  a  grayish  pearly  tint.   Examined 


BRAIN MEMBRANES.  387 

with  the  microscope  the  sympathetic  nerves  are  seen  to  be  composed 
of  an  admixtureof  gray  and  white  fibres;  the  white  fibres  belong  to 
the  cerebro-spinal  system :  the  gray  are  much  smaller  than  the 
white,  less  transparent,  and  the  neurilemma  is  less  easily  distinguish- 
able from  its  contents :  some  of  the  nerves  are  composed  of  gray 
fibres  only  without  any  admixture  of  white.  The  sympathetic 
ganglia  contain  the  globules  observed  in  the  gray  substance  of  the 
brain;  they  are  firmer  in  structure  and  enclosed  in  a  strong  in- 
vesting capsule.  The  fasciculi  of  fibres  entering  the  ganglion  be- 
come divided  and  form  a  plexus  around  the  globules ;  they  then 
converge  to  constitute  another  fasciculus,  by  which  they  quit  the 
ganglion. 

The  nervous  system  may  be  divided  for  convenience  of  descrip- 
tion into  1.  The  brain.  2.  The  spinal  cord.  3.  The  cranial  nerves. 
4.  The  spinal  nerves.     5.  The  sympathetic  system. 

THE     BRAIN. 

The  brain  is  a  collective  term,  which  signifies  those  parts  of  the 
nervous  system,  exclusive  of  the  nerves  themselves,  which  are  con- 
tained within  the  cranium  ;  they  are  the  cerebrum,  cerebellum,  and 
medulla  oblongata.  These  are  invested  and  protected  by  the  mem- 
branes of  the  brain,  and  the  whole  together  constitute  the  ence- 
phalon  (sv,  xscpaXri,  within  the  head.) 

MEMBRANES    OF     THE     ENCEPHALON. 

Dissection. — To  examine  the  encephalon  with  its  membranes,  the 
upper  part  of  the  skull  must  be  removed  by  sawing  through  the 
external  table,  and  breaking  the  internal  table  with  the  chisel  and 
hammer.  After  the  calvarium  has  been  loosened  all  round,  it  will 
require  a  considerable  degree  of  force  to  tear  the  bone  away  from 
the  dura  mater.  This  adhesion  is  particularly  firm  at  the  sutures, 
where  the  dura  mater  is  continuous  with  a  membranous  layer  inter- 
posed between  the  edges  of  the  bones ;  in  other  situations,  the  con- 
nexion results  from  numerous  vessels  which  permeate  the  inner 
table  of  the  skull.  The  adhesion  subsisting  between  the  dura  mater 
and  bone  is  greater  in  the  young  subject  than  in  the  adult. 

Upon  being  torn  away,  the  internal  table  will  present  the  deeply 
grooved  and  ramified  channels,  corresponding  with  the  branches  of 
the  arteria  meningea  magna.  Along  the  middle  line  will  be  seen  a 
groove  corresponding  with  the  superior  longitudinal  sinus,  and  on 
either  side  may  be  frequently  observed  some  depressed  fossae,  cor- 
responding with  the  Pacchionian  bodies. 

The  membranes  of  the  encephalon  are  the  dura  mater,  arachnoid 
membrane,  and  ipia  maier. 

The  Dura  mater*  is  the  firm,  bluish,  fibrous  membrane,  which  is 

*  So  named  from  a  supposition  that  it  was  the  source  of  all  the  fibrous  membranes 
of  the  body. 


388  DUEA  MATER. 

exposed  on  the  removal  of  the  calvavium.  It  lines  the  anterior 
of  the  skull  and  spinal  column,  and  sends  processes  inwards  for 
the  support  and  protection  of  the  diflerent  parts  of  the  brain.  It 
also  sends  processes  externally,  which  form  sheaths  for  the  nerves 
as  they  quit  the  skull  and  spinal  column.  Its  external  surface  is 
rough  and  fibrous,  and  corresponds  with  the  internal  table  of  the 
skull.  The  internal  surface  is  smooth,  and  lined  by  the  thin  varnish- 
like lamella  of  the  arachnoid  membrane.  The  latter  is  a  serous 
membrane.  Hence  the  dura  mater  becomes  a  iihro-serous  membrane, 
being  composed  of  its  own  proper  fibrous  structure,  and  the  serous 
layer  derived  from  the  arachnoid.  There  are  two  other  instances 
of  fibro-serous  membrane  in  the  body,  formed  in  the  same  way — 
the  pericardium  and  tunica  albuginea  of  the  testicle. 

On  either  side  of  the  dura  mater  the  branches  of  the  middle  me- 
ningeal artery  may  be  seen  ramifying  ;  and  in  the  middle  line  is  a 
depressed  groove,  formed  by  the  subsidence  of  the  upper  wall  of  the 
superior  longitudinal  sinus.  If  the  sinus  be  opened  along  its  course, 
it  will  be  found  to  be  a  triangular  channel,  crossed  at  its  lower 
angle  by  numerous  white  bands,  called  chordae  Willisii  ;*  granular 
bodies  are  also  occasionally  seen  in  its  interior;  these  are  glandulse 
Pacchioni. 

The  Glandulce  Pacchioni]  are  small,  round,  whitish  granulations, 
collected  into  clusters  of  variable  size.  They  are  found  in  three 
situations.  1.  On  the  inner  surface  of  the  dura  mater  near  to  the 
superior  longitudinal  sinus ;  when  of  large  size  they  produce  absorp- 
tion of  the  dura  mater,  and  considerable  indentations  on  the  inner 
wall  of  the  skull.  2.  In  the  superior  longitudinal  sinus.  3.  On  the 
arachnoid  membrane  investing  the  pia  mater  near  to  the  margin  of 

11-1  &  r  o 

the  hemispheres. 

If  the  student  cut  through  one  side  of  the  dura  mater,  along  the 
line  of  his  incision  through  the  skull,  and  turn  it  upwards  towards 
the  middle  line,  he  will  observe  the  smooth  internal  surface  of  the 
dura  mater.  He  will  perceive  also  the  large  cerebral  veins  filled 
with  dark  blood,  passing  from  behind  forwards  to  open  into  the 
superior  longitudinal  sinus,  and  the  firm  connexions,  by  means  of 
these  veins  and  the  Pacchionian  bodies,  between  the  opposed  sur- 
faces of  the  arachnoid  membrane. 

If  he  separate  these  with  his  scalpel,  he  will  see  a  vertical  layer 
of  dura  mater  descending  between  the  hemispheres,  and  if  he  draw 
one  side  of  the  brain  a  little  outwards,  he  will  distinctly  perceive  its 
extent;  this  is  the  falx  cerebri. 

The  processes  of  dura  mater  which  are  sent  inwards  towards  the 

*  Willis  lived  in  the  peventeenth  century  ;  he  was  a  great  defender  of  the  opinions  of 
Harvey. 

t  'i'hese  bodies  have  no  analog-y  whatsoever  with  glands.  Their  nature  and  nse  are 
but  imperfectly  known.  They  are  not  found  in  infancy.  Tlicy  are  described  as  con- 
globate glandri  by  Pacchioni,  in  an  epistolary  dissertation.  "  Do  Clandnlis  conglobatis 
Durae  Meningis  indcquc  ortis  Lyrnphaticis  ad  Piam  Matrem  productis,"  published  in 
Komc,  in  1705. 


DURA  MATER — PROCESSES.  389 

interior  of  the  skull,  are  the  falx  cerebri,  tentorium  cerebelH,  and 
falx  cerebelH. 

The  Falx  cerebri  (falx,  a  sickle),  so  named  from  its  sickle-like 
appearance,  narrow  in  front,  broad  behind,  and  forming  a  sharp 
curved  edge  below,  is  attached  in  front  to  the  crista  galli  process  of 
the  ethmoid  bone,  and  behind  to  the  tentorium  cerebelH. 

The  Tentorium  cerebelH  (tentorium,  a  tent)  is  a  roof  of  dura 
mater,  thrown  across  the  cerebellum,  and  attached  at  each  side  to 
the  margin  of  the  petrous  portion  of  the  temporal  bone,  behind  to 
the  transverse  ridge  of  the  occipital  bone,  which  lodges  the  lateral 
sinuses,  and  to  the  clinoid  processes  in  front.  It  supports  the  poste- 
rior lobes  of  the  cerebrum  and  prevents  their  pressure*  on  the 
cerebellum,  leaving  only  a  small  opening  anteriorly,  for  the  trans- 
mission of  the  crura  cerebri. 

The  Falx  cerebelH  is  a  small  process,  generally  double,  attached 
to  the  vertical  ridge  of  the  occipital  bone  beneath  the  lateral  sinus, 
and  to  the  tentorium.  It  is  received  into  the  indentation  between 
the  two  lateral  lobes  of  the  cerebellum. 

The  layers  of  the  dura  mater  separate  in  several  situations,  so  as 
to  form  irregular  channels  which  receive  the  venous  blood.  These 
are  the  sinuses  of  the  dura  mater;  they  are  described  at  page  356, 
in  the  Chapter  on  the  Veins. 

The  student  cannot  see  the  tentorium  and  falx  cerebelli  until  the 
brain  is  removed ;  but  he  should  consider  the  attachments  of  the 
tentorium  upon  the  dried  skull,  for  he  will  have  to  divide  it  in  the 
removal  of  the  brain.  He  should  now  proceed  to  that  operation, 
for  which  purpose  the  dura  mater  is  to  be  incised  all  round,  on  a 
level  with  the  section  through  the  skull,  and  the  scissors  are  to  be 
carried  deeply  between  the  hemispheres  of  the  brain  in  front,  to  cut 
through  the  anterior  part  of  the  falx ;  then  draw  the  dura  mater 
backwards,  and  leave  it  hanging  by  its  attachment  to  the  tentorium. 
Raise  the  anterior  lobes  of  the  brain  carefully  with  the  hand,  and 
lift  the  olfactory  bulbs  from  the  cribriform  fossae  with  the  handle  of 
the  scalpel.  Then  cut  across  the  two  optic  nerves  and  internal 
carotid  arteries.  Next  divide  the  infundibulum  and  third  nerve,  and 
carry  the  knife  along  the  margin  of  the  petrous  bone  at  each  side, 
so  as  to  divide  the  tentorium  near  its  attachment.  Cut  across  the 
fourth,  fifth,  sixth,  seventh,  and  eighth  nerves  in  succession  with  a 
sharp  knife,  and  pass  the  scalpel  as  far  down  as  possible  into  the 
vertebral  canal,  to  sever  the  spinal  cord,  cutting  first  to  one  side 
and  then  to  the  other,  in  order  to  divide  the  vertebral  arteries  and 
first  cervical  nerves.  Then  let  him  press  the  cerebellum  gently  for- 
wards with  the  fingers  of  the  right  hand,  the  hemispheres  being 
supported  with  the  left,  and  the  brain  will  roll  into  his  hand. 

The  Arteries  of  the  dura  mater  are  the  anterior  meningeal  from 
the  internal  carotid.     The  middle  meningeal  and  meningea  parva 

*  In  leaping  aniinuls,  as  the  feline  and  canine  genera,  the  tentorium  forms  a  bony 
tent. 

33* 


390  ARACHNOID  MEMBRANE. 

from  the  internal  maxillary.  The  inferior  memngeal  from  the 
ascending  pharyngeal  and  occipital  arteries;  and  the  posterior 
meningeal  from  the  vertebral. 

The  JN'eri'cs  are  derived  from  the  nervi  molles  and  vertebral  plexus 
of  the  sympathetic,  from  the  Casserian  ganglion,  the  ophthalmic 
nerve,  and  sometimes  from  the  fourth.  The  branches  from  the  two 
last  are  given  off  while  the  nerves  are  situated  by  the  side  of  the 
sella  turcica  ;  they  are  recuri'ent,  and  pass  backwards  between  the 
layers  of  the  tentorium,  to  the  lining  membrane  of  the  lateral  sinus. 

Arachnoid  Membrane. 

The  Arachnoid  {a^a-xyr\,  siSog,  like  a  spider's  web),  so  named  from 
its  extreme  tenuity,  is  the  serous  membrane  of  the  cerebro-spinal 
centre,  and  like  other  serous  membranes,  a  shut  sac.  It  envelopes 
the  brain  and  spinal  cord,  and  is  reflected  upon  the  inner  surface  of 
the  dura  mater,  giving  to  that  membrane  its  serous  investment. 

The  arachnoid  is  thin  and  transparent  on  the  upper  surface  of 
the  brain,  as  may  be  demonstrated  by  inserting  a  blowpipe,  and 
injecting  beneath  it  a  stream  of  air.  In  other  situations,  as  at  the 
base  of  the  brain  and  between  the  cerebellum  and  medulla  oblon- 
gata, it  is  semi-transparent  and  dense  in  structure,  and  is  rendered 
very  evident  by  passing  across  from  one  convexity  to  another,  and 
leaving  a  considerable  space  between  it  and  the  brain.  The  space 
which  is  thus  formed  between  the  arachnoid  membrane  and  the 
interval  of  the  base  of  the  brain  between  the  two  middle  lobes  of 
the  hemispheres,  has  been  called  by  Cruveilhier  the  anterior  sub- 
arachnoidean  space ;  and  that  intervening  between  the  posterior 
and  under  part  of  the  cerebellum  and  the  medulla  oblongata,  the 
posterior  sub-arachnoidean  space.  Both  these  spaces  communicate 
with  each  other  across  the  crura  cerebelli.  In  inflammation  of  the 
meninges,  this  membrane  is  often  thickened  and  opaque. 

The  arachnoid  is  attached  to  the  pia  mater  of  the  brain  by  a 
loose  cellular  tissue,  the  sub-arachnoidean.  This  tissue  is  fila- 
mentous at  the  base  of  the  brain,  and  between  the  hemispheres. 
Around  the  spinal  cord  the  arachnoid  is  disposed  very  loosely 
so  as  to  leave  a  considerable  space  between  it  and  the  spinal  cord. 
The  spinal  sub-arachnoidean  space  is  divided  by  a  partial  longitu- 
dinal septum  which  serves  to  connect  the  arachnoid  with  the  poste- 
rior surface  of  the  spinal  cord. 

The  Sub-arachnoidean  cellular  tissue  and  the  sub-arachnoidean 
spaces  are  the  seat  of  an  abundant  serous  secretion,  the  sub-arach- 
noidean fluid,  which  fills  all  the  vacuities  existing  between  the 
arachnoid  and  pia  mater,  and  distends  the  arachnoid  of  the  spinal 
cord  so  completely,  as  to  enable  it  to  occupy  the  whole  of  the  space 
included  in  the  sheath  of  dura  mater. 

The  arachnoid  also  secretes  a  serous  fluid  from  its  inner  surface, 
■which  is  small  in  quantity  compared  with  the  sub-arachnoidean 
liquid. 


PIA  MATER CEREBRUM.  391 

The  arachnoid  does  not  enter  into  the  ventricles  of  the  brain,  as 
imagined  by  Bichat,  but  is  reflected  inwards  upon  the  venae  Galeni 
for  a  short  distance  only,  and  returns  upon  those  vessels  to  the 
dura  mater  of  the  tentorium.  It  surrounds  the  nerves  as  they 
originate  from  the  brain,  and  forms  a  sheaih  around  them  to  their 
point  of  exit  from  the  skull.  It  is  then  reflected  back  upon  the  inner 
surface  of  the  dura  mater. 

There  are  no  vessels  in  the  arachnoid,  and  no  nerves  have  been 
traced  into  it. 

Pia  Mater. 

The  Pia  mater  is  a  vascular  membrane  composed  of  innumerable 
vessels  held  together  by  a  thin  cellular  layer.  It  invests  the  whole 
surface  of  the  brain,  dipping  into  its  convolutions,  and  forming  a 
fold  in  its  interior  called  vehim  interpositum.  It  also  forms  folds  in 
other  situations,  as  in  the  fourth  ventricle,  and  in  the  longitudinal 
grooves  of  the  spinal  cord. 

This  membrane  differs  very  strikingly  in  its  sti'ucture  in  different 
parts  of  the  cerebro-spinal  axis.  Thus,  on  the  surface  of  the  cere- 
brum, in  contact  with  the  soft  gray  matter  of  the  brain,  it  is  ex- 
cessively vascular,  forming  remarkable  loops  of  anastomoses  be- 
tween the  convolutions,  and  distributing  multitudes  of  m.inute 
straight  vessels  to  the  gray  substance.  In  the  substantia  perforata, 
again,  and  locus  perforatus,  it  gives  off  tufts  of  small  arteries, 
which  pierce  the  white  matter  to  reach  the  gray  substance  in  the 
interior.  But,  upon  the  crura  cerebri,  pons  Varolii,  and  spinal  cord, 
its  vascular  character  seems  almost  lost.  It  has  become  a  dense 
fibrous  membrane,  difficult  to  tear  off,  and  forming  the  proper  sheath 
of  the  spinal  cord. 

The  pia  mater  is  the  nutrient  membrane  of  the  brain,  and  derives 
its  blood  from  the  internal  carotid  and  vertebral  arteries. 

Its  JVerves  are  the  minute  filaments  of  the  sympathetic,  which 
accompany  the  branches  of  the  arteries. 

CEREBRUM. 

The  Cerebrum  is  divided  into  two  hemispheres  by  the  great  longi- 
tudinal fissure,  which  lodges  the  falx  cerebri,  and  marks  the  original 
developement  of  the  brain  by  two  symmetrical  halves. 

Each  hemisphere,  upon  its  under  surface,  admits  of  a  division 
into  three  lobes,  anterior,  middle,  and  posterior.  The  anterior  lobe, 
rests  upon  the  roof  of  the  orbit,  and  is  separated  from  the  middle  by 
the  fissure  of  Sylvius.*  The  middle  lobe,  is  received  into  the  middle 
fossa,  in  the  base  of  the  skull,  and  is  separated  from  the  posterior  by 

*  James  Dubois,  a  celebrated  professor  of  anatomy  in  Paris,  where  he  succeeded 
Vidius  in  1550,  although  known  much  earlier  by  liis  own  works  and  discoveries,  but 
particularly  by  his  violence  in  the  defence  of  Galen.  His  name  was  Latinised  to 
Jacobus  Sylvius. 


392  CEKTRUM  OVALE  MAJUS — CORPUS  CALLOSUM. 

a  slight  impression  produced  by  the  ridge  of  the  petrous  bone.  The 
posterior  lobe  is  supported  by  the  tentorium. 

If  the  upper  part  of  one  hemisphere  be  removed  with  a  scalpel, 
a  centre- of  white  surface  will  be  observed,  surrounded  by  a  narrow 
border  of  gray,  which  follows  the  depressions  of  the  convolutions, 
and  presents  a  zigzag  outline.  This  appearance  is  called  centrum 
ovale  minus.  The  divided  surface  will  be  seen  to  be  studded  with 
numerous  small  red  points  (puncta  vasculosa)  which  are  produced 
by  the  escape  of  blood  from  the  divided  ends  of  minute  arteries  and 
veins. 

Now  separate  carefully  the  two  hemispheres  of  the  cerebrum,  and 
a  broad  band  of  white  substance  will  be  seen  to  connect  them.  Re- 
move the  upper  part  of  each  hemisphere,  with  a  knife,  to  a  level 
with  this  white  layer.  The  appearance  resulting  from  this  section 
is  the  centrum  ovale  majus. 

The  Centrum  ovale  majus  is  the  large  centre  of  white  substance 
presented  to  view  on  the  removal  of  the  upper  part  of  both  hemi- 
spheres ;  it  is  surrounded  by  a  thin  stratum  of  gray  substance, 
which  follows  in  a  zigzag  line  all  the  convolutions  and  the  fissures 
between  them.  In  the  middle  of  the  centrum  ovale  majus  is  the 
broad  band  which  connects  the  two  hemispheres  to  each  other,  the 
corpus  callosum. 

The  Corpus  callosum  {callosus,  hard)  is  a  dense  layer  of  transverse 
fibres  connecting  the  two  hemispheres  and  constituting  their  great 
commissure.  It  is  situated  nearer  to  the  anterior  than  to  the  poste- 
rior part  of  the  brain,  and  terminates  anteriorly  in  a  rounded  border 
which  may  be  traced  downwards  to  the  base  of  the  biain,  in  front 
of  the  commissure  of  the  optic  nerves.  Posteriorly  it  forms  a  thick 
rounded  fold  which  is  continuous  with  the  fornix. 

Beneath  the  posterior  rounded  border  of  the  corpus  callosum  is 
the  transverse  fissure  of  the  cerebrum,  which  extends  between  the 
hemispheres  and  crura  cerebri  from  the  fissure  of  Sylvius  on  one 
side,  to  that  on  the  opposite  side  of  the  brain.  It  is  through  this 
fissure  that  the  pia  mater  communicates  with  the  velum  interpositum. 
And  it  was  here  that  Bichat  conceived  the  arachnoid  to  enter  the 
ventricles;  hence  it  is  also  named  the  fissure  of  Bichat. 

Along  the  middle  line  of  the  corpus  callosum  is  the  raphe,  a  linear 
depression  between  two  slightly  elevated  longitudinal  bands  ;  and,  on 
either  side  of  the  raphe,  may  be  seen  the  Unea.  transversce,  which 
mark  the  direction  of  the  fibres  of  which  the  corpus  callosum  is 
composed. 

If  an  incision  be  made  through  the  corpus  callosum  on  either  side 
of  the  raphe,  two  irregular  cavities  will  be  opened,  which  extend 
from  one  extremity  of  the  hemispheres  to  the  other  :  these  are  the 
lateral  ventricles.  To  expose  them  completely  the  upper  boundary 
should  be  removed  with  the  scissors. 

Each  lateral  ventricle  is  divided  into  a  central  cavity,  and  three 
smaller  cavities  called  cornua.  The  anterior  cornu  curves  forwards 
and  outwards  in  the  anterior  lobe :  the  middle  cornu  descends  into 


LATERAL  VENTBICLES. 


393 


the  middle  lobe ;  and  the  'posterior  cornu  passes  backwards  in  the 
posterior  lobe,  converging  towards  its  fellow  of  the  opposite  side. 
The  central  cavity  is  triangular  in  its  form,  being  bounded  above 
{roof)  by  the  corpus  callosum ;  internally  by  the  septum  lucidum, 
which  separates  it  from  the  opposite  ventricle  ;  and  below  {Jioor)  by 
the  following  parts,  taken  in  their  order  of  position  from  before 
backwards : 

Corpus  striatum, 
Tenia  semicircularis. 
Thalamus  opticus, 
Choroid  plexus, 
Corpus  fimbriatum, 
Fornix. 

Fig.  140. 


Fig.  140.  The  lateral  ventricles  of  the  cerebrum.  1,  I.  The  two  hemispheres  cut 
down  to  a  level  with  the  corpus  callosum  so  as  to  constitute  the  centrum  ovale  majus. 
The  surface  is  seen  to  be  studded  with  the  small  vascular  points — punuta  vasculosa ; 
and  surrounded  by  a  narrow  margin  which  represents  the  gray  substance.  2.  A  small 
portion  of  the  anterior  extremity  of  the  corpus  callosum.  8.  Its  posterior  boundary; 
the  intermediate  portion  forming  the  roof  of  the  lateral  ventricles  has  been  removed  so 
as  to  completely  expose  those  cavities.  4.  A  part  of  the  septum  lucidum,  showing  an 
interspace  between  its  layers — the  fifth  ventricle.  5.  The  anterior  cornu  of  one  side. 
6.  The  commencement  of  the  middle  cornu.  7.  The  posterior  cornu.  8.  The  corpus 
striatum  of  one  ventricle.  9.  The  tenia  semicircularis  covered  by  the  vena  corporis 
striata  and  tenia  Tarini.  10.  A  small  part  of  the  thalamus  opticus.  11.  The  dark 
fringe-like  body  to  the  left  of  the  figure  is  the  choroid  plexus.  This  plexus  communi- 
cates with  that  of  the  opposite  ventricle  through  the  foramen  of  Munro ;  a  bristle  is 
passed  through  this  opening,  and  its  extremities  are  seen  resting  on  the  corpus  striatum 
at  each  side.  The  figure  11  rests  upon  the  edge  of  the  fornix,  upon  that  part  of  it 
which  is  called  the  corpus  fimbriatum.  12.  The  fornix.  13.  The  commencement  of 
the  hippocampus  major  descending  into  the  middle  cornu.  The  rounded  oblong  body 
in  the  posterior  cornu  of  the  lateral  ventricle,  directly  behind  the  figure  13,  is  the  hip- 
pocampus minor. 


394  CORPUS  STRIATUM CHOROID  PLEXUS. 

The  Corpus  striatum  is  named  from  the  striated  lines  of  white 
and  gray  matter  which  are  seen  upon  cutting  into  its  substance.  It 
is  gray  on  the  exterior,  and  of  a  pyriform  shape.  The  broad  end, 
directed  forwards,  rests  against  the  corpus  striatum  of  the  opposite 
side:  the  small  end,  backwards,  is  separated  from  its  fellow  by  the 
interposition  of  the  thalami  optici.  The  corpora  striata  are  the 
superior  ganglia  of  the  cerebrum. 

The  Tenia  semicircularis  (tenia,  a  fillet)  is  a  narrow  band  of 
medullary  substance,  extending  along  the  posterior  border  of  the 
corpus  striatum,  and  serving  as  a  bond  of  connexion  between  that 
body  and  the  thalamus  opticus.  The  tenia  is  partly  concealed  by 
a  large  vein  {vena  corporis  striati)  formed  by  small  vessels  from  the 
corpus  striatum  and  thalamus  opticus,  and  terminating  in  the  venae 
Galeni.  The  vein  is  overlaid  by  a  yellowish  band,  a  thickening  of 
the  lining  membrane  of  the  ventricle.  This  was  first  noticed  and 
described  by  Tarinus,  under  the  name  of  the  horny  band.  We  may, 
therefore,  term  it  tenia  Tarini.* 

The  Thalamus  opticus  (thalamus,  a  bed)  is  an  oblong  body,  hav- 
ing a  thin  coating  of  white  substance  on  its  surface  ;  it  has  received 
its  name  from  giving  origin  to  one  root  of  the  optic  nerve.  It  is  the 
inferior  ganglion  of  the  cerebrum.  The  border  only  of  the  thalamus 
is  seen  in  the  floor  of  the  lateral  ventricle.  We  must,  therefore, 
defer  its  further  description  until  we  can  examine  it  in  its  entire 
extent. 

The  Choroid  plexus  (xopiov,  sTSos,  resembling  the  chorionf)  is  a  vas- 
cular fringe  extending  obliquely  across  the  floor  of  the  lateral  ven- 
tricle, and  sinking  into  the  middle  cornu.  Anteriorly,  it  is  small  and 
tapering,  and  communicates  with  the  choroid  plexus  of  the  opposite 
ventricle,  through  a  large  oval  opening,  ihe  foramen  of  Munro.  This 
foramen  may  be  distinctly  seen  by  pulling  slightly  on  the  plexus, 
and  pressing  aside  the  septum  lucidum  with  the  handle  of  the  knife. 
It  is  situated  between  the  under  surface  of  the  fornix,  and  the  anterior 
extremities  of  the  thalami  optici,  and  forms  a  transverse  communi- 
cation between  the  lateral  ventricles,  and  below  with  the  third 
ventricle. 

The  choroid  plexus  is  variable  in  its  appearance,  and  sometimes 
presents  groups  and  clusters  of  small  serous  cysts,  which  have  been 
mistaken  for  hydatids. 

The  Corpus' fiinhri alum  is  a  narrow  white  band,  which  is  situated 
immediately  behind  the  choroid  plexus,  and  extends  with  it  into  the 
descending  cornu  of  the  lateral  ventricle.  It  is  the  lateral  thin  edge 
of  the  fornix. 

The  Fornix  is  a  white  layer  of  medullary  substance,  of  which  a 
portion  only  is  seen  in  this  view  of  the  ventricle. 

The  Anterior  cornu  is  triangular  in  its  form,  sweeping  outwards 

*  Peter  Tarin,  a  French  anatomist :  iiis  work,  entitled  "  Adversaria  Anatomica,"  was 
puljlinhed  in  17.")0. 

t  See  tlie  note  appended  to  tiie  description  oftlic  choroid  eoatof  the  eyeball. 


CORNUA  OF  THE  LATERAL  VENTRICLES.  395 

and  terminatino;  by  a  point  in  the  anterior  lobe  of  the  brain,  at  a 
short  distance  only  from  its  surface. 

The  Posterior  cornu  or  digital  cavity  curves  inwards,  as  it  extends 
into  the  posterior  lobe  of  the  brain,  and  likewise  ternninales  near  to 
the  surface.  An  elevation  corresponding  with  a  deep  sulcus  between 
two  convolutions  projects  into  the  area  of  this  cornu,  and  is  called 
the  hippocampus  minor. 

The  Middle  or  descending  cornu,  in  descending  into  the  middle 
lobe  of  the  brain,  forms  a  very  considerable  curve,  and  alters  its 
direction  several  times  as  it  proceeds.  Hence  it  is  described  as 
passing  backwards  and  outwards  and  downwards,  and  then  turning 
forwards  and  inwards.  This  complex  expression  of  a  very  simple 
curve  has  given  birth  to  a  symbol  formed  by  the  primary  letters  of 
these  various  terms ;  and  by  means  of  this  the  student  recollects 
■with  ease  the  course  of  the  cornu,  bodfi.  It  is  the  largest  of  the 
three  cornua. 

The  middle  cornu  should  now  be  laid  open,  by  inserting  the  little 
finger  into  its  cavity,  and  making  it  serve  as  a  director  for  the 
scalpel  in  cutting  away  the  side  of  the  hemisphere,  so  as  to  expose 
it  completely. 

Its  Superior  boundary  is  formed  by  the  under  surface  of  the  thala- 
mus opticus,  upon  which  are  the  tw^o  projections  called  corpus 
geniculatum  internum  and  externum ;  and  the  inferior  loall  by  the 
various  parts  which  are  often  spoken  of  as  the  contents  of  the  middle 
cornu :  these  are  the — 

Hippocampus  major, 
Pes  hippocampi, 
Pes  accessorius. 
Corpus  fimbriatum, 
Choroid  plexus, 
Fascia  dentata, 
Transverse  fissure. 

The  Hippocampus  major  or  cornu  Ainmonis,  so  called  from  its  re- 
semblance to  a  ram's  horn,  the  famous  crest  of  Jupiter  Ammon,  is  a 
considerable  projection  from  the  inferior  wall,  and  extends  the  whole 
length  of  the  middle  cornu.  Its  extremity  is  likened  to  the  club-foot 
of  some  anim.al,  from  its  presenting  a  number  of  knuckle-like  eleva- 
tions upon  the  surface:  hence  it  is  named  pes  hippocampi.  The 
hippocampus  major  is  the  termination  of  the  lateral  edge  of  the 
hemisphere,  which  in  this  situation  is  very  much  attenuated  and 
rolled  upon  itself.  If  it  be  cut  across,  the  section  will  be  seen  to  re- 
semble the  extremity  of  a  convoluted  scroll,  consisting  of  alternate 
layers  of  white  and  gray  substance.  The  hippocampus  major  is 
continuous  superiorly  with  the  fornix  and  corpus  callosum. 

The  Pes  accessorius  is  a  swelling  somewhat  resembling  the  hippo- 
campus major,  but  smaller  in  size;  it  is  situated  on  the  outer  wall 
of  the  cornu,  and  is  frequently  absent. 

The  Corpus  fimbriatum  is  the  narrow  white  band  which  is  pro- 


396  FASCIA  DENTATA — FORNIX. 

longed  from  the  central  cavity  of  the  ventricle,  and  is  attached  along 
the  inner  border  of  the  hippocampus  major  to  its  termination. 

Fascia  dentala  : — If  the  corpus  fimbriatum  be  carefully  raised,  a 
narrow  serrated  band  of  gray  substance  will  be  seen  beneath  it ; 
this  is  the  fascia  dentata. 

Beneath  the  corpus  fimbriatum  will  be  likewise  seen  the  transverse 
fissure  of  the  brain,  which  has  been  before  described  as  extending 
from  the  fissure  of  Sylvius  on  one  side,  across  to  the  same  fissure 
on  the  opposite  side  of  the  brain.  It  is  through  this  fissure  that  the 
pia  mater  communicates  with  the  choroid  plexus,  and  the  latter  ob- 
tains its  supply  of  blood.  The  fissure  is  bounded  on  one  side  by  the 
corpus  fimbriatum,  and  on  the  other  by  the  under  surface  of  the 
thalamus  opticus. 

The  internal  boundary  of  the  lateral  ventricle  is  the  septum  luci- 
dum.  This  septum  is  thin  and  semi-transparent,  and  consists  of 
two  laminee  of  cerebral  substance  attached  above  to  the  under  sur- 
face of  the  corpus  callosum  at  its  anterior  part,  and  below  to  the 
fornix.  Between  the  two  layers  is  a  narrow  space,  the  fifth  ven- 
tricle, which  is  lined  by  a  proper  membrane.  The  fifth  ventricle 
may  be  shown,  by  snipping  through  the  septum  lucidum  transversely 
with  the  scissors. 

The  corpus  callosum  should  now  be  cut  across  towards  its  ante- 
rior extremity,  and  the  two  ends  carefully  dissected  away.  The 
anterior  portion  will  be  retained  only  by  the  septum  lucidum,  but 
the  posterior  will  be  found  incorporated  with  the  white  layer  beneath, 
which  is  the  fornix. 

l^he  fornix  (arch)  is  a  triangular  lamina  of  white  substance,  broad 
behind,  and  extending  into  each  lateral  ventricle :  narrow  in  front, 
where  it  terminates  in  two  crura,  which  arch  downwards  to  the 
base  of  the  brain.  The  two  crura  descend  through  the  foramen 
commune  anterius  of  the  third  ventricle,  and  terminate  in  the  cor- 
pora  albicantia.  Opening  transversely  beneath  these  two  crura, 
just  as  they  are  about  to  arch  downwards,  is  the  foramen  of  Munro, 
through  which  the  two  lateral  ventricles  communicate,  and  the  cho- 
roid plexuses  are  connected  anteriorly. 

The  lateral  thin  edges  of  the  fornix  are  continuous  posteriorly 
with  the  concave  border  of  the  hippocampus  major  at  each  side, 
and  form  the  narrow  white  band  called  corpus  fimbriatum.  In  the 
middle  line  the  fornix  is  continuous  with  the  corpus  callosum,  and 
at  each  side  with  the  hippocampus  major  and  minor.  Upon  the 
under  surface  of  the  fornix  towards  its  posterior  part,  some  trans- 
verse lines  are  seen  passing  between  the  diverging  lateral  fasciculi : 
this  appearance  is  termed  the  lyra,  from  a  fancied  resemblance  to 
the  strings  of  a  harp. 

The  fornix  may  now  be  removed  by  dividing  it  across  anteriorly, 
and  turning  it  backwards,  at  the  same  time  separating  its  lateral 
connexions  with  the  hippocampi.  If  the  student  examine  its  under 
surface,  he  will  perceive  the  lyra  above  described. 

Beneath  the  fornix  is  the  velum,  inter positum,  a  reflection  of  pia 


THALAMI  OPTICI. 


397 


mater  introduced  into  the  interior  of  the  brain,  through  the  trans- 
verse fissure.  The  velum  is  connected  at  each  side  with  the  choroid 
plexus,  and  contains  within  its  two  layers,  in  the  middle  line,  two 
large  veins,  the  venm  Galeni,  which  receive  the  blood  from  the 
ventricles,  and  terminate  posteriorly  in  the  straight  sinus.  Upon 
the  under  surface  of  the  velum  interpositum  are  two  fringe-like 
bodies  which  project  into  the  third  ventricle.  These  are  the  choroid 
plexuses  of  the  third  ventricle. 

Fig.  141. 


If  the  velum  interpositum  be  raised  and  turned  back,  an  operation 
which  must  be  conducted  with  care,  particularly  at  its  posterior  part, 
where  it  invests  the  pineal  gland,  the  thalami  optici  and  the  cavity 
of  the  third  ventricle  will  be  brought  into  view. 

The  tlialami  optici  are  two  rounded  oblong  bodies,  of  a  white 
colour  superficially,  inserted  between  the  two  diverging  portions  of 
the  corpora  striata.  In  the  middle  line  a  fissure  exists  between 
them,  which  is  called  the  third  ventricle.  Posteriorly  and  inferiorlv, 
they  form  the  superior  wall  of  the  descending  cornu,  and  present 

Fig.  141.  The  mesial  surface  of  a  longitudinal  section  of  the  brain.  The  incision 
has  been  carried  along  the  middle  line ;  between  the  two  hemispheres  of  the  cerebrum 
and  through  the  middle  of  the  cerebellum  and  medulla  oblongata.  1.  The  inner  sur- 
face of  the  left  hemisphere.  9.  The  divided  surface  of  the  cerebellum,  showing  the 
arbor  vitse.  3.  The  medulla  oblongata.  4.  The  corpus  callosum,  rounded  before  to 
terminate  in  the  base  of  the  brain  ;  and  behind,  to  become  continuous  with  5,  the  fornix. 
6.  One  of  the  crura  of  the  fornix  descending  to  7,  one  of  the  corpora  albicantia.  8. 
Thfe  septum  lucidum.  9.  The  velum  interpositum,  communicating  with  the  pia  mater 
of  the  convolutions  through  the  fissure  of  Bichat.  10.  Section  of  the  middle  commis- 
sure situated  in  the  third  ventricle.  11.  Section  of  the  anterior  commissure.  12.  Sec- 
tion .of  the  posterior  commissure  ;  the  commissure  is  somewhat  above  and  to  the  left  of 
the  number.  The  interspace  between  10  and  II  is  the  foramen  commune  anterius,  in 
which  the  crus  of  the  fornix  (6)  is  situated.  The  interspace  between  10  and  12  is  the 
foramen  commune  posterius.  13.  The  corpora  quadrigemina,  upon  which  is  seen 
resting  the  pineal  gland,  14.  15.  The  iter  e  tertio  ad  quartum  ventriculum.  16.  The 
fourth  ventricle.  17.  The  pons  Varolii,  through  which  are  seen  passing  the  divcrtring 
fibres  of  the  corpora  pyramidalia.  18.  The  crus  cerebri  of  tlie  left  side,  with  tiio  third 
nerve  arising  from  it.  19.  The  tuber  cinereum,  from  which  projects  the  infandibulum 
having  the  pituitary  gland  appended  to  its  extremity.  20.  One  of  the  optic  nerves.  21. 
The  left  olfactory  nerve  terminating  anteriorly  in  a  rounded  bulb. 

34 


398  THIRD  VENTRICLE. 

two  rounded  elevations  called  corpus  geniculaium  externum  and 
internum.  The  corpus  geniculaium  externum  is  the  larger  of  the 
two,  and  of  a  grayish  colour;  it  is  the  principal  origin  of  the  optic 
nerve.  "  Inferiorly,  the  thaiami  are  connected  with  the  corpora  albi- 
cantia  by  means  of  two  white  bands,  which  appear  to  originate  in 
the  white  substance  uniting  the  thaiami  to  the  corpora  striata.  In 
their  interi(jr  the  tlialami  are  composed  of  white  fibres  mixed  with 
gray  substance.  They  are  essentially  the  inferior  ganglia  of  the 
cerebrum. 

The  Third  ventricle  is  the  fissure  between  the  two  thaiami  optici. 
It  is  bounded  above  by  the  under  surface  of  the  velum  interpositum, 
from  which  are  suspended  the  choroid  plexuses  of  the  third  ventricle. 
Its  foor  is  formed  by  the  anterior  termination  of  the  corpus  callosum, 
the  tuber  cinereum,  corpora  albicantia,  and  locus  perforatus.  Late- 
rally  it  is  bounded  by  the  thaiami  optici  and  part  of  the  corpora 
striata;  anteriorly  by  the  anterior  commissure  and  crura  of  the 
fornix;  and  posteriorly  by  the  posterior  commissure  and  the  iter  e 
tertio  ad  quartum  vcntriculum. 

The  third  ventricle  is  crossed  by  three  commissures,  the  anterior, 
middle,  and  posterior;  and  between  these  are  two  spaces,  called 
foramen  commune  anterius  and  foramen  commune  posterius. 

The  Anterior  commissure  is  a  rounded  white  cord,  which  enters 
the  corpus  striatum  at  either  side  ;  the  middle,  or  soft  commissure 
consists  of  gray  matter,  and  is  very  easily  broken  down  ;  it  connects 
the  adjacent  sides  of  the  thaiami  optici:  and  the  posterior  commis- 
sure is  a  flattened  white  cord,  connecting  the  two  thaiami  optici 
posteriorly. 

Between  the  anterior  and  middle  commissure  is  the  space  called 
foramen  commune  anterius,  which,  from  leading  downwards  into 
the  infundibulum,  is  also  designated  iter  ad  infundihulum.  The 
crura  of  the  fornix  descend  through  this  space,  surrounded  by  gray 
matter  to  the  corpora  albicantia.  Between  the  middle  and  poste- 
rior commissure  is  the  foramen  com.mune  posterius,  frotn  which  a 
canal  leads  backwards  to  the  fourth  ventricle,  the  iter  e  tertio  ad 
quartum  ventriculum. 

Behind  the  third  ventricle  is  placed  the  quadrifid  ganglion  called 
optic  lobes  in  the  inferior  animals,  and  corpora  quadrigemiva  in 
man.  The  two  anterior  of  these  bodies  are  the  larger,  and  are 
named  vales;  the  two  posterior,  iesfes.  Their  base  is  perforated 
from  before  backwards  by  a  tubular  canal,  which  serves  to  com- 
municate the  third  and  fourth  ventricles,  and  is  thence  named  the 
iter  e  tertio  ad  quartum  ventriculum,  or  aqueduct  of  Sylvius. 
Resting  upon  the  corpora  quadrigemina  and  surrounded  by  a 
sheath  of  pia  mater,  obtained  from  the  velum  interpositum,  with 
which  it  is  liable  to  be  torn  off  unless  very  great  care  be  used,  is 
the  pineal  gland. 

The  Pineal  gland  consists  of  soft  gray  substance,  and  is  of  a 
conical  form  ;  hence  one  of  its  synonymes,  conarium.  It  contains 
in  its  interior  several  brownish  granules,  which  are  composed  of 


CHOROID  PLEXUSES.  399 

phosphate  and  carbonate  of  lime.  It  is  connected  to  the  ihalami 
oplici  by  two  small  rounded  cords,  called  'peduncles,  and  is  very 
improperly  called  a  gland. 

Behind  the  corpora  quadrigemina  is  the  cerebellum,  and  beneath 
the  cerebellum  tlie  fourth  ventricle.  The  student  must  therefore 
divide  the  cerebellum  down  to  the  fourth  ventricle,  and  turn  its 
lobes  aside  to  examine  that  cavity. 

The  Fourth  ventricle  is  the  ventricle  of  the  medulla  oblongata, 
upon  the  posterior  surface  of  which  it  is  placed.  It  is  an  oblong 
quadrilateral  cavity,  bounded  on  each  side  by  a  thick  cord  passing 
between  the  cerebellum  and  corpora  quadrigemina,  called  the  'pro- 
cessus e  cereheUo  ad  testes,  and  by  the  corpus  restiforme.  It  is 
covered  in  behind  by  the  arch  of  the  cerebellum,  which  forms  three 
remarkable  projections  into  its  cavity,  named,  from  their  resem- 
blance, uvula  and  tonsils :  and  by  a  thin  lamella  of  white  substance, 
stretched  between  the  two  processus  e  cerebello  ad  testes,  termed 
the  V(jloe  of  Vieussens.*  This  layer  is  easily  broken  down,  and 
requires  that  care  be  used  in  its  demonstration,  hi  front  the  fourth 
ventricle  is  bounded  by  the  posterior  surface  of  the  medulla  oblon- 
gata;  above  by  the  corpora  quadrigemina,  and  the  termination  of 
the  iter  e  tertio  ad  quartum  ventriculum;  and  beloiv  by  a  layer  of 
pia  mater  and  one  of  arachnoid,  passing  between  the  under  su  face 
of  the  cerebellum  and  the  medulla  oblongata,  called  the  valve  of  the 
arachnoid. 

We  observe  within  the  fourth  ventricle  the  choroid  plexuses,  the 
calamus  sciptorius,  and  the  linece  transversce. 

Tlie  Choroid  plexuses  resemble  in  miniature  those  of  the  lateral 
ventricles :  they  are  formed  by  the  pia  mater,  and  lie  against  that 
part  of  the  cerebellum  called  uvula  and  tonsils. 

The  anterior  wall,  or  floor,  of  the  fi:)urth  ventricle  is  formed  of 
gray  substance,  which  is  continuous  with  that  contained  within  the 
spinal  cord.  This  gray  substance  is  separated  into  two  bands  by 
a  median  fissure,  which  is  continuous  with  the  calamus  scriptorius. 
The  two  bands  are  considered  by  Mr.  Solly  as  the  two  posterior 
pyramids  ;  and  he  has  observed  in  their  structure  such  an  arrange- 
ment of  fibres  as  induces  him  to  name  them  the  '■^posterior  ganglia 
of  the  medulla  oblongata,"  in  opposition  to  the  corpora  olivaria, 
which  he  describes  as  the  "  anterior  ganglia  of  the  medulla." 

The  Calamus  scriptorius  is  a  groove  upon  the  anterior  wall,  or 
floor,  of  the  fourth  ventricle.  Its  pen-like  appearance  is  produced 
by  the  divergence  of  the  posterior  median  columns,  the  feather  by 
the  linese  transversse.  At  the  point  of  the  pen  is  a  small  cavity 
lined  with  gray  substance,  and  called  the  ventricle  of  Arantius. 

The  LinecB  transversa^  are  irregular  transverse  lines  upon  the 
anterior  wall  of  the  ventricle,  which  in  some  degree  resemble  the 
plume  of  the  pen.  They  are  the  filaments  of  origin  of  the  auditory 
nerve. 

*  Raymond  Vieussens,  a  great  discoverer  in  the  anatomy  of  the  brain  and  nervous 
system.     His  "  Neurographia  Universalis"  was  published  at  Lyons,  in  1685. 


400  CEREBELLUM. 

The  existence  of  a  communication  between  the  fourth  ventricle 
and  the  subarachnoidean  space,  as  imagined  by  Magendie,  is  very 
questionable. 

LINING    MEMBRANE     OF     THE     VENTRICLES. 

The  lining  membrane  of  the  ventricles  is  a  serous  layer,  quite 
distinct  from  the  arachnoid,  and  having  no  communication  with  it. 
This  membrane  lines  the  whole  of  the  interior  of  the  lateral  ventri- 
cles, and  is  connected  above  and  below  to  the  attached  border  of 
the  choroid  plexus,  so  as  to  exclude  completely  all  communication 
between  the  ventricles  and  the  exterior  of  the  brain.  It  is  reflected 
through  the  foramen  of  Munro,  on  each  side,  into  the  third  ventricle, 
which  it  invests  throughout.  From  the  third  it  is  conducted  into 
the  fourth  ventricle,  through  the  iter  e  tertio  ad  quartum  ventriculum, 
and  lines  its  interior,  together  with  the  layer  of  pia  mater  which 
forms  its  inferior  boundary.  In  this  manner  a  perfect  communica- 
tion is  established  between  all  the  ventricles.  It  is  this  membrane 
"which  gives  them  their  polished  surface,  and  transudes  the  secretion 
which  moistens  their  interior.  When  the  fluid  accumulates  to  an 
unnatural  degree,  it  may  then  break  down  this  layer  and  the  layer 
of  pia  mater  at  the  bottom  of  the  fourth  ventricle,  and  thus  make  its 
way  into  the  subarachnoidean  cellular  tissue;  but  in  the  normal 
condition  it  is  doubted  whether  a  communication  exists  between 
the  interior  of  the  ventricles  and  the  cavity  of  the  subarachnoidean 
space. 

CEREBELLUM. 

The  Cerebellum,  according  to  Cruveilhier,  is  seven  times  smaller 
than  the  cerebrum.  Like  that  organ  it  i?  composed  of  white  and 
gray  substance,  whereof  the  gray  is  larger  in  proportion  than  the 
white.  Its  surface  is  formed  by  parallel  lamellce,  separated  by 
fissures ;  and  at  intervals  deeper  fissures  exist,  which  divide  it  into 
larger  segments  termed  lobules.  The  cerebellum  is  divided  into 
two  lateral  hemispheres  or  lobes,  two  minor  lobes  called  superior 
and  inferior  vermiform  processes,  and  some  small  lobules. 

The  Z/rtiera/ /o6es  are  separated  from  each  other  posteriorly  by 
a  depression  which  lodges  the  falx  cerebelli,  and  above  and  below 
by  the  projection  of  the  vermiform  processes. 

The  Superior  vermiform  process,  a  slightly  elevated  ridge  along 
the  middle  of  the  upper  surface  of  the  cerebellum,  is  all  that  exists 
of  that  organ  in  birds,  and  it  constitutes  the  largest  proportion  of 
the  cerebellum  in  many  mammalia.  It  is  situated  along  the  middle 
line,  and  serves  to  connect  the  lateral  lobes  superiorly. 

The  Inferior  vermiform  process,  forms  a  projection  inferiorly,  and 
is  the  means  of  connexion  between  the  lateral  lobes  below. 

The  principal  lobules  are  the  pneumogastric,  the  tonsils,  uvula, 
and  lingiietta  laminosa. 

The  Pneumogaslric  lobule  (flocculus)  is  situated  on  the  anterior 
border  of  the  cerebellum,  near  to  the  origin  of  the  eighth  pair  of 


BASE  OF  THE  BRAIN.  401 

nerves,  and  is  hence  called  pneumogastric.  It  is  not  unlike  a  con- 
voluted shell  in  its  form. 

The  Tonsils  and  uvula  resemble  those  organs  in  a  swollen  state 
very  strikingly;  they  project  from  the  under  surface  of  the  cere- 
bellum into  the  fourth  ventricle. 

The  Livguetla  laminosa  is  a  thin  tonguelet  of  gray  substance, 
marked  by  transverse  furrows,  which  extend  forwards  upon  the 
valve  of  Vieussens  from  the  gray  substance  of  the  cerebellum. 

When  cut  into  vertically,  the  cerebellum  presents  the  appearance 
termed  arbor  vitce.  If  the  incision  be  made  through  the  outer  third 
of  the  organ,  a  gray  body,  surrounded  by  a  yellow  zigzag  line  of 
horny  structure,  will  be  seen  in  the  centre  of  the  white  substance : 
this  is  the  corpus  rhomboideum,  or  ganglion  of  the  cerebellum. 

The  cerebellum  is  associated  with  the  spinal  cord  and  cerebrum 
by  three  pairs  of  peduncles;  the 

Corpora  restiformia, 
Processus  e  cerebello  ad  testes, 
Crura  cerebelli. 

The  Corpora  restiformia,  or  inferior  peduncles,  diverge  at  the 
upper  extremity  of  the  medulla  oblongata,  and  enter  the  cerebellum, 
forming,  by  their  divergence,  part  of  the  lateral  boundaries  of  the 
fourth  ventricle.  Their  fibres  surround  the  corpus  rhomboideum, 
and  are  expanded  into  the  lamellae  of  the  cerebellum. 

The  Processus  e  cerebello  ad  testes  are  the  superior  peduncles: 
they  ascend  from  the  corpus  rhomboideum,  on  each  side,  to  the 
testis,  and  also  form  a  part  of  the  lateral  boundaries  of  the  fourth 
ventricle.  The  valve  of  Vieussens,  by  connecting  the  two  pro- 
cessus e  cerebello  ad  testes  from  side  to  side,  and  the  cerebellum 
and  testes  from  behind  forwards,  also  contributes  to  the  antero-pos- 
terior  communication  of  the  cerebellum. 

The  Crura  cerebelli  are  the  terminations  of  the  transverse  fibres 
of  the  pons  Varolii,  or  great  commissure  of  the  cerebellum,  which 
serves  to  establish  a  transverse  communication  between  the  lateral 
lobes. 

EASE     OF     THE     BRAIN. 

The  student  should  now  prepare  to  study  the  base  of  the  brain : 
for  this  purpose  the  organ  should  be  turned  upon  its  incised  surface  ; 
and  if  the  dissection  have  hitherto  been  conducted  with  care,  he 
will  find  the  base  perfectly  uninjured.  The  arachnoid  membrane, 
some  parts  of  the  pia  mater,  and  the  circle  of  Willis,  must  be  care- 
fully cleared  away  in  order  to  expose  all  the  structures.  These  he 
will  find  arranged  in  the  follovvinsr  order  from  before  backwards  : — 

Longitudinal  fissure, 
Olfactory  nerves, 
Fissure  of  Sylvius, 
Substantia  perforata, 
34* 


402  BASE  OF  THE  BEAIX. 

Commencement  of  the  transverse  fissure, 

Optic  commissure, 

Tuber  cinereum, 

Infundibulum, 

Corpora  albicantia, 

Locus  perforatus, 

Crura  cerebri, 

Pons  Varolii, 

Crura  cerebelli. 

Medulla  oblongata. 

The  Longitudinal  fissure  is  the  space  separating  the  two  hemi- 
spheres :  it  is  continued  downwards  to  the  base  of  the  brain,  and 
divides  the  two  anterior  lobes.  In  this  fissure  the  anterior  cerebral 
arteries  ascend  towards  the  corpus  callosum ;  and,  if  the  tvi^o  lobes 
be  slightly  drawn  asunder,  the  anterior  extremity  of  the  corpus  cal- 
losum will  be  seen  descending  to  the  base  of  the  brain. 

On  each  side  of  the  longitudinal  fissure,  upon  the  under  surface 
of  each  anterior  lobe,  is  the  olfactory  nerve,  with  its  bulb. 

The  Fissure  of  Sylvius  bounds  the  anterior  lobe  posteriorly,  and. 
separates  it  from  the  middle  lobe ;  it  lodges  the  middle  cerebral 
artery.  If  this  fissure  be  followed  outwards,  a  small  isolated  cluster 
of  convolutions  will  be  observed  ;  these  constitute  the  island  of  Reil, 

The  Substantia  'perforata  is  a  triangular  plane  of  white  substance, 
situated  at  the  inner  extremity  of  the  fissure  of  Sylvius.  It  is  named 
'perforata,  from  being  pierced  by  a  number  of  openings  for  small 
arteries,  which  enter  the  brain  in  this  situation  to  supply  the  gray 
substance  of  the  corpus  striatum. 

Passing  backwards  on  each  side  beneath  the  edge  of  the  middle 
lobe,  is  the  commencement  of  the  great  transverse  fissure,  which 
extends  beneath  the  hemisphere  of  one  side  to  the  same  point  on  the 
opposite  side. 

The  Optic  commissure  is  situated  on  the  middle  line ;  it  is  the 
point  of  communication  between  the  two  optic  nerves. 

The  Tuber  cinereum  is  an  eminence  of  gray  substance  immediately 
behind  the  optic  commissure,  and  connected  with  its  posterior  bor- 
der.    It  forms  part  of  the  floor  of  the  third  ventricle. 

The  Infundibulum  is  a  tubular  process  of  gray  substance,  opening 
from  the  centre  of  the  tuber  cinereum,  and  attached  below  to  the 
pituitary  gland,  which  is  lodged  in  tjie  sella  turcica.  Tiiis  gland 
is  retained  witliin  the  sella  turcica  by  the  dura  mater  and  arachnoid, 
and  is  with  great  difficulty  removed  with  the  brain.  It  is,  therefore, 
better  left  in  its  place,  where  it  is  intended  to  study  afterwards  the 
base  of  the  skull ;  for  any  attempt  at  removal  would  injure  the 
cavernous  sinuses.  It  consists  of  two  lobes,  but  presents  nothing 
glandular,  either  in  structure  or  function. 

The  Corpora  albicantia  are  two  rounded  white  bodies,  placed  side 
by  side,  of  about  the  size  of  peas ;  hence  their  synonyme  pisiformia. 
Thev  are  the  anterior  extremities  of  the  crura  of  the  fornix,  and  are 


MEDULLA  OBLONGATA.  403 

connected  with  the  thalami  optici  by  two  white  cords,  which  may 
be  easily  traced. 

The  Locus  perforatits  is  a  layer  of  whitish  gray  substance,  con- 
nected in  front  with  the  corpora  albicantia,  and  on  each  side  with 
the  crura  cerebri,  between  which  it  is  situated.  It  is  perforated  by 
several  thick  tufts  of  arteries,  which  are  distributed  to  the  thalami 
optici  and  third  ventricle,  of  which  it  assists  in  forming  the  floor.  It 
is  sometimes  called  the  pons  Tarini. 

The  Crura  cerebri  are  two  thick  white  cords  which  issue  from 
beneath  the  pons  Varolii,  and  diverge  to  each  side  to  enter  the  tha- 
lami optici.  The  third  nerve  will  be  observed  to  arise  from  the 
inner  side  of  each,  and  the  fourth  nerves  wind  around  them  from 
above.  If  the  crus  cerebri  be  cut  across,  it  will  be  seen  to  present, 
in  the  centre  of  the  section,  the  locus  niger. 

The  Pons  Varolii*  (protuberantia  annularis)  is  the  broad  trans- 
verse band  of  white  fibres,  which  arches  like  a  bridge  across  the 
upper  part  of  the  medulla  oblongata;  and,  contracting  on  each  side 
into  a  thick  rounded  cord,  enters  the  substance  of  the  cerebellum 
under  the  name  of  crus  cerebelli.  There  is  a  groove  along  its  mid- 
dle which  lodges  the  basilar  artery.  The  pons  Varolii  is  the  com- 
missure of  the  cerebellum,  and  associates  the  two  lateral  lobes  in 
their  common  function.  Resting  upon  the  pons,  near  its  posterior 
border,  is  the  sixth  pair  of  nerves.  On  the  anterior  border  of  the 
crus  cerebelli,  at  each  side,  is  the  thick  bundle  of  filaments  belonging 
to  the  fifth  nerve,  and,  lying  on  its  posterior  border  the  seventh  pair 
of  nerves. 

The  Medulla  oblongata  is  the  upper  enlarged  portion  of  the  spinal 
cord.  Upon  its  anterior  surface  are  seen  two  narrow  projecting 
columns,  the  corpora  pyramidalia.  These  bodies  are  broad  above, 
and  narrow  below ;  and,  at  the  point  where  they  enter  the  pons  Va- 
rolii, they  become  considerably  constricted.  They  are  connected 
to  each  other  in  the  middle  fissure,  at  about  an  inch  below  the  pons, 
by  a  decussation  of  their  fibres,  which  form  small  interlacing  bands 
crossing  from  side  to  side. 

Externally  to  the  corpora  pyramidalia  are  two  oblong  and  rounded 
bodies  supposed  to  resemble  olives  in  their  form,  and  hence  called 
corpora  olivaria.  If  these  bodies  be  divided  by  a  longitudinal  sec- 
tion, a  gray  zigzag  outline,  resembling  the  corpus  rhomboideum  of 
the  cerebellum,  will  be  seen  in  the  interior  of  each.  This  is  the 
ganglion  of  the  corpus  olivare. 

Behind  the  corpus  olivare  is  a  narrow  white  band,  which  de- 
scends along  the  side  of  the  medulla  oblongata  at  the  bottom  of  the 
lateral  sulcus.  This  is  the  situation  of  the  respiratory  tract  of  Sir 
Charles  Bell. 

*  Constant  Varolius,  Professor  of  Anatomy  in  Bologna  ;  died  in  1578.  He  dissected 
the  brain  in  the  course  of  its  fibres,  beginning  from  tlie  medulla  oblongata  :  a  plan 
which  has  since  been  perfected  by  Vieu-scns,  and  by  Gall  and  Spurzheim.  The  work 
containing  his  mode  of  dissection,  "  Re  IJesoIutione  Corporis  Humani,"  was  published 
after  his  death,  in  1591. 


404 


MEDULLA  OBLONGATA. 


The  Corpora  resiiformia  (restis,  a  rope)  are  the  remaining 
columns,  of  the  medulla  oblongata;  they  form  its  posterior  segment, 
and  diverge  superiorly  to  enter  the  cerebellum.  Between  the  two 
corpora  resiiformia  posteriorly  are  two  other  white  bands,  which 
diverge  at  the  pcjint  of  the  calamus  scriptorius,  and  join  the  corpora 
restiformia  :  these  are  the  posterior  median  fasciculi  of  the  medulla 
oblongata. 

Fig.  142. 


If  a  thin  layer  of  the  pons  Varolii  be  carefully  raised,  or  if  a 
longitudinal  incision  be  made  across  it,  it  may  easily  be  seen  that 
the  corpus  pyramidale  passes  through  the  pons  into  the  crus  cerebri. 
If  the  crus  cerebri  be  traced  forwards,  it  will  be  found  to  enter  the 
thalamus  opticus,  and  leaving  it  by  the  opposite  border  to  plunge 

Fi^.  142.  The  under  surface  or  base  of  the  brain.  1.  The  anterior  lobe  of  one  hemi- 
sphere of  the  cerebrum.  2.  The  middle  lobe.  3.  The  posterior  lobe  almost  concealed 
by  (4)  the  lateral  lobe  of  the  cerebellum.  5.  The  inferior  vermiform  process  of  the 
cerebellum.  6.  The  pneumogastric  lobule.  7.  The  longitudinal  fissure.  8.  The 
olfactory  nerves,  with  their  bulbous  expansions.  9.  The  substantia  perforata  at  the 
inner  termination  of  the  fissure  of  Sylvius  ;  the  three  roots  of  the  olfactory  nerve  are 
seen  uptm  the  substantia  perforata.  The  commencement  of  the  transverse  fissure  on 
each  side  is  concealed  by  the  inner  border  of  the  middle  lobe.  10.  The  commissure  of 
the  optic  nerves.  II.  The  tuber  cinereum,  from  which  the  infimdibulum  is  seen  pro- 
jecting. 12.  The  corpora  albic.inlia.  13.  The  locus  perforatus  bounded  on  each  side 
by  the  crura  cerebri,  and  by  the  third  nerve.  14.  The  pons  Varolii.  1.5.  The  crus 
cerebelli  of  one  side.  IG.  The  fifth  nerve  emerging  from  the  anterior  border  of  the 
crus  cerebelli ;  the  small  nerve  by  its  side  is  the  fourth.  17.  The  sixth  pair  of  nerves. 
18.  The  seventh  pair  of  nerves  consisting  of  the  auditory  and  facial,  li).  The  corpora 
pyramidalia  of  the  medulla  oblongata;  tiie  corpus  olivare  and  part  of  the  corpus  resti- 
forme  are  seen  at  caf:h  sifie.  Just  below  the  number  is  tlie  decussation  of  the  fibres 
of  the  corpora  pyramidalia.  20.  The  eighth  pair  of  nerves.  21.  The  ninth  or  hypo- 
glossal nerve.     22.  Tlie  anterior  root  of  the  first  cervical  spinal  nerve. 


FIBRES  OF  THE  BRAIJV. 


405 


into  the  corpus  striatum,  and  pass  from  thence  onwards  to  the  con- 
volutions of  the  hemispheres. 


Fiff.  143. 


From  pursuing  this  remarkable  course,  and  spreading  out  as  they 
advance,  these  fibres  have  been  called  by  Gall  the  diverging  fibres. 
While  situated  within  the  pons  it  is  found  that  the  fibres  of  the  cor- 
pus  'pyramidale  separate  and  spread  out,  and  have  gray  substance 
interposed  between  them  ;  and  that  they  quit  the  pons  much  in- 
creased in  number  and  bulk,  so  as  to  form  the  cms  cerebri.  The 
fibres  of  the  crus  cerebri  again  are  separated  in  the  thalamus 
opticus,  and  are  intermingled  with  gray  matter,  and  they  also  quit 
that  body  greatly  increased  in  number  and  bulk.  Precisely  the 
same  change  takes  place  in  the  corpus  striatum,  and  the  fibres  are 
now  so  extraordinarily  multiplied  as  to  be  capable  of  forming  a 

Fig^.  143.  The  base  of  the  brain,  upon  which  several  sections  have  been  made, 
showings  the  distribution  of  the  diverging  fibres.  1.  The  medulla  oblongata.  2.  One 
half  of  the  pons  Varolii.  3.  The  crus  cerebri  crossed  by  the  optic  nerve  (4)  and 
spreading  out  into  the  substance  of  the  middle  lobe.  5.  The  two  roots  of  the  optic 
nerve ;  the  nerves  about  the  crus  cerebri  and  cerebelli  are  the  same  as  in  the  preceding 
figure.  6.  The  olfactory  nerve.  7.  The  corpora  albicantia.  On  the  right  side  a  por- 
tion  of  the  brain  has  been  removed  to  show  the  distribution  of  the  diverging  fibres.  8. 
The  fibres  of  the  corpus  pyramidale  passing  through  the  substance  of  the  pons  Varolii. 
9.  The  fibres  passing  through  the  thalamus  opticus.  10.  The  fibres  passing  through 
the  corpus  striatum.  11.  Their  distribution  to  the  hemispheres.  12.  The  fitlh  nerve; 
its  two  roots  may  be  traced,  the  one  forwards  to  the  fibres  of  the  corpus  pyramidale, 
the  other  backwards  to  the  corpus  rcstiforme.  13.  The  fibres  of  the  corpus  pyramidale 
which  pass  outwards  with  the  corpus  rcstiforme  into  the  substance  of  the  cerebellum ; 
these  are  the  arciform  fibres  of  Solly.  The  number  rests  upon  the  upper  part  of 
the  corpus  olivare;  the  rest  of  that  body  having  been  cut  away,  the  arciform  fibres  are 
below  the  number.  14.  A  section  through  one  of  the  lateral  lobes  of  tlie  cerebellum, 
showing  the  corpus  rhomboideum  in  the  centre  of  its  white  substance;  the  arbor  vitse 
is  also  beautifully  seen.     15.  The  opposite  lobe  of  the  cerebellum. 


406  DIVERGING  FIBRES. 

large  proportion  of  the  hemispheres,  viz.,  the  whole  of  the  lower 
part  of  the  anterior  and  middle  lobes. 

From  observing  this  remarkable  increase  in  the  white  fibres, 
apparently  from  the  admixture  of  gray  substance,  Gall  and  Spurz- 
heim  considered  the  latter  as  the  material  increase  of  formative 
substance  to  the  white  fibres,  and  they  are  borne  out  in  this  conclu- 
sion by  several  collateral  facts,  among  the  most  prominent  of  which 
is  the  great  vascularity  of  the  gray  substance;  and  the  larger  pro- 
portion of  the  nutrient  fluid  circulating  through  it,  is  fully  capable 
of  affecting  the  increased  growth  and  nutrition  of  the  structures  by 
which  it  is  surrounded.  For  a  like  reason  the  bodies  in  which  this 
gray  substance  occurs,  are  called  by  the  same  physiologists  "gan- 
glia of  increase,^'  and  by  other  authors  simply  ganglia.  Thus  the 
thalami  optici  and  corpora  striata  are  the  ganglia  of  the  cerebrum; 
or,  in  other  words,  the  formafive  ganglia  of  the  hemispheres. 

Mr.  Solly,  in  a  recent  work  upon  "  the  human  brain,"  has  desig- 
nated the  diverging  fibres  of  the  corpus  pyramidale  that  pursue  the 
course  above  described,  "  the  cere/^rt// //ires  ;"  to  distinguish  them 
from  another  set  of  fibres  discovered  by  that  gentleman,  which  also 
proceed  from  the  corpus  pyramidale,  and  pass  outward  beneath  the 
corpus  olivare  to  the  cerebellum.  These  he  names  the  "  arciform 
fibres"  and  divides  them  into  two  layers,  the  superficial  cerebellar 
and  deep  cerebellar  fibres.  They  join  the  corpus  restiforme,  forming 
one-fourth  of  its  whole  diameter,  and  spread  out  in  the  structure  of 
the  cerebellum. 

The  Copora  olivaria  owe  their  convex  olive-shaped  form  to  a 
"ganglion  of  increase"  (the  anterior  ganglia  of  the  medulla  oblon- 
gata of  Solly),  situated  in  the  interior  of  each. 

The  white  fibres  surrounding  these  ganglia  form  a  fasciculus  at 
each  side,  which  is  continued  into  the  pons  Varolii  along  with  the 
corpora  pyramidalia.  Here  its  fibres  are  mixed  with  gray  matter, 
and  pass  into  the  crus  cerebri,  forming  its  superior  and  inner  seg- 
ment. From  the  crus  cerebri  they  traverse  successively  the  thalamus 
opticus  and  corpus  striatum,  and  become  developed  into  the  convo- 
lutions of  the  upper  part  of  the  hemispheres  and  posterior  lobe. 

The  Corpora  resliformia  diverge  as  they  approach  the  cerebellum, 
and  leaving  between  them  the  cavity  of  the  fourth  ventricle  enter 
the  substance  of  the  cerebellum,  under  the  form  of  two  rounded 
cords.  These  cords  envelope  the  corpora  rhomboidea,  or  ganglia 
of  increase,  and  then  expand  on  all  sides  so  as  to  constitute  the 
cerebellum. 

In  addition  to  the  diverging  fibres  which  are  thus  shown  to  con- 
stitute both  the  cerebrum  and  cerebellum,  by  their  increase  and 
developement,  another  set  of  fibres  are  found  to  exist,  which  have 
for  their  office  the  association  of  the  symmetrical  halves,  and  distant 
parts  of  the  same  hemis[)hercs. 

These  are  called  from  their  direction  converging  fibres,  and  from 
their  office  commissures.  The  commissures  of  the  cerebrum  and 
cerebellum  are  the — 


SPINAL  COKD.  407 

Corpus  callosum, 
Fornix, 

Septum  lucidum, 
Anterior  commissure, 
Middle  commissure, 
Posterior  commissure, 
Peduncles  of  the  pineal  gland, 
Processus  e  cerebello  ad  testes, 
Valve  of  Vieussens, 
Pons  Varolii. 

The  Corpus  callosum  is  the  commissure  of  the  hemispheres.  It 
is  therefore  of  moderate  thickness  in  the  middle,  where  its  fibres 
pass  directly  from  one  hemisphere  to  the  other ;  thicker  in  front, 
where  the  anterior  lobes  are  connected;  and  thickest  behind,  where 
the  fibres  from  the  posterior  lobes  are  assembled. 

The  Fornix  is  an  antero-posterior  commissure,  and  serves  to 
connect  a  number  of  parts.  Below,  it  is  associated  with  the  thalami 
optici ;  on  each  side,  by  means  of  the  corpora  fimbriata,  with  the 
middle  lobes  of  the  brain;  and,  above,  with  the  corpus  callosum, 
and  consequently  with  the  hemispheres. 

The  Septum  lucidum  is  a  perpendicular  commissure  between  the 
fornix  and  corpus  callosum. 

The  Anterior  commissure  traverses  the  corpus  striatum,  and  con- 
nects the  anterior  and  middle  lobes  of  opposite  hemispheres. 

The  Middle  commissure  is  a  layer  of  gray  substance,  uniting  the 
thalami  optici. 

The  Posterior  commissure  is  a  white  flattened  cord,  connecting 
the  thalami  optici. 

The  Peduncles  of  the  pineal  gland  must  also  be  regarded  as  com- 
missures, assisted  in  their  function  by  the  gray  substance  of  the 
gland. 

The  Processus  e  cerebello  ad  testes  are  the  means  of  communica- 
tion between  the  white  substance  of  the  cerebellum  and  cerebrum  ; 
and  the  linguetta  laminosa  and  valve  of  Vieussens  perform  the 
same  office  to  the  gray  substance. 

The  Pons  Varolii  is  the  commissure  to  the  two  lobes  of  the  cere- 
bellum. It  consists  of  transverse  fibres,  which  are  split  into  two 
layers  by  the  passage  of  the  fasciculi  of  the  corpora  pyramidalia 
and  olivaria.  These  two  layers,  the  superior  and  inferior,  are  col- 
lected together  on  each  side,  in  the  formation  of  the  crura  cerebelli. 

SPINAL     CORD. 

The  dissection  of  the  spinal  cord  requires  that  the  spinal  column 
should  be  opened  throughout  its  entire  length  by  sawing  through  the 
laminae  of  the  vertebree,  close  to  the  roots  of  the  transverse  processes, 
and  raising  the  arches  with  a  chisel,  after  the  muscles  of  the  back 
have  been  removed. 

The  Spinal  column  contains  the  spinal  cord,  or  medulla  spinalis; 


408  SPINAL  CORD. 

the  roots  of  the  spinal  nerves ;  and  the  membranes  of  the  cord,  viz., 
dura  mater,  arachnoid,  pia  mater,  and  membrana  dentata. 

'  The  Dura  mater  {t/ieca  vertebralis)  is  continuous  with  the  dura 
mater  of  the  skull:  it  is  closely  attached  around  the  border  of  the 
occipital  foramen,  particularly  in  front,  where  it  is  connected  with 
the  posterior  common  ligament.  In  the  vertebral  canal  it  is  con- 
nected only  by  loose  cellular  tissue,  containing  an  oily  fluid,  some- 
what analogous  to  the  marrow  of  long  bones.  On  either  side  and 
below,  it  forms  a  sheath,  for  each  of  the  spinal  nerves,  to  which  it 
is  closely  adherent.  Upon  its  inner  surface  it  is  smooth,  being  lined 
by  the  arachnoid ;  and  on  the  sides  may  be  seen  the  double  openings 
for  the  two  roots  of  each  of  the  spinal  nerves. 

The  Arachnoid  is  a  continuation  of  the  serous  membrane  of  the 
brain.  It  encloses  the  cord  very  loosely,  being  connected  to  it  only 
by  long  slender  cellular  filaments,  and  by  a  longitudinal  lamella 
which  is  attached  to  the  posterior  aspect  of  the  cord.  It  passes  off 
on  either  side  with  the  spinal  nerves,  to  which  it  forms  a  sheath  ; 
and  is  then  reflected  upon  the  dura  mater,  to  constitute  its  serous 
surface.  A  connexion  exists  in  several  situations  between  the  arach- 
noid of  the  cord  and  that  of  the  dura  mater. 

The  space  between  the  arachnoid  and  the  spinal  cord  is  identical 
with  that  already  described  as  existing  between  the  same  parts  in 
the  brain,  the  subarachnoidean  space.  It  is  occupied  in  both  by  a 
serous  fluid,  sufficient  in  quantity  to  expand  the  arachnoid,  and  fill 
completely  the  cavity  of  the  theca  vertebralis.  The  subarachnoi- 
dean fluid  keeps  up  a  constant  and  gentle  pressure  upon  the  entire 
surface  of  the  brain  and  spinal  cord,  and  yields  with  the  greatest 
facility  to  the  various  movements  of  the  cord,  giving  to  those  deli- 
cate structures  the  advantage  of  the  principles  so  usefully  applied 
by  Dr.  Arnott  in  the  hydrostatic  bed.  According  to  Magendie  this 
fluid  communicates  with  the  secretion  contained  in  the  lateral  ven- 
tricles, by  means  of  an  opening  which  exists  in  the  fibrous  layer 
of  the  inferior  boundary  of  the  fourth  ventricle.  / 

The  Pia  mater  is  the  immediate  investment  of  the  cord  ;  and,  like 
the  other  membranes,  is  continuous  with  that  of  the  brain.  It  is 
not,  however,  like  the  pia  mater  cerebri,  a  vascular  membrane:  but 
is  dense  and  fibrous  in  its  structure,  and  contains  very  few  vessels. 
It  invests  the  cord  closely,  and  sends  a  duplicate  into  the  sulcus 
jongitudinalis  anterior,  and  another,  extremely  delicate,  into  the 
sulcus  longitudinalis  posterior.  It  forms  a  sheath  for  each  of  the 
filaments  of  the  nerves,  and  for  the  nerves  themselves;  and,  infe- 
riorly,  at  the  conical  termination  of  the  cord,  is  prolonged  down- 
wards as  a  slender  ligament,  which  descends  through  the  centre  of 
the  Cauda  equina,  and  is  attached  to  the  dura  mater  lining  the  canal 
of  the  coccyx.  This  attachment  is  a  rudiment  of  the  original  ex- 
tension of  the  spinal  cord  into  the  canal  of  the  sacrum  and  coccyx. 

The  Membrana  dentata  is  a  process  of  the  pia  mater  sent  off"  from 
each  side  of  the  cord  throughout  its  entire  length,  and  separating 
the  anterior  from  the  posterior  roots  of  the  spinal  nerves.     Between 


MEDULLA  SPINALIS.  409 

each  of  the  nerves  it  forms  a  serration,  which  is  attached  to  the 
dura  mater,  and  unites  the  two  layers  of  the  arachnoid  membrane 
at  that  point.  The  processes  are  about  twenty  in  number  at  each 
side.  Their  use  is  to  maintain  the  position  of  the  spinal  cord  in  the 
midst  of  the  fluid  by  which  it  is  surrounded. 

The  Spinal  cord  of  the  adult  extends  from  the  pons  Varolii  to 
opposite  the  first  or  second  lumbar  vertebra,  where  it  terminates  in 
a  rounded  point;  in  the  child,  at  birth,  it  reaches  to  the  middle  of 
the  third  lumbar  vertebra,  and  in  the  embryo  is  prolonged  as  far  as 
the  coccyx.  It  presents  a  difference  of  diameter  in  difl^erent  parts 
of  its  extent,  and  exhibits  three  enlargements.  The  uppermost  of 
these  is  the  medulla  oblongata;  the  next  corresponds  with  the  origin 
of  the  nerves  destined  to  the  upper  extremities ;  and  the  lower 
enlargement  is  situated  near  to  its  termination,  and  corresponds 
with  the  attachment  of  the  nerves  which  are  intended  for  the  supply 
of  the  lower  limbs. 

In  form,  the  spinal  cord  is  a  flattened  cylinder,  and  presents  on 
its  anterior  surface  a  groove,  which  extends  into  the  cord  to  the 
depth  of  one  third  of  its  diameter.  This  is  the  sulcus  longitudinalis 
anterior.  If  the  sides  of  the  groove  be  gently  separated,  they  will 
be  seen  to  be  connected  at  the  bottom  by  a  layer  of  medullary 
substance,  the  anterior  commissure. 

On  the  posterior  surface  another  fissure  exists,  which  is  so  narrow 
as  to  be  hardly  perceptible  without  careful  examination.  This  is 
the  sulcus  longitudinalis  posterior.  It  extends  much  more  deeply 
into  the  cord  than  the  anterior  sulcus,  and  terminates  in  the  gray 
substance  of  the  interior.  These  two  fissures  divide  the  medulla 
spinalis  into  two  lateral  cords,  which  are  connected  to  each  other 
merely  by  the  white  commissure  which  forms  the  bottom  of  the 
anterior  longitudinal  sulcus. 

On  either  side  of  the  sulcus  longitudinalis  posterior  is  a  slight  line, 
which  bounds  on  each  side  the  posterior  median  columns.  These 
columns  are  most  apparent  at  the  upper  part  of  the  cord,  near  to  the 
fourth  ventricle,  where  they  are  separated  by  the  point  of  the  cala- 
mus scriptorius,  and  where  they  form  a  bulbous  enlargement  at 
each  side,  called  the  -processus  clavatus. 

Two  other  lines  are  observed  on  the  medulla,  the  anterior  and 
posterior  lateral  sulci,  corresponding  with  the  attachment  of  the 
anterior  and  posterior  roots  of  the  spinal  nerves.  The  anterior 
lateral  sulcus  is  a  mere  trace,  marked  only  by  the  attachment  of  the 
filaments  of  the  anterior  roots.  The  posterior  lateral  sulcus  is  more 
evident,  and  is  formed  by  a  narrow  grayish  fasciculus  derived  from 
the  gray  substance  of  the  interior. 

These  sulci  divide  the  medulla  into  four  fasciculi  or  cords,  viz. — 

Anterior  columns, 
Lateral  columns. 
Posterior  columns, 
Median  posterior  columns. 
35 


410 


COLUMNS  OF  THE  SPINAL  CORD. 


The  Anterior  are  the  motor  columns,  and  give  origin  to  the  motor 
roots  of  the  spinal  nerves.  They  are  continued  upward  into  the 
niedulla  oblongata,  under  the  form  of  corpora  'pyramidalia. 

The  Lateral  columns  are  divided  in  their  function  between  motion 
and  sensation,  and  contain  the  fasciculus  described  by  Sir  Charles 
Bell  as  the  respiratory  tract.  Some  anatomists  consider,  the  ante- 
rior and  lateral  column  on  each  side  as  a  single  column,  under  the 
name  of  antero-lateral. 

The  Posterior  are  the  columns  of  sensation,  and  give  origin  to  the 
sensitive  roots  of  the  spinal  nerves.  Their  superior  terminations 
are  named  corpora  restiformia. 

The  Median  posterior  columns  have  no  function  at  present  assigned 
to  them. 

If  a  transverse  section  of  the  spinal  cord  be  made,  its  internal 
structure  may  be  seen  and  examined.  It  would  then  appear  to  be 
composed  of  two  hollow  cylinders  of  white  matter,  placed  side  by 
side,  and  connected  by  a  narrow  white  commissure.  Each  cylinder 
is  filled  with  gray  substance,  which  is  connected  by  a  commissure 
of  the  same  matter.  The  form  of  the  gray  substance,  as  observed 
in  the  section,  is  that  of  two  half  moons  placed  back  to  back,  and 
joined  by  a  transverse  band.  The  horns  of  the  moons  correspond 
to  the  sulci  of  origin  of  the  anterior  and  posterior  roots  of  the  nerves. 
The  anterior  horns  do  not  quite  reach  this  surface;  but  the  posterior 
appear  upon  the  surface,  and  form  a  narrow  gray  line. 

Fig.  144. 


The  white  substance  of  the  spinal  cord  is  composed  of  parallel 
fibres,  which  are  collected  into  longitudinal  laminae  and  extend 
throughout  the  entire  length  of  the  cord.  These  lamina)  are  various 
in  breadth,  and  are  arranged  in  a  radiated  manner;  one  border  being 

Fig.  144.  Sections  of  the  spinal  marrow  in  different  portions  of  its  length.  1. 
Opposite  the  11th  dorsal  vertebra.  2.  Opposite  the  10th  dorsal.  3.  Opposite  the  8th 
dorsal.  4.  Opposite  the  Sth  dorsal.  5.  Opposite  the  7th  cervical.  6.  Opposite  the 
4th  cervical.  7.  Opposite  the  3d  cervical.  8.  Section  of  medulla  oblongata  through 
the  corpora  olivaria. 


CRANIAL  NERVES.  411 

thick  and  corresponding  with  the  surface  of  the  cord,  while  the  other 
is  thin  and  hes  in  contact  with  the  gray  substance  of  the  interior. 
According  to  Rolando  the  while  substance  constitutes  a  simple 
nervous  membrane  which  is  folded  into  longitudinal  plaits,  having 
the  radiated  disposition  above  described.  The  anterior  commissure, 
according  to  his  description,  is  merely  the  continuation  of  this  ner- 
vous membrane  from  one  lateral  cord  across  the  middle  line  to  the 
other.  Moreover,  Rolando  considers  that  a  thin  lamina  of  pia 
mater  is  received  between  each  of  the  folds  from  the  exterior, 
while  a  layer  of  the  gray  substance  is  prolonged  between  them 
from  within.  Cruveilhier  is  of  opinion  that  each  lamella  is  com- 
pletely independent  of  its  neighbours,  and  he  believes  this  statement 
to  be  confirmed  by  pathology,  which  shows  that  a  single  lamella 
may  be  injured  or  atrophied,  and  at  the  same  time  be  surrounded 
by  others  perfectly  sound. 

CRANIAL    NERVES. 

There  are  nine  pairs  of  cranial  nerves.     Taken  in  their  order 
from  before,  backwards,  they  are — 

1st.  Olfactory. 

2d.    Optic. 

3d.   Motores  oculorum. 

4th.  Pathetici  (trochleares). 

5th.  Trifiicial  (trigemini). 

6th.  Abducentes. 

,^,1    (  Facial  (portio  dura), 

\  Auditory  (portio  mollis), 

C  Glosso-pharyngeal, 
8th.  <  Pneumogastric  (vagus,  par  vagum). 

(  Spinal  accessory. 
9th.  Hypoglossal  (lingual). 

Functionally  or  physiologically  they  are  divided  into  four  groups, 
and  in  this  order  we  shall  examine  them. 

Nerves  of 

C  1st.  Olfactory, 

1.  Special  sense     .         .      <  2d.    Optic, 

^7th.  Auditory. 

(  3d.    Motores  oculorum, 

2.  Motion      .         .         .      ^  Gth.  Abducentes, 

(  9th.  Hypoglossal. 

(  4th.  Patheticus, 

3.  Respiration  {Bell)      .      }  7th.  Facial, 

(  8th.  Glosso-pharyngeal. 
Pneumogastric, 
Spinal  accessory. 

4.  Spinal     .         .         .  5th.  Trifacial. 


412 


OLFACTORY   NERVE. 


NERVES    OF    SPECIAL    SENSE. 

1st  pair,  Olfactory. — This  nerve  rests  against  the  under  surface 
of  the  anterior  lobe  of  the  brain,  being  lodged  in  the  narrow  interval 
between  two  convolutions,  and  retained  in  its  place  by  the  arachnoid 
membrane. 

It  arises  by  three  roots,  1.  Internal,  from  the  substantia  perforata. 
2.  Middle,  from  a  papilla  of  gray  matter  embedded  in  the, anterior 

lobe.    3.  External,  from 
Fig- 145.  a  long  fasciculus  which 

is  traced  for  a  consi- 
derable distance  along 
the  fissure  of  Sylvius, 
into  the  middle  lube. 
The  union  of  these 
roots  forms  a  grayish 
white  nerve,  prismoid 
in  form  and  soft  in 
structure,  which  ex- 
pands into  a  bulb  {bul- 
bus  olfactorius),  and 
rests  upon  the  cribri- 
form plate.  Its  bran- 
are  transmitted  through  the  numerous  foramina  in  the  cribri- 
form plate,  to  be  distributed  to  the  mucous  membrane  of  the  nose. 
The  innermost  are  reddish  in  colour  and  soft,  and  spread  out  upon 
the  septum  narium ;  the  external  branches  are  whiter  and  more 
firm,  they  pass  through  bony  canals  in  the  outer  wall  of  the  nose, 
and  communicate  freely  with  each  other  previously  to  their  distri- 
bution in  the  mucous  membrane  of  the  superior  and  middle  turbi- 
nated bones. 

2d  pair,  Optic. — The  optic  nerve  arises  by  two  roots  ;  one  from 
the  corpus  geniculatum  externum,  the  other  from  the  anterior  pair 
(nates)  of  the  corpora  qua drigemin a  or  optic  lobes.  It  winds  around 
the  crus  cerebri  as  a  flattened  band,  and  unites  with  its  fellow  of 
the  opposite  side,  to  form  the  commissure.  The  two  nerves  then 
diverge  from  each  other,  to  enter  the  orbit  through  the  optic  fora- 
men, pierce  the  sclerotic  and  choroid  coat  of  the  eyeball,  and  expand 
in  the  retina.  The  optic  commissure  rests  upon  the  processus  oli- 
varis  of  the  sphenoid  bone,  and  its  posterior  border  is  closely  con- 
nected with   the  tuber  cinereum,  from  which  it  receives   fibres ; 


ches 


Fig.  145.  A  view  of  the  1st  pair  or  olfactory,  wi(ti  the  nasal  branches  of  (he  5th. 
1.  Frontal  sinus.  2.  Spticnoidal  sinus.  3.  Hard  paliito.  4.  Bulb  of  the  olliictory 
nerve.  5.  Branches  of  the  olfactory  on  tlic  superior  and  middle  turbinated  bones,  6. 
Sphcno  palatine  nerves  from  the  2d  of  the  5th.  7.  Internal  nasal  nerve  from  the  1st 
of  the  5th.  8.  Branches  of  7,  to  Schneiderian  membrane.  9.  Ganglion  of  Cloquct  in 
the  foramen  incisivtim.  10.  Anastomosis  on  the  inferior  tuibinated  bone  of  the 
branches  of  the  5th  pair. 


OPTIC  NERVE AUDITORY  NERVE. 


413 


in    its    interior   the   innermost  ^'g-  ^'^^- 

fibres  of  the  two  nerves  cross 

each  other,  while  the  external 

proceed    directly    onwards    in 

their  course.     On  entering  the 

orbit  the  nerve  obtains  a  firm 

sheath   from    the   dura   mater, 

■which    is    continuous  with    the 

sclerotic   coat   of  the   eyeball. 

This   sheath  is  formed  by  the 

splitting  of  the  dura  mater  at 

the  foramen  opticum  into  two 

layers,  the  one  surrounding  the 

optic  nerve,  while  the  other  is 

continuous  with  the  periosteum 

of  the  orbit.     Near  to  the  globe 

of  the  eyeball  the  optic  nerve  is 

pierced  by  the  arteria  centralis 

retinae,  which  runs  forwards  in 

the   centre   of  the   nerve,  and 

reaching  the   retina  distributes 

branches  upon  its  internal  surface,  forming  its  vascular  layer. 

7th  pair.  Auditory  (portio  mollis.) — This  nerve  arises  from  the 
anterior  wall  or  floor  of  the 


fourth  ventricle,  by  means 
of  the  white  fibres,  linece 
transversce,  of  the  calamus 
scriptorius.  It  winds  around 
the  corpus  restiforme,  from 
which  it  receives  fibres,  and 
emerges  upon  the  posterior 
border  of  the  crus  cerebelli ; 
it  then  enters  the  meatus 
auditorius  internus,  together 
with  the  facial  nerve,  which 
lies  in  a  groove  on  its  supe- 
rior and  anterior  surface, 
and  at  the  bottom  of  the 
meatus    divides    into     two 


Fig.  147. 


Fig.  146.  A  view  of  the  2d  pair  or  optic,  and  the  origins  of  seven  other  pairs,  1,  I. 
Globe  of  the  eye,  the  one  on  the  left  hand  is  perfect,  but  that  on  the  right  has  the 
sclerotic  and  choroid  removed  to  sliow  the  retina.  2.  The  chiasm  of  the  optic  nerves. 
3.  The  corpora  albicantia.  4.  The  infundibulum.  5.  The  pons  Varolii.  6.  The 
medulla  oblnngala.  The  figure  is  on  the  riglit  corpus  pyramidale.  7.  'I'hc  3d  pair, 
motor es  oculi.  8.  4th  pair, /va//(e/icj.  9.  5lh  pair,  nio-p/ninf.  10.  6th  pair,  o/x/ucen^ps. 
11.  7th  pair,  auditory  and  facial.  12.  8lh  pair,  pneumogastric,  spinal  accessory,  and 
glosso-pharyngeal.     13.  9lh  pair,  hypoglossal. 

Fig.  147.  A  view  of  the  origin  and  distribution  of  the  portio  mollis  of  the  7th  pair  or 
audilory  nerve.  1.  The  medulla  oblongata.  2.  Tlie  pons  Varolii.  3,  and  4.  The 
crura  cerebelli  of  the  riglit  side.  5.  8th  pair.  6.  9th  pair.  7.  The  auditory  nerve 
distributed  to  the  cochlea  and  labyrinth.  8.  The  6tii  pair.  9.  The  portio  dura  of  the 
7th  pair.     10.  The  4th  pair.     11.  The  3d  pair. 

35* 


414 


MOTOKES  OCULORUM. 


branches,  cochlear  and  vestibular,  which  are  distributed  to  the 
internal  ear.  It  is  soft  and  pulpy  in  texture,  and  whilst  situated  in 
the  meatus  auditorius  sends  several  filaments  to  the  facial  nerve. 


NERVES    OF    MOTION. 

We  have  already  seen  that  the  corpora  pyramidalia  are  the  con- 
tinuations upwards-  of  the  anterior  columns  of  the  spinal  cord,  or 
motor  tract,  and  that  these  fasciculi  are  prolonged  onwards  through 
the  pons  Varolii  and  crura  cerebri  into  the  ganglia  of  the  hemi- 
spheres. Now,  the  three  motor  "nerves  arise  from  the  cerebral 
portion  of  the  motor  tract  at  different  points  of  its  course. 

Fig.  148. 


3d  pair,  Motores  Oculorum. — The  motor  oculi  nerve  arises  from 
the  inner  side  of  the  crus  cerebri,  near  to  the  pons  Varolii,  and 
passes  forward  between  the  posterior  cerebral  and  superior  cere- 
bellar artery.  It  pierces  the  dura  mater  immediately  in  front  of 
the  posterior  clinoid  process;  descends  obliquely  along  the  external 
wall  of  the  cavernous  sinus  ;  and  divides  into  two  branches,  which 
enter  the  orbit  between  the  two  heads  of  the  external  rectus  muscle. 
The  superior  branch  ascends,  and  supplies  the  superior  rectus  and 
levator  palpebroe.  The  ivferior  sends  a  branch  beneath  the  optic 
nerve  to  the  internal  rectus,  another  to  the  inferior  rectus,  and  a 
long  branch  to  the  inferior  oblique  muscle.   From  the  latter  a  short 

Fig.  148,  A  view  of  the  3d,  4tii,  and  6th  pairs  of  nerves.  1.  Ball  of  the  eye,  the 
rectus  extcrnus  mupcle  being  cut  and  hanging  down  from  its  origin.  2.  The  su- 
perior nrijixilla.  .3.  'J'he  3d  pair  or  motor  ocvli  distributed  to  all  the  muscles  of  the 
eye  except  the  superior  oblique  and  external  rectus.  4.  The  4lh  pair  or  palheticus 
going  to  the  superior  oblique  muscle.  5.  One  of  the  branches  of  the  .5th.  6.  The 
6th  pair  or  motor  exiernvs  distribiilrd  to  the  external  rcctu^i  muscle.  7.  Sphenopala- 
tine  ganglion  and  branches.  8.  Ciliary  nerves  from  the  lenticular  ganglion,  the  short 
root  of  which  is  seen  to  connect  it  with  the  3d  pair. 


ABDUCENTES HYPOGLOSSAL  NERVE. 


415 


thick  branch  is  given  off  to  the  ciliary  ganglion,  forming  its  infe- 
rior root. 

The  fibres  of  origin  of  this  nerve  may  be  traced  into  the  gray 
substance  of  the  crus  cerebri,*  into  the  motor  tracif  and  as  far  as 
the  superior  fibres  of  the  crus  cerebri. J  In  the  cavernous  sinus  it 
receives  one  or  two  filaments  from  the  cavernous  plexus,  and  one 
from  the  ophthalmic  nerve. 

6th  pair,  Abducentes. — The  abducens  nerve  arises  from  the  upper 
part  of  the  corpus  pyramidak,  close  to  the  pons  Varolii,  several  of 
its  filaments  of  origin  passing 

between    the    fasciculi    of   the  ^^S- 149. 

pons.  It  pierces  the  dura 
mater  upon  the  basilar  pro- 
cess of  the  sphenoid  bone,  and 
ascends  to  the  cavernous  sinus. 
It  then  runs  forward  along  the 
inner  wall  of  the  sinus,  below 
the  other  nerves ;  and,  resting 
against  the  inlernal  carotid 
artery,  passes  beneath  the  two 
heads  of  the  external  rectus, 
and  is  distributed  to  that  mus- 
cle. As  it  enters  the  orbit  it 
lies  upon  the  ophthalmic  vein, 
from  which  it  is  separated  by  a 
lamina  of  dura  mater.  In  the 
cavernous  sinus  it  is  joined  by 
two  filaments  from  the  carotid 
plexus,  and  by  one  from  the 
ophthalmic  nerve.  Mr.  Mayo 
has  traced  the  origin  of  this 
nerve  between  the  fasciculi  of 
the  corpora  pyramidalia  to  the  posterior  part  of  the  medulla  oblon- 

Fig.  149.  The  anatomy  of  the  side  of  the  neck,  showing-  the  nerves  of  the  tongue.  1. 
A  fragment  of  the  temporal  bone  containing  the  meatus  auditorius  externus,  mastoid, 
and  styloid  process.  2.  The  slylo-hyoid  muscle.  3.  The  stylo-glossus.  4.  Tiie  stylo- 
pharyngeus.  5.  The  tongue.  6,  The  hyo-glossus  muscle;  its  two  portions.  7.  The 
genio-hyo-glossus  muscle.  8.  The  genio-hyoideus  ;  they  both  arise  from  the  inner  sur- 
face of  the  symphysis  of  the  lower  jaw.  9.  The  sterno-hyoid  muscle.  10.  The  sterno- 
thyroid. 11.  7'he  thyro-hyoid,  upon  which  the  hyoid  branch  of  the  lingual  nerve  is 
seen  ramifying.  12.  The  omo-hyoid  crossing  the  common  carotid  artery  (13),  and  in- 
ternal jugular  vein  (14).  15.  The  external  carotid  giving  off  lis  branches.  16.  The 
internal  carotid.  17.  The  gustalory  nerve  giving  off  a  branch  to  the  submaxillary 
ganglion  (18),  and  communicating  a  litlle  further  T>n  with  the  hypoglossal  nerve.  19. 
The  submaxillary,  or  Wharton's  duct,  passing  forwards  to  the  sublinoual  gland.  20. 
The  glosso-pharyngeal  nerve.  21.  The  hypoglossal  nerve  curving  around  the  occipital 
artery.  22.  The  descendens  noni  nerve,  forming  a  loop  with  (23)  the  communicans 
noni,  which  is  seen  to  be  arising  by  filaments  from  the  upper  cervical  nerves.  21.  The 
pneumogastric  nerve,  emerging  from  between  the  intt  rneil  jugular  vein  and  common 
carotid  artery,  and  entering  the  chest.  2.5.  The  facial  nerve,  emerging  from  the  stylo- 
mastoid foramen,  and  crossing  the  external  carotid  artery. 

*  Mayo.  t  Solly.  \  Grainger. 


416  EESPIRATORY  NERVES, 

gata ;  and  I\Ir.  Grainger  has  pointed  out  its  connexion  with  the  gray 
substance  of  the  spinal  cord. 

■9th  pair,  Hypoglossal  (lingual).  The  ninth  nerve,  the  true  motor 
nerve  oF  the  tongue,  arises  by  eight  or  ten  filaments  from  the  side  of 
the  corpus  pyramidale  of  the  medulla  oblongata.  These  filaments 
are  disposed  in  two  fasciculi  which  unite  into  a  single  nerve  at  the 
posterior  condyloid  foramen.  The  lingual  nerve  then  passes  for- 
ward between  the  internal  carotid  artery  and  internal  jugular 
vein,  and  descends  along  the  anterior  and  inner  side  of  the 
vein  to  a  point  parallel  with  the  angle  of  the  lower  jaw.  It  next 
curves  inwards  around  the  occipital  artery,  with  which  it  forms 
a  loop,  and  crosses  the  lower  part  of  the  hyo-glossus  muscle  to  the 
genio-hyo-glossus,  in  which  it  terminates  by  sending  filaments  on- 
wards with  the  anterior  fibres  of  this  muscle  as  far  as  the  tip  of  the 
tongue.  It  is  distributed  to  the  muscles  of  the  tongue,  and  prin- 
cipally to  the  genio-hyo-glossus.  While  resting  on  the  hyo-glossus 
muscle  it  has  a  flattened  appearance,  and  communicates  beneath 
the  mylo-hyoideus  of  the  gustatory  nerve. 

The  Branches  of  the  hypoglossal  nerve  are : 

Communicating  branches  with  the  Pneumogaslric, 

Spinal  accessory. 
First  and  second  cervical 

nerves, 
Sympathetic. 

Descendens  noni, 

Hyoidean  branch. 

Communicating  filaments  with  the  gustatory  nerve. 

The  Communications  with  the  pneumogastric  and  spinal  acces- 
sory take  place  through  the  medium  of  a  plexiform  interlacement  of 
branches  at  the  base  of  the  skull,  behind  the  internal  jugular  vein. 
The  communications  with  the  sympathetic  nerve  are  derived  from 
the  superior  cervical  ganglion. 

The  Descendens  noni  is  a  long  slender  twig,  which  quits  the  hypo- 
glossal just  as  that  nerve  is  about  to  form  its  arch  around  the  occipi- 
tal artery,  and  descends  upon  the  sheath  of  the  carotid  vessels.  Just 
below  the  middle  of  the  neck  it  forms  a  loop  with  a  long  branch 
(communicans  noni)  from  the  second  and  third  cervical  nerves. 
From  the  convexity  of  this  loop  branches  are  sent  to  the  depressor 
muscles  of  the  larynx.  If  the  descendens  noni  be  traced  to  its  con- 
nexion with  the  hypoglossal  nerve,  and  examined  with  care,  it  will 
be  found  to  be  formed  by  two  filaments,  one  from  the  lingual,  the 
other,  of  larger  size,  from  the  first  and  second  cervical  nerves. 

The  Hijoidcan  branch  is  a  small  twig  distributed  to  the  insertions 
of  the  depressor  muscles  of  the  larynx,  particularly  to  the  thyro- 
hyoid. 

The  Communicating  filaments  with  the  gustatory  nerve  are  two 
or  three  small  branches  which  ascend  upon  the  anterior  part  of  the 


FACIAL  NERVE.  417 

hyo-glossus  muscle,  and  join  corresponding  branches  sent  down- 
wards by  the  gustatory. 

RESPIRATORY     NERVES. 

Under  this  head  are  grouped,  by  Sir  Charles  Bell,  certain  nerves 
which  are  associated  in  the  movements  of  respiration.  They  all 
arise  in  the  course  of  a  distinct  tract,  situated  between  the  corpus 
olivare  and  corpus  restiforme  on  each  side  of  the  medulla  oblongata, 
and  which  may  be  traced  upwards  to  the  corpora  quadrigemina; 
hence  this  portion  of  the  brain  has  been  named  the  respiratory 
tract. 

4th  pair,  Pathetici  (trochlearis). — The  fourth  is  the  smallest 
cerebral  nerve;  it  arises  from  the  valve  of  Vieussens  and  testis, and 
winds  around  the  crus  cerebri  to  the  extremity  of  the  petrous  por- 
tion of  the  temporal  bone,  where  it  pierces  the  dura  mater  near  to 
the  oval  opening  for  the  fifth  nerve,  and  passes  along  the  outer  wall 
of  the  cavernous  sinus  to  the  sphenoidal  fissure.  In  its  course 
through  the  sinus  it  is  situated  at  first  below  the  motor  oculi,  but 
afterwards  ascends  and  becomes  the  highest  of  the  nerves  which 
enter  the  orbit  through  the  sphenoidal  fissure. 

After  reaching  the  orbit  it  crosses  the  levator  palpebrge  muscle 
near  to  its  origin,  and  is  distributed  upon  the  orbital  surface  of  the 
superior  oblique  or  trochlearis  muscle ;  hence  its  synonyme  troch- 
learis. 

Branches. — While  in  the  cavernous  sinus  the  fourth  nerve  gives 
off  a  recurrent  branch  ;  some  filaments  of  communication  to  the 
ophthalmic  nerve;  and  a  branch  to  assist  in  forming  the  lachrymal 
nerve.  The  recurrent  branch  passes  backwards  between  the  layers 
of  the  tentorium  and  divides  into  two  or  three  filaments,  which  are 
distributed  to  the  lining  membrane  of  the  lateral  sinus.  In  a  prepa- 
ration before  me  this  branch  is  very  distinct ;  but  I  have  not  always 
succeeded  in  finding  it. 

7th  pair,  Facial  {portio  dura.)  The  Facial  nerve  arises  from 
the  respiratory  tract,  at  the  upper  part  of  the  medulla  oblongata 
close  to  the  lower  border  of  the  pons  Varolii,  from  which  point  its 
fibres  may  be  traced  deeply  into  the  corpus  restiforme.  It  enters 
the  meatus  auditorius  internus  in  front  of  and  superiorly  to  the  au- 
ditory nerve  (portio  mollis),  and  at  the  bottom  of  the  meatus  passes 
into  the  canal  which  is  expressly  intended  for  it,  the  aqueductus 
Fallopii.  In  this  canal  it  directs  its  course  at  first  forwards  towards 
the  hiatus  Fallopii,  where  it  forms  a  gangliform  swelling,  and  re- 
ceives the  petrosal  branch  of  the  Vidian  nerve.  It  then  curves 
backwards  towards  the  tympanum,  and  descends  along  its  inner 
wall  to  the  stylo-mastoid  foramen.  Emerging  at  the  stylo-mastoid 
foramen  it  passes  forwards  within  the  parotid  gland,  and  crosses  the 
external  jugular  vein  and  external  carotid  artery  to  the  ramus  of  the 
jaw\  While  situated  within  the  gland  it  is  joined  by  a  branch  from 
the  auricular  nerve,  and  divides  into  two  trunks — the  temporo-facial 


418  FACIAL  NERVE. 

and  cervi co-facial — which  communicate  with  each  other  and  give 
off  the  numerous  branches  which  constitute  the  pes  anserinus,  and 
are  distributed  over  the  whole  of  the  side  of  the  face,  supplying  the 
muscles. 

The  Branches  o^  \\\e  facial  nerve  are — 

Within   the   aqueductus     (  Tympanic, 
Fallopii,  I  (Chorda  tympani).* 

r  Communicating, 
After   emerging   at   the    j  Posterior  auricular, 
stylo-masioid foramen,    y  Digastric, 
C  Stylo-hyoid. 

r>    4K„  f  \  Temporo-facial, 

On  the  face,  \  r^      \      r    ■  u. 

^  (  Cervico-iacial.j 

The  Tympanic  branches  are  two  small  filaments,  which  are  dis- 
tributed to  the  stapedius  and  tensor  tympani  muscle. 

The  Chorda  tympani  quits  the  facial  just  before  that  nerve  emerges 
from  the  stylo-mastoid  foramen.  Entering  the  tympanum  at  its 
posterior  and  superior  angle,  it  crosses  its  cavity  between  the  handle 
of  the  malleus  and  long  process  of  the  incus,  to  its  anterior  inferior 
angle.  It  then  escapes  through  a  distinct  opening  in  the  fissura 
Glaseri,  and  joins  the  gustatory  nerve  at  an  acute  angle  between 
the  two  pterygoid  muscles.  Enclosed  in  the  sheath  of  the  gustatory 
nerve,  it  descends  to  the  submaxillary  gland,  where  it  unites  with 
the  submaxillary  ganglion. 

The  Communicating  branches  are  filaments  which  it  receives 
from  the  glosso-pharyngeal  and  pneumogastric  nerves. 

The  Posterior  auricular  nerve  ascends  behind  the  ear,  and  crosses 
the  mastoid  process  to  the  occipito-frontalis  muscle ;  it  gives 
branches  also  to  the  attoUens  and  retrahens  muscles  of  the  pinna. 

The  Digastric  branch  supplies  the  posterior  belly  of  the  digas- 
tricus  muscle. 

The  Stylo-hyoid  branch  is  distributed  to  the  stylo-hyoid  muscle. 

The  Temporo-facial  gives  off  a  number  of  branches  which  are 
distributed  over  the  temple  and  upper  half  of  the  face,  supplying  the 
muscles  of  this  region,  and  communicating  with  the  branches  of  the 
auricular,  the  temporo-malar,  and  the  supra-orbital  nerve.  The  in- 
ferior branches,  which  accompany  Stenon's  duct,  form  a  plexus 
with  the  terminal  branches  of  the  infra-orbital  nerve. 

The  Cervico-facial  divides  into  a  number  of  branches  that  are 
distributed  to  the  muscles  on  the  lower  half  of  the  face,  and  upper 

*  The  chorda  tympani  is  not  considered  as  a  branch  of  the  facial ;  but  being  in  close 
connexion  with  it,  and  being'  given  off  from  it  liiic  a  branch,  I  have  inserted  it  here 
lest  it  should  be  overlooked. 

t  A  third  series  of  branches  is  usually  described,  which  arc  included  by  Wilson  in 
histem|)oro-facial  branchcH.  They  are  called  buccal,  from  supplying  the  neighbourhood 
of  the  buccinator  muscle. — G. 


FACIAL  NERVE. 


419 


part  of  the  neck.     The  cervical  branches  form  a  plexus  with  the 
superficialis  colli  nerve  over  the  submaxillary  gland. 


Fi-r.  150. 


The  facial  nerve  has  been  named  sympatheticus  minor,  on  account 
of  the  number  of  communications  which  it  maintains  with  other 
nerves.     These  will  be  best  seen  in  a  tabular  arrangement: 


In  the  petrous  hone  it 
communicates  with 

At  its  exit  from  the 
styh-mastoid  fora- 
men, with 


Auditory  nerve, 

Petrosal  branch  of  Vidian, 


Otic  ganglion. 


Glosso-pharyngeal, 
Pneumogastric. 


Fig.  150.  The  distribution  of  the  facial  nerve  and  the  branches  of  the  cervical  plexus. 
1.  The  facial  nerve,  escaping  from  the  stylo-mastoid  foramen,  and  crossing  the  ramus  of 
the  lower  jaw  ;  the  parotid  gland  has  been  removed  in  order  to  see  the  nerve  more  dis- 
tinctly. 2.  The  posterior  auricular  branch ;  the  digastric  and  stylo-mastoid  filaments 
are  seen  near  the  origin  of  this  branch.  3.  Temporal  branches,  communicating  with 
(4)  the  branches  of  the  frontal  nerve.  5.  Facial  branches,  communicating  with  (6)  the 
infra-orbital  nerve.  7.  Facial  branches,  communicating  with  (8)  the  mental  nerve.  9. 
Cervico-facial  branches  communicating  with  (10)  the  superficialis  colli  nerve,  and 
forming  a  plexus  (11)  over  the  submaxillary  gland.  The  distribution  of  the  branches 
of  the  facial  in  a  radiated  direction  over  the  side  of  the  face  constitutes  the  pes  anse- 
rinus.  12.  The  auricularis  magnus  nerve,  one  of  the  ascending  branches  of  the  cer- 
vical plexus.  13.  The  occipitalis  minor,  ascending  along  the  posterior  border  of  the 
sterno-mastoid  muscle.  14.  The  superficial  and  deep  descending  branches  of  the  cer- 
vical plexus.  15.  The  spinal  accessory  nerve,  giving  off  a  branch  to  the  external  sur- 
face of  the  trapezius  muscle.  16.  The  occipitalis  major  nerve,  the  posterior  branch  of 
the  second  cervical  nerve. 


420  GLOSSO-PHARYNGEAL  NERVE. 

,    ^,  .-J     1     J  i  Anterior  auricular, 

In  the  parotid  eland,  >  *      •     i     • 

■  I  f^  °  <  AuncLilaris  magnus, 

(  Occipitalis  minor. 

Supra-orbital, 
Inlra-orbital, 
On  the  face  and  neck,  J  Temporo-malar, 
with  ]  Buccal, 

Mental, 
Superficialis  colli. 

8th  pair, — This  pair  consists  of  three  nerves,  the  glosso-pharyn- 
geal,  pneumogastric,  and  spinal  accessory. 

The  Glosso-pharyngeal  Nervb  arises  by  several  filaments  from 
the  respiratory  tract,  between  the  corpus  olivare  and  restiforme, 
and  escapes  from  the  skull  at  the  innermost  extremity  of  the  jugular 
foramen  through  a  distinct  opening  in  the  dura  mater,  lying  ante- 
riorly to  the  sheath  of  the  pneumogastric  and  spinal  accessory 
nerves,  and  internally  to  the  jugular  vein.  It  then  passes  for- 
wards between  the  jugular  vein  and  internal  carotid  artery  to 
the  stylo-pharyngeus  muscle,  and  descends  along  its  inferior  border 
to  the  hyo-glossus,  beneath  w^hich  it  passes  to  be  distributed  to  the 
mucous  membrane  of  the  base  of  the  tongue  and  fauces,  to  the 
mucous  glands  of  the  mouth,  and  to  the  tonsils.  While  situated 
in  the  jugular  fossa,  the  nerve  presents  two  gangliform  swellings, 
one  superior  (ganglion  jugulare  of  Miiller)  of  small  size,  and  in- 
volving only  the  posterior  fibres  of  the  nerve,  the  other  inferior, 
nearly  half  an  inch  below  the  preceding,  of  larger  size  and  occupy- 
ing the  whole  diameter  of  the  nerve,  the  ganglion  of  Andersch* 
(ganglion  petrosum). 

The  fibres  of  origin  of  this  nerve  may  be  traced  through  the  fas- 
ciculi of  the  corpus  restiforme  to  the  gray  substance  in  the  floor  of 
the  fourth  ventricle. 

The  Branches  of  the  glosso-pharyngeal  nerve  are — 

Communicating  branches  with  the  Facial, 

Pneumogastric, 
Spinal  accessory, 
Sympathetic. 

Tympanic, 

Muscular, 

Pharyngeal, 

Lingual, 

TonsilUtic. 

The  Branches  of  communication  proceed  from  the  ganglion  and 
from  the  upper  part  of  the  trunk  of  the  nerve,  and  are  common  to 

*  Charles  Samuel  Andersch.  "Tractatus  Anatomico-Physiologicus  de  Nervis  Cor- 
poris  Hutnani  Aliquibus,  1797." 


PNEUMOGASTRIC  NERVE.  421 

the  facial,  eighth  pair,  and  sympathetic  ;  they  form  a  complicated 
plexus  at  the  base  of  the  sknll. 

The  Tympanic  branch  (Jacobson's  nerve)  enters  a  small  bony 
canal  in  the  petrous  portion  of  the  temporal  bone,  and  divides  into 
six  branches,  which  are  distributed  upon  the  inner  wall  of  the  tym- 
panum, and  establish  important  communications  with  the  sympa- 
thetic and  fifth  pair  of  nerves.  The  branches  of  distribution  supply 
the  fenestra  rotunda,  fenestra  ovahs,  and  Eustachian  tube :  those  of 
communication  join  the  carotid  plexus,  the  petrosal  branch  of  the 
Vidian  nerve,  and  the  otic  ganglion. 

The  Muscular  branch  divides  into  filaments,  which  are  distributed 
to  the  stylo-pharyngeus  and  to  the  posterior  belly  of  the  digastricus 
and  stylo-hyoideus  muscle. 

The  Pharyngeai  branches  are  two  or  three  filaments  which  are 
distributed  to  the  pharynx  and  unite  with  the  pharyngeal  branches 
of  the  pneumogastric  and  of  the  sympathetic  nerve  to  form  the 
pharyngeal  plexus. 

The  Lingual  branches  enter  the  substance  of  the  tongue  beneath 
the  hyo-glossus  and  stylo-glossus  muscle,  and  are  distributed  to  the 
mucous  membrane  of  the  side  and  base  of  the  tongue,  and  to  the 
fauces. 

The  Tonsillitic  branches  proceed  from  the  glosso-pharyngeal 
nerve  near  to  its  termination ;  they  form  a  plexus  (circulus  tonsil- 
laris) around  the  base  of  the  tonsil,  from  which  numerous  filaments 
are  given  off  to  the  mucous  membrane  of  the  fauces  and  soft  palate, 
communicating  with  the  posterior  palatine  branches  of  Meckel's 
ganglion. 

The  Pneumogastric  Nerve  (vagus)  arises  by  numerous  filaments 
from  the  respiratory  tract  immediately  below  the  glosso-pharyngeal, 
and  passes  out  of  the  skull  through  the  inner  extremity  of  the 
jugular  foramen  in  a  distinct  canal  of  the  dura  mater.  While 
situated  in  this  canal  it  presents  a  small  rounded  ganglion;  and 
having  escaped  from  the  skull,  a  gangliform  swelling,  nearly  an  inch 
in  length,  and  surrounded  by  an  irregular  plexus  of  white  nerves, 
which  communicate  with  each  other,  with  the  other  divisions  of  the 
eighth  pair,  and  with  the  trunk  of  the  pneumogastric  below  the 
ganglion.  This  second,  or  pkziform  ganglion  (ganglion  of  the  su- 
perior laryngeal  branch,  of  Sir  Astley  Cooper),  is  situated,  at  first, 
behind  the  internal  carotid  artery,  and  then  between  that  vessel  and 
the  internal  jugular  vein.  The  pneumogastric  nerve  then  descends 
the  neck  within  the  sheath  of  the  carotid  vessels,  lying  behind  and 
between  the  artery  and  vein,  to  the  root  of  the  neck.  Here  the 
course  of  the  nerve  at  opposite  sides  becomes  different. 

The  Right  passes  between  the  subclavian  artery  and  vein  to  the 
posterior  mediastinum,  then  behind  the  root  of  the  lung  to  the  oeso- 
phagus, which  it  accompanies  to  the  stomach,  lying  on  its  posterior 
aspect. 

The  Left  enters  the  chest  parallel  with  the  left  subclavian  artery, 
crosses  the  arch  of  the  aorta,  and  descends  behind  the  root  of  the 

36 


422  PNEUMOGASTRIC  NKRVE. 

lung,  and  along  the  anterior  surface  of  the  oesophagus,  to  the 
stomach. 

The  fibres  of  origin  of  the  pneumogastric  nerve,  like  those  of  the 
glosso-pharyngeal,  may  be  traced  through  the  fasciculi  of  the 
corpus  restiforme  into  the  gray  substance  of  the  floor  of  the  fourth 
ventricle. 

The  Branches  of  the  pneumogastric  nerve  are  the  following : 

Communicating  branches  with  the  Facial, 

Glosso-pharyngeal, 
Spinal  accessory, 
Hypo-glossal, 
Sympathetic. 

Pharyngeal, 

Superior  laryngeal, 

Cardiac, 

Inferior  or  recurrent  laryngeal. 

Pulmonary  anterior. 

Pulmonary  posterior, 

CEsophageal, 

Gastric. 

The  Branches  of  communication  form  part  of  the  complicated 
plexus  at  the  base  of  the  skull.  The  branches  to  the  ganglion  of 
Andersch,  and  that  to  the  facial  nerve,  are  given  off"  by  the  superior 
ganglion  in  the  jugular  fossa ;  the  latter  passes  through  a  minute 
canal  in  the  petrous  bone,  to  the  lower  part  of  the  aqueductus 
Fallopii. 

The  Pharyngeal  nerve  arises  from  the  pneumogastric,  immedi- 
ately above  the  plexiform  ganglion,  and  descends  behind  the  internal 
carotid  artery  to  the  upper  border  of  the  middle  constrictor,  upon 
which  it  forms  the  pharyngeal  plexus  assisted  by  branches  from  the 
glosso-pharyngeal,  superior  laryngeal,  and  sympathetic.  The  pha- 
ryngeal plexus  is  distributed  to  the  muscles  and  mucous  membrane 
of  the  pharynx. 

The  Superior  laryngeal  nerve  arises  from  the  inferior  ganglion  of 
the  pneumogastric,  of  which  it  appears  to  be  almost  a  continuation: 
hence  the  ganglion  has  been  named  by  Sir  Astley  Cooper,  the  "gan- 
glion of  the  superior  laryngeal  branch^  The  nerve  descends  behind 
the  internal  carotid  artery  to  the  opening  in  the  thyro-hyoidean  mem- 
brane, through  which  it  passes  with  the  superior  laryngeal  artery, 
and  is  distributed  to  the  mucous  membrane  of  the  larynx,  commu- 
nicating on  the  arytenoid  muscle,  and  behind  the  cricoid  cartilage, 
with  the  recurrent  laryngeal  nerve.  Behind  the  internal  carotid  it 
gives  off  the  external  laryngeal  branch,  which  sends  a  branch  to 
the  pharyngeal  plexus,  and  then  descends  to  supply  the  inferior 
constrictor  and  crico-thyroid  muscles  and  thyroid  gland,  and  com- 
municates by  two  or  three  branches  with  the  recurrent  laryngeal 
and  sympathetic  nerve. 


pneumogastric  nerve. 


423 


Mr.  John  Hilton,  demonstrator  of  ana-  Fig.  151. 

tomy  in  Guy's  Hospital,  who  has  made 
some  able  dissections  of  the  nerves  of  the 
larynx,  of  which  we  refer  the  student  to  a  (\ 
masterly  description  in  the  2d  vol.  of  the  ^ 
Guy's  Hospital  Reports,  concludes  that  the 
superior  laryngeal  nerve  is  the  nerve  of 
sensation  to  the  larynx,  being  distributed 
solely  (with  the  exception  of  its  external 
laryngeal  branch)  to  the  mucous  mem- 
brane, cellular  tissue,  and  glands.  If  this 
fact  be  taken  in  connexion  with  the  obser- 
vations of  Sir  Astley  Cooper,  and  the  dis- 
sections of  the  origin  of  the  nerve  by  Mr. 
Edward  Cock,  we  shall  perceive  that, 
both  in  the  ganglionic  origin  of  the  nerve 
and  in  its  distribution,  we  have  striking 
evidence  of  its  sensitive  function.  The 
recurrent,  or  inferior  laryngeal  nerve,  is 
the  proper  motor  nerve,  and  is  distributed 
to  the  muscles  of  the  larynx. 

The  Cardiac  branches,  two  or  three  in 
number,  arise  from  the  pneumogastric  in 
the  lower  part  of  the  neck,  and  cross  the 
lower  part  of  the  common  carotid,  to  com- 
municate with  the  cardiac  branches  of  the 
sympathetic,  and  with  the  great  cardiac 
plexus. 

The  Recurrent  laryngeal,  or  inferior  la- 
ryngeal nerve,  curves  around  the  subcla- 
vian artery  on  the  right,  and  the  arch  of 
the  aorta  on  the  left  side.  It  ascends  in 
the  groove  between  the  trachea  and  oeso- 
phagus, and  piercing  the  lower  fibres  of 
the  inferior  constrictor  muscle  enters  the 
larynx  close  to  the  articulaiion  of  the  in- 
ferior cornu  of  the  thyroid  with  the  cri- 
coid cartilage.  It  is  distributed  to  all 
the  muscles  of  the  larynx,  with  the  exception  of  the  crico 
and  communicates  with  the  superior  laryngeal  nerve.     As  i 


thyroid, 
t  curves 


Fig.  151.  Origin  and  distribution  of  the  eighth  pair  of  nerves.  1,  3,  4.  The  me- 
dulla oblongata.  1.  Is  the  corpus  pyramidale  of  one  side.  3.  The  corpus  olivare.  4. 
The  corpus  resliforme.  2,  The  pons  Varolii.  5.  The  facial  nerve.  6.  Tlie  origin  of 
the  glosso-pharynoreal  nerve.  7.  The  ganglion  of  Andersch.  8.  The  trunk  of  the 
nerve.  9.  The  spinal  accessory  nerve.  JO.  The  ganglion  of  the  pneumogastric  nerve. 
11.  Its  plexiform  ganglion.  12.  Its  trunk.  13.  Its  pharyngeal  brancli  forming  the 
pharyngeal  plexus  (14),  assisted  by  a  branch  from  the  glosso-pliaryngcal  (8),  and  one 
from  the  superior  laryngeal  nerve  (15).  IC.  Cardiac  branches.  17.  Recurrent  laryn- 
geal brancli.  18.  Anterior  pulmonary  branches.  19.  Posterior  pulmonar}'  branches. 
20.  CEsophageal  plexus.  21.  Gastric  branches.  22.  Origin  of  the  spinal  accessory 
nerve.  23.  Its  branches  distributed  to  the  sterno-mastoid  muscle.  24.  Its  branches  to 
the  trapezius  muscle. 


424  SPINAL  ACCESSORY  NERVE. 

around  the  subclavian  artery  and  aorta  it  gives  branches  to  the 
heart  and  root  of  the  lungs;  and  as  it  ascends  the  neck  it  distributes 
filaments  to  the  cesophagns  and  trachea,  and  conamunicates  with 
the  external  laryngeal  nerve  and  sympathetic. 

The  Antftrior  pulm.onary  branches  are  distributed  upon  the  ante- 
rior aspect  of  the  root  of  the  lungs,  forming,  with  branches  from  the 
great  cardiac  plexus,  the  anterior  pulmonary  plexus. 

The  Pofiteri or  pulmonary  branches,  more  numerous  than  the  ante- 
rior, are  distributed  upon  the  posterior  aspect  of  the  root  of  the 
lungs,  and  are  joined  by  branches  from  the  great  cardiac  plexus, 
forming  the  posterior  pulmonary  plexus. 

Upon  the  oesophagus  the  two  nerves  divide  into  numerous  branches 
"which  communicate  with  each  other  and  constitute  the  esophageal 
plexus,  which  completely  surrounds  the  cylinder  of  the  oesophagus, 
and  accompanies  it  to  the  cardiac  orifice  of  the  stomach. 

The  Gastric  branches  are  the  terminal  filaments  of  the  two  pneu- 
mogastric  nerves  ;  they  are  spread  out  upon  the  anterior  and  poste- 
rior surfaces  of  the  stomach,  and  are  likewise  distributed  to  the 
omentum,  spleen,  pancreas,  liver,  and  gall-bladder,  and  communi- 
cate, particularly  the  right  nerve,  with  the  solar  plexus. 

The  Spinal  Accessory  Nerve  arises  by  several  filaments  from 
the  respiratory  tract,  as  low  down  as  the  fourth  or  fifth  cervical 
nerve,  and  ascends  behind  the  ligamentum  denticulatum,  and  between 
the  anterior  and  posterior  roots  of  the  spinal  nerves,  to  the  foramen 
lacerum  posterius.  It  communicates  in  its  course  with  the  posterior 
root  of  the  first  cervical  nerve,  and  soon  becomes  applied  against 
the  ganglion  of  the  pneumogastric,  and  enclosed  in  the  same  canal 
of  dura  mater.  In  the  jugular  fossa  it  divides  into  two  branches; 
the  smaller  joins  the  pneumogastric  immediately  below  the  superior 
ganglion,  and  contributes  to  the  formation  of  the  pharyngeal  nerve; 
while  the  larger  or  true  continuation  of  the  nerve  passes  backwards 
behind  the  internal  jugular  vein,  and  descends  obliquely  to  the  upper 
part  of  the  sterno-mastoid  muscle.  It  then  pierces  the  sterno-rnas- 
loid  and  passes  obliquely  across  the  neck,  communicating  with  the 
cervical  nerves,  and  is  distributed  to  the  trapezius.  The  spinal  ac- 
cessory sends  numerous  branches  to  the  sterno-mastoid  in  its  pas- 
sage through  that  muscle ;  its  branches  to  the  trapezius  may  be 
traced  to  the  lower  border  of  that  muscle. 

The  pneumogastric  and  spinal  accessory  nerves  together  resemble 
a  spinal  nerve,  the  former  representing  the  posterior  root  with  its 
ganglion,  and  the  latter  an  anterior  root. 

5ih  pair.  Trifacial  (trigeminus). — This  nerve  is  analogous  to  the 
spinal  nerves  in  its  origin  by  two  roots,  from  the  anterior  and  poste- 
rior columns  of  the  spinal  cord,  and  in  the  existence  of  a  ganglion 
on  the  posterior  root.  Hence  it  ranges  with  the  spinal  nerves,  and 
is  considered  as  the  cranial  spinal  nerve. 

It  arises*  by  two  roots  from  a  tract  of  yellowish  white  matter 

*  I  hnve  afloptcd  l?)e  orig-in  of  this  nerve,  given  by  Dr.  Alcocl<,  of  Dublin,  as  the 
result  of  his  dissections,  in  the  Cyclopaedia  of  Anatomy  and  Physiology.  Mr.  Mayo 
also  traces  the  anterior  root  of  the  nerve  to  a  similar  origin. 


FIFTH  PAIR TRIFACIAL. 


425 


situated  in  front  of  the  floor  of  the  fourth  ventricle  and  the  origin  of 
the  auditory  nerve,  and  behind  the  crus  cerebelli.     This  tract  divides 
inferiorly  into  tv^^o  fasciculi  which  may  be  traced  downwards  into 
the  spinal  cord,  one  being  continuous  with  the  fibres  of  the  anterior 
column,  the  other  with  the  posterior  column.     Proceeding  from  this 
origin  the  two  rootsof  the  nerve  pass  forward,  and  issue  from  the  brain 
upon  the  anterior  part  of  the  crus  cerebelli,  where  they  are  separated 
by  a  slight  interval.     The   ante- 
rior is  much  smaller  than  thepos-  Fig.  152. 
terior,  and  the  two  together  con- 
stitute the  fifth  nerve,  which  in 
this  situation  consists  of  seventy  to 
a  hundred  filaments  held  together 
by  pia   mater.     The  nerve  then 
passes  through  an  oval  opening  in 
the  border  of  the  tentorium,  near 
to  the  extremity  of  the  petrous 
bone,  and  spreads  out  into  a  large 
semilunar   ganglion — the    Casse- 
rian.     If  the  ganglion  be  turned 
over,  it  will  be  seen  that  the  ante- 
rior  root    lies   against  its  under 
surface  without  having  any  con- 
nexion with  it,  and   may  be  fol- 
lowed  onwards   to   the    inferior 
maxillary  nerve.     The  Casserian 
ganglion  divides  into  three  bran- 
ches,   the     ophthalmic,    superior 
maxillary,  and  inferior  maxillary. 
The    Ophthalmic  Nerve  is  a 
short  trunk,  being  not  more  than  three  quarters  of  an  inch  in  length  ; 
it  arises  from  the  upper  angle  of  the  Casserian  ganglion,  beneath 
the  dura  mater,  and  passes  forwards  through  the  outer  wall  of  the 
cavernous  sinus,  lying  externally  to  the  other  nerves :  it  divides 
into  three  branches.     Previously  to  its  division  it  receives  several 
filaments  from  the  carotid  plexus,  and  gives  off  a  small  recurrent 

Fig.  152.  A  view  of  the  distribution  of  the  trifacial  or  5th  pair. — 1.  Orbit.  2. 
Antrum  of  Highmore.  3.  Tongue.  4.  Lower  ma.xilla.  5.  Root  of  5th  pair  forming 
the  ganglion  of  Casser.  6.  \s\,hta.nch^  Ophlhalmic.  1.  2d  hTa.nch, Superior  maxillary. 
8.  3d  branch,  Inferior  maxillary.  9.  Frontal  branch,  dividing  into  external  and  in- 
ternal frontal  at  14.  10.  Lachrymal  branch,  dividing  before  entering  the  lachrymal 
gland.  11.  Nasal  branch.  Just  under  the  figure  is  the  long  root  of  the  lenticular  or 
ciliary  ganglion,  and  a  few  of  the  ciliary  nerves.  12.  Internal  nasal,  disappearing 
through  the  anterior  ethmoidal  foramen.  13.  External  nasal.  14.  External  and  in- 
ternal  frontal.  15.  Infra-orbitary  nerve.  16.  Posterior  dental  branches.  17.  Middle 
dental  branch.  18.  Anterior  dental  nerve.  19.  Terminating  branches  of  infra-orbital, 
called  labial  and  palpebral.  20.  Siibcutoneiis  mala  or  orbitar  branch.  21.  Pterj'goid 
or  recurrent,  from  Meckel's  ganglioii.  22.  Five  anterior  brandies  of  3d  of  5th,  being 
nerves  of  motion,  and  called  masseter,  temporal,  pterygoid  and  buccal.  2."^.  Lingual 
branch  joined  at  an  acute  angle  by  the  chorda  tympani.  24.  Inferior  dental  nerve 
terminating  in,  25.  Mental  branches.  26.  Superficial  temporal  nerve.  27.  Auricular 
branches.    28.  Mylo-hyoid  branch. 

36* 


426  BKATTCHES  OF  THE  OPHTHALMIC. 

nerve,  that  passes  backwards  with  the  recurrent  branch  of  the 
fourth  nerve  between  the  two  layers  of  the  tentorium  to  the  Uning 
membrane  of  the  lateral  sinus. 

The'Branches  of  the  ophthalmic  nerve  are,  the — 

Frontal, 
Lachrymal, 

Nasal." 

The  Frontal  nerve  mounts  above  the  levator  palpebree,  and  runs 
forward,  resting  upon  that  muscle,  to  the  supra-orbital  foramen, 
through  which  it  escapes  upon  the  forehead,  and  supplies  the  mus- 
cles and  integument  of  that  region. 

It  gives  off  one  small  branch,  the  supra-trochlear,  which  passes 
inwards  above  the  pulley  of  the  superior  oblique  muscle,  and  ascends 
along  the  middle  line  of  the  forehead,  distributing  filaments  to  the 
muscles  and  integument  at  the  inner  angle  of  the  eye  and  root  of  the 
nose. 

The  Lachrymal  nerve,  the  smallest  of  the  three  branches  of  the 
ophthalmic,  receives  a  filament  from  the  fourth  nerve  in  the  caver- 
nous sinus,  and  passes  outwards  along  the  upper  border  of  the  exter- 
nal rectus  muscle  to  the  lachrymal  gland,  where  it  divides  into  two 
branches.  The  superior  branch  passes  over  the  gland  and  through 
a  foramen  in  the  malar  bone,  and  is  distributed  upon  the  temple  and 
cheek,  communicating  with  the  temporo-malar  and  facial  nerves. 
The  inferior  branch  supplies  the  lower  surface  of  the  gland,  and  ter- 
minates in  the  integument  of  the  upper  lid,  communicating  with  the 
facial  nerve. 

The  Nasal  nerve  passes  forwards  between  the  two  heads  of  the 
external  rectus  muscle,  crosses  the  optic  nerve  in  company  with  the 
ophthalmic  artery,  and  enters  the  anterior  ethmoidal  foramen  imme- 
diately above  the  internal  rectus.  It  then  traverses  the  upper  part 
of  the  ethmoid  bone  to  the  cribriform  plate,  and  passes  downwards 
through  the  slit-like  opening  by  the  side  of  the  crista  galli  into  the 
nose,  where  it  divides  into  two  branches — an  internal  branch  supply- 
ing the  mucous  membrane,  near  the  anterior  openings  of  the  nares  ; 
and  an  external  branch  which  passes  between  the  fibro-cartilages, 
and  is  distributed  to  the  integument  at  the  extremity  of  the  nose. 

The  Branches  of  the  nasal  nerve  within  the  orbit  are,  the  gangli- 
onic, ciliary,  and  infra-trochlear ;  in  the  nose  it  gives  off  one  or  two 
filaments  to  the  anterior  ethmoidal  cells  and  frontal  sinus.  The 
ganglionic  branch  passes  obliquely  forwards  to  the  superior  angle  of 
the  ciliary  ganglion,  forming  its  superior  or  long  root.  The  ciliary 
branches  are  two  or  three  filaments  which  are  given  off  by  the  nasal 
as  it  crosses  the  optic  nerve.  They  pierce  the  posterior  part  of  the 
sclerotic,  and  pass  between  that  tunic  and  the  choroid  to  be  distri- 
buted to  the  iris.  The  infra-trochlear  is  given  off  just  as  the  nerve 
is  about  to  enter  the  anterior  ethmoidal  foramen.  It  passes  along 
the' superior  border  of  the  internal  rectus  to  the  inner  angle  of  the 
eye,  where  it  communicates  with  the  supra-trochlear  nerve,  and 


FIFTH  PAIR  OF  NERVES — BRANCHES.  427 

supplies  the  lachrymal  sac,  caruncula  lachrymalis,  conjunctiva,  and 
inner  angle  of  the  orbit. 

The  Superior  Maxillary  Nerve  proceeds  from  the  middle  of  the 
Casserian  ganglion;  it  passes  forwards  through  the  foramen  rolun- 
dum,  crosses  the  spheno-maxillary  fossa,  and  enters  the  canal  in  the 
floor  of  the  orbit,  along  which  it  runs  to  the  infra-orbital  foramen. 
Emerging  on  die  face,  beneath  the  levator  labii  superioris  muscle, 
it  divides  into  a  leash  of  branches,  which  are  distributed  to  the 
muscles  and  integument  of  the  cheek,  forming  a  plexus  with  the 
facial  nerve. 

The  Branches  of  the  superior  maxillary  nerve  are  divisible  into 
three  groups: — 1.  Those  which  are  given  off  in  the  spheno-maxil- 
lary fossa.  2.  Those  in  the  infra-orbital  canal;  and  3.  Those  on 
the  face.     They  may  be  thus  arranged: 

I  Orbital, 
Spheno-maxillary  fossa,   }  Two  from  Meckel's  ganglion,* 
(  Posterior  dental. 

r  /.        ,  .^  7  7  \  Middle  dental. 

Infra-orbital  canal,     .      j  ^^^^^.^^,  ^^^^^j^ 

^    ^,    ^  (  Muscular, 

On  the  face,       ...       In*. 

-'       '       ■  ^  Cutaneous. 

The  Orbital  branchf  enters  the  orbit  through  the  spheno-maxil- 
lary fissure,  and  divides  into  two  branches :  lachrymal, X  which 
ascends  along  the  outer  wall  of  the  orbit  to  the  lachrymal  gland, 
and  communicates  with  the  lachrymal  nerve :  temporo-malar,^  which 
passes  forwards  and  divides  into  two  branches :  one  piercing  the 
malar  bone,  is  distributed  to  the  integument  of  the  cheek,  communi- 
cating with  the  facial  nerve;  the  other  escaping  through  the  outer 
wall  of  the  orbit  supplies  the  temporal  muscle  and  integument  in 
the  temporal  region,  and  communicates  with  the  temporal,  anterior 
auricular,  and  facial  nerve. 

The  Tico  branches  from  Meckel's  ganglion  ascend  from  that 
body  to  join  the  nerve,  as  it  crosses  the  spheno-maxillary  fossa. 

The  Posterior  dental  branches  pass  through  small  foramina,  in 
the  posterior  surface  of  the  superior  maxillary  bone,  and  supply  the 
posterior  teeth.  « 

The  Middle  and  anterior  dental  branches  descend  to  the  teeth ; 
the  former  beneath  the  lining  membrane  of  the  antrum,  the  latter 
through  distinct  canals  in  the  walls  of  the  bone. 

The  Muscular  and  cutaneous  branches  are  the  terminating  fila- 

*  We  now  encounter  a  different  mode  of  describing  the  nerves  from  that  which  has 
been  so  long  in  use  ;  for  where  it  was  customary  to  describe  these  branches  as  branches 
of  the  fifth  pair  running  down  to  form  Meckel's  ganglion,  we  now  find  them  described 
as  running  up  to  join  the  fifth  pair.  This  arises  from  the  belief  now  general  that  these 
ganglia  form  a  part  of  the  great  sympatiietic,  and  the  student  will  find  tiieir  description 
under  that  iiead. — G. 

+  Nervus  subcutnneus  malm  of  other  anatomists. — G. 

t  The  malar  branch. — G.  §  The  temporal  branch. — G. 


428  GUSTATORY  NERVE. 

ments  of  the  nerve  ;  they  supply  the  muscles  and  integument  of  the 
cheek,  and  form  an  intricate  plexus  with  branches  of  the  facial 
nerve. 

The  Inferior  Maxillary  Nerve  proceeds  from  the  inferior  angle 
of  the  Casserian  ganglion:  it  is  the  largest  of  the  three  divisions  of 
the  fifth  nerve,  and  is  augmented  in  size  by  the  anterior  or  motor 
root,  which  passes  behind  the  ganglion,  and  unites  with  the  inferior 
maxillary  as  it  escapes  through  the  foramen  ovale.  Emerging  at 
the  foramen  ovale  the  nerve  divides  into  two  trunks,  external  and 
internal,  which  are  separated  from  each  other  by  the  external 
pterygoid  muscle. 

The  External  trunk,  into  which  may  be  traced  the  whole  of  the 
motor  root,  immediately  divides  into  five  branches,  which  are  dis- 
tributed to  the  muscles  of  the  temporo-maxillary  region  ;  they  are — 

The  Masseteric,  which  crosses  the  sigmoid  notch  with  the  mas- 
seteric artery  to  the  masseter  muscle.  It  sends  a  small  branch  to 
the  temporal  muscle,  and  a  filament  to  the  temporo-maxillary  arti- 
culation. 

Temporal;  two  branches  passing  between  the  upper  border  of 
the  external  pterygoid  muscle  and  the  temporal  bone  to  the  teui- 
poral  muscle.  Two  or  three  filaments  from  ihese  nerves  pierce  the 
temporal  fascia,  and  communicate  with  the  lachrymal,  temporo- 
malar,  auricular,  and  facial  nerve. 

Buccal;*  a  large  branch  which  pierces  the  fibres  of  the  external 
pterygoid,  to  reach  the  buccinator  muscle.  This  nerve  sends  fila- 
ments to  the  temporal  and  external  pterygoid  muscle,  to  the  mucous 
membrane  and  integument  of  the  cheek,  and  communicates  with  the 
facial  nerve. 

Internal  pterygoid;  a  long  and  slender  branch,  which  passes  in- 
wards to  the  internal  pterygoid  muscle.  This  nerve  is  remarkable 
from  its  connexion  with  the  otic  ganglion,  to  which  it  is  closely 
attached. 

The  Internal  trunk  divides  into  three  branches — 

Gustatory, 
Inferior  dental, 
Anterior  auricular. 

The  Gustatory  Nerve  descends  between  the  two  pterygoid 
muscles  to  the  side  of  the  tongue,  where  it  becomes  flattened,  and 
divides  into  numerous  filaments,  which  are  distributed  to  the  papilioe 
and  mucous  membrane. 

Relations. — It  lies  at  first  between  the  external  pterygoid  muscle 
and  the  pharynx,  next  between  the  two  pterygoid  muscles,  then 
between  the  internal  pterygoid  and  ramus  of  the  jaw,  and  between 
the  stylo-glossus  muscle  and  the  submaxillary  gland;  lastly,  it  runs 

•  The  name  buccal  is  usually  applied  to  the  central  branches  from  the  pes  anaerinua 
of  the  facial  nerve. — G, 


AURICULAR  NERVE — SPINAL  NERVES.  429 

along  the  side  of  the  tongue,  resting  upon  the  hyo-glossus  niuscle, 
and  covered  in  by  the  mylo-hyoideus  and  mucous  membrane. 

The  gustatory  nerve,  while  between  the  two  pterygoid  muscles, 
receives  a  branch  from  the  inferior  dental ;  lower  down  it  is  joined 
at  an  acute  angle  by  the  chorda  tympani,  which  passes  downwards 
in  the  sheath  of  the  gustatory  to  the  submaxillary  gland,  where  it 
unites  with  the  submaxillary  ganglion.  On  the  hyo-glossus  muscle 
some  branches  of  communication  are  sent  to  the  hypoglossal,  and 
in  the  course  of  the  nerve  several  small  branches  to  the  mucous 
membrane  of  the  fauces,  and  to  the  tonsils,  and  numerous  filaments 
to  the  submaxillary  gland. 

The  Inferior  Dental  Nerve  passes  downwards  with  the  inferior 
dental  artery,  at  first  between  the  two  pterygoid  muscles,  and  then 
between  the  internal  lateral  ligament  and  the  ramus  of  the  lower 
jaw,  to  the  dental  foramen.  It  then  runs  along  the  canal  in  the 
inferior  maxillary  bone,  distributing  branches  to  the  teeth,  and 
divides  into  two  branches,  incisive  and  mental.  The  incisive 
branch  passes  forwards  to  supply  the  incisive  teeth  :  and  the  mental 
branch  escapes  through  the  mental  foramen,  to  be  distributed  to  the 
muscles  and  integument  of  the  chin,  and  to  communicate  with  the 
facial  nerve. 

It  gives  off  but  one  branch,  the  mylo-hyoidean,  which  leaves  the 
nerve  just  as  it  is  about  to  enter  the  dental  foramen.  This  branch 
pierces  the  insertion  of  the  internal  lateral  ligament,  and  descends 
along  a  groove  in  the  bone  to  the  superior  surface  of  the  mylo- 
hyoid muscle,  to  which  it  is  distributed. 

The  Anterior  Auricular  Nerve  passes  directly  backwards  be- 
hind the  articulation  of  the  lower  jaw,  against  which  it  rests.  In 
this  situation  it  divides  into  two  branches,  which  reunite,  and  form 
a  kind  of  plexus.  From  the  plexus  two  branches  are  given  off — 
ascending  and  descending.  The  ascending  or  temporal  branch* 
sends  a  considerable  branch  of  communication  to  the  facial  nerve, 
and  then  ascends  in  front  of  the  ear  to  the  temporal  region,  upon 
which  it  is  distributed  in  company  with  the  branches  of  the  temporal 
artery.  In  its  course  it  sends  filaments  to  the  temporo-maxillary 
articulation,  to  the  pinna  and  meatus  of  the  ear,  and  to  the  integu- 
ment in  the  temporal  region.  It  communicates  on  the  temple  with 
branches  of  the  facial,  supra-orbital,  lachrymal,  and  temporo-malar 
nerve.  The  descending  branch  enters  the  parotid  gland,  to  which 
it  sends  numerous  branches;  it  communicates  with  the  inferior 
dental  and  auricularis  magnus  nerve,  and  supplies  the  external  ear 
and  the  temporo-maxillary  articulation. 

SPINAL  nerves. 

There  are  thirty-one  pairs  of  spinal  nerves,  each  arising  by  two 
roots,  an  anterior  or  motor  root,  and  a  posterior  or  sensitive  root. 
The  anterior  roots  arise  from  a  narrow  white  line  upon  the  ante- 

*  This  is  usually  called  the  superficial  temporal  nerve. — G, 


430  SPINAL  NERVES. 

rior  columns  of  the  spinal  cord,  and  gradually  approach  towards 
the  anterior  longitudinal  sulcus  as  they  descend. 

The  posterior  roots,  more  regular  than  the  anterior,  arise  from  a 
narrow  "gray  band  formed  by  the  internal  gray  substance  of  the 
cord.  They  are  larger,  and  the  filaments  of  the  origin  more  nume- 
rous than  those  of  the  anterior  roots.  A  ganglion  is  found  upon 
each  of  the  posterior  roots  in  the  intervertebral  foramina.  The 
first  cervical  nerve  forms  an  exception  to  these  characters.  Its 
posterior  root  is  smaller  than  the  anterior ;  there  is  frequently  no 
ganglion  upon  itj  and  it  often  joins  in  the  whole  or  in  part  with  the 
spinal  accessory  nerve. 

After  the  formation  of  the  ganglion  the  two  roots  unite,  and  con- 
stitute a  spinal  nerve,  which  escapes  through  the  intervertebral  fora- 
men, and  divides  into  an  anterior  branch,  for  the  supply  of  the 
front  half  of  the  body,  and  a  posterior  branch,  for  the  posterior  half. 

The  anterior  branches,  with  the  exception  of  the  two  first  cervical 
nerves,  are  larger  than  the  posterior ;  an  arrangement  which  is 
proportioned  to  the  larger  extent  of  surface  they  are  required  to 
supply. 

The  Spinal  nerves  are  divided  into — 

Cervical  ....  8  pairs 

^    Dorsal  ....  12 

Lumbar  ....  5 

Sacral  ....  6 

The  Cervical  nerves  pass  off  transversely  from  the  spinal  cord ; 
the  dorsal  are  oblique  in  their  direction ;  and  the  lumbar  vertical,  and 
form  the  large  assemblage  of  nerves  at  the  termination  of  the  cord 
called  Cauda  equina. 

The  Cervical  Nerves  increase  in  size  from  above  downwards ; 
the  first  (sub-occipital)  passes  out  of  the  spinal  canal  between  the 
occipital  bone  and  the  atlas ;  and  the  last,  between  the  last  cervical 
and  first  dorsal  vertebra.  Each  nerve,  at  its  escape  from  the  inter- 
vertebral foramen,  divides  into  an  anterior  and  a  posterior  branch. 
The  anterior  branches  of  the  four  upper  cervical  nerves  form  the 
cervical  'plexus ;  the  posterior  branches,  the  posterior  cervical  plexus. 

The  anterior  branches  of  the  four  inferior  cervical  together  with 
the  first  dorsal  form  the  brachial  plexus. 

Anterior  cervical  nerves. — The  Anterior  branch  of  the  first  cervical 
nerve  escapes  from  the  vertebral  canal  through  the  groove  upon  the 
posterior  arch  of  the  atlas  which  supports  the  vertebral  artery, 
beneath  which  it  lies.  It  then  descends  in  front  of  the  transverse 
process  of  the  atlas,  and  forms  a  loop  by  communicating  with  an 
ascending  branch  of  the  second  nerve. 

The  Anterior  branch  of  the  second  cervical  nerve  divides  into  three 
branches  at  its  exit  from  the  intervertebral  foramen  between  the 
atlas   and  axis,  viz.,  an  ascending  branch,  which  completes  the 


CERVICAL  BRANCHES.  431 

arch  of  communication  with  the  first  nerve ;  and  two  descending 
branches,  which  communicate  with  the  third  nerve. 

The  Anterior  branch  of  the  ikird  cervical  nerve,  double  the  size 
of  the  preceding,  divides  at  its  exit  from  the  intervertebral  foramen 
into  numerous  branches,  some  of  which  communicate  and  form 
loops  and  anastomoses  with  the  second,  and  others  with  the  fourth 
nerve. 

The  Anterior  branch  o^  the  fourth  cervical  nerve,  of  the  same  size 
with  the  preceding,  communicates  by  anastomoses  with  the  third, 
and  sends  a  small  branch  downwards  to  the  fifth  nerve.  Its  prin- 
cipal branches  pass  downwards  and  outwards  across  the  posterior 
triangle  of  the  neck,  towards  the  clavicle  and  acromion. 

The  Cervical  Plexus  is  constituted  by  the  loops  of  communica- 
tion, and  by  the  anastomosis  which  take  place  between  the  anterior 
branches  of  the  four  first  cervical  nerves.  The  plexus  rests  upon 
the  levator  anguli  scapulee,  posterior  scalenus,  and  splenius  muscle, 
and  is  covered  in  by  the  sterno-mastoid  and  platysma. 

The  branches  of  the  cervical  plexus  may  be  arranged  into  three 
groups,  superficial  ascending,  superficial  descending;  and  deep — 

C  Superficialis  colli, 

Ascending.  <  Auricularis  magnus, 

c!        c  •  1  ^  ( Occipitalis  minor. 

Superficial  <  r  \  •  \ 


Deep. 


T-v  7.  CAcromiales, 

Descending.         i  r^i     •     i 

°  I  Llaviculares. 

Communicating  branches, 
Muscular, 
Communicans  noni. 
Phrenic. 


The  Superficialis  colli  is  formed  by  communicating  branches  from 
the  second  and  third  cervical  nerves  ;  it  curves  around  the  posterior 
border  of  the  sterno-mastoid,  and  crosses  obliquely  behind  the  ex- 
ternal jugular  vein  to  the  anterior  border  of  that  muscle,  where 
it  divides  into  an  ascending  and  a  descending  branch  ;  ihe  descend- 
ing branch  is  distributed  to  the  integument  on  the  side  and  front  of 
the  neck  ;  the  ascending  branch  passes  upwards  to  the  submaxillary 
region,  and  divides  into  four  or  five  filaments,  some  of  which  pierce 
the  platysma  myoides  and  supply  the  integument  as  high  up  as  the 
chin  and  the  lower  part  of  the  face,  while  others  form  a  plexus  with 
the  descending  branches  of  the  facial  nerve  beneath  the  platysma. 
One  or  two  filaments  from  this  nerve  accompany  the  external 
jugular  vein. 

The  Auricularis  magnus  also  proceeds  from  the  second  and  third 
cervical  nerves  ;  it  curves  around  the  posterior  border  of  the  sterno- 
mastoid,  and  ascends  upon  that  muscle,  lying  parallel  with  the  ex- 
ternal jugular  vein,  to  the  parotid  gland,  where  it  divides  into  a 
superficial  and  deep  branch.  The  superficial  branch  is  distributed 
to  the  integument  over  the  parotid  gland,  and  to  the  anterior  surface 


432  CERVICAL  BRANCHES. 

of  the  external  ear.  The  deep  branch  pierces  the  parotid  gland 
and  crosses  the  mastoid  process,  where  it  divides  into  branches 
which  supply  the  posterior  part  of  the  pinna  and  the  integument  of 
the  side  of  the  head.  Previously  to  its  division  the  auricularis 
magnus  nerve  sends  off  several  facial  branches,  which  are  distri- 
buted to  the  cheek.  The  terminal  branches  of  this  nerve  commu- 
nicate with  branches  of  the  anterior  auricular,  the  facial,  and  the 
occipitalis  major  nerve. 

The  Occipitalis  minor  arises  from  the  second  cervical  nerve ;  it 
curves  around  the  posterior  border  of  the  sterno-mastoid  above  the 
preceding  and  ascends  upon  that  muscle,  parallel  with  its  posterior 
border,  to  the  lateral  and  posterior  side  of  the  head.  It  is  distributed 
to  the  integument  in  this  region. 

The  Acromiales  and  Claviculares  are  two  or  three  large  nerves 
which  descend  from  the  plexus  and  divide  into  numerous  branches 
which  pass  downwards  over  the  clavicle,  and  are  distributed  to  the 
integument  of  the  upper  and  anterior  part  of  the  chest  from  the 
sternum  to  the  shoulder. 

The  Communicating  branches  are  filaments  which  arise  from  the 
loop  between  the  first  and  second  cervical  nerve,  and  pass  inwards 
to  communicate  with  the  sympathetic,  the  pneumogastric,  and  the 
lingual  nerve.  The  three  first  cervical  nerves  send  branches  to  the 
first  cervical  ganglion ;  the  fourth  sends  a  branch  to  the  trunk  of 
the  sympathetic,  or  to  the  middle  cervical  ganglion.  From  the 
second  cervical  nerve  a  large  branch  is  given  off,  which  goes  to 
join  the  spinal  accessory  nerve. 

The  Muscular  branches  proceed  from  the  third  and  fourth  cer- 
vical nerves ;  they  are  distributed  to  the  trapezius,  levator  anguli 
scapulae,  and  rhomboidei  muscles.  From  the  second  cervical  nerve 
a  small  muscular  branch  is  sent  to  the  rectus  anticus  major. 

The  Communicans  noni  is  a  long  slender  branch  formed  by  fila- 
ments from  the  first,  second,  and  third  cervical  nerves ;  it  descends 
upon  the  outer  side  of  the  internal  jugular  vein,  and  forms  a  loop 
with  the  descendens  noni  over  the  sheath  of  the  carotid  vessels. 

The  Phrenic  nerve  is  formed  by  filaments  from  the  third,  fourth, 
and  fifth  cervical  nerves,  receiving  also  a  branch  from  the  sympa- 
thetic. It  descends  to  the  root  of  the  neck,  resting  upon  the  sca- 
.  lenus  anticus  muscle,  then  crosses  the  first  portion  of  the  subclavian 
artery,  and  enters  the  chest  between  it  and  the  subclavian  vein. 
Within  the  chest  it  passes  through  the  middle  mediastinum,  between 
the  pleura  and  pericardium  to  the  diaphragm,  to  which  it  is  dis- 
tributed, and  communicates  in  the  abdomen  with  the  phrenic  and 
solar  plexus,  and  on  the  right  side  with  the  hepatic  plexus.  The 
left  phrenic  nerve  is  rather  longer  than  the  right,  from  the  inclina- 
tion of  the  heart  to  the  left  side. 

Posterior  cervical  nerves. — The  posterior  division  of  the  first  cer- 
vical nerve  (sub-occipital),  larger  than  the  anterior,  escapes  from 
the  vertebral  canal  through  the  opening  for  the  vertebral  artery, 
lying  posteriorly  to  that  vessel,  and  emerges  into  the  triangular 


BRACHIAL  PLEXUS.  433 

space  formed  by  the  rectus  posticus  major,  obliquus  superior,  and 
obliquus  inferior.  It  is  distributed  to  the  recti  and  obliqui  muscles, 
and  sends  one  or  two  filaments  downwards  to  communicate  with 
the  second  cervical  nerve.  The  posterior  branch  of  the  second  cer- 
vical nerve  is  three  or  four  times  greater  than  the  anterior  branch, 
and  is  larger  than  the  other  posterior  cervical  nerves.  The  poste- 
rior brancii  of  the  third  cervical  nerve  is  smaller  than  the  preceding, 
but  larger  than  the  fourth  ;  and  the  other  posterior  cervical  nerves 
go  on  progressively  decreasing  to  the  seventh. 

Posterior  Cervical  Plexus. — This  plexus  is  constituted  by  the 
succession  of  anastomosing  loops  and  communications  which  pass 
between  the  posterior  branches  of  the  first,  second,  and  third  cer- 
vical nerTCs.  It  is  situated  between  the  complexus  and  semispinalis 
colli,  and  its  branches  are  the — 

Musculo-cutaneous, 
Occipitalis  major. 

The  Musculo-cutaneous  branches  pass  inwards  between  the  com- 
plexus and  semispinalis  colli  to  the  ligamentum  nuchas,  distributing 
muscular  filaments  in  their  course.  They  then  pierce  the  aponeu- 
rosis of  the  trapezius  and  become  subcutaneous,  sending  branches 
outwards  to  supply  the  integument  of  the  posterior  aspect  of  the 
neck,  and  upwards  to  the  posterior  region  of  the  scalp. 

The  Occipitalis  major  is  the  direct  continuation  of  the  second 
cervical  nerve;  it  ascends  obliquely  inwards,  between  the  obliquus 
inferior  and  complexus,  pierces  the  complexus  and  trapezius,  after 
passing  for  a  short  distance  between  them,  and  ascends  upon  the 
posterior  aspect  of  the  head  between  the  integument  and  occipito- 
frontalis,  in  company  with  the  occipital  artery.  The  occipitalis 
major  sends  numerous  branches  to  the  muscles  of  the  neck,  and  is 
distributed  to  the  integument  of  the  scalp,  as  far  forwards  as  the 
middle  of  the  vertex  of  the  head. 

The  Posterior  branches  of  the  fourth,  fifth,  sixth,  seventh,  and 
eighth  nerves  pass  inwards  between  the  muscles  of  the  back  in  the 
cervical  and  upper  part  of  the  dorsal  region,  and  reaching  the  sur- 
face near  to  the  middle  line  are  reflected  outwards  to  be  distributed 
to  the  integument.  The  fourth  and  fifth  are  nearly  transverse  in 
their  course,  and  lie  between  the  semispinalis  colli  and  complexus. 
The  sixth,  seventh,  and  eighth  are  directed  nearly  vertically  down- 
wards ;  they  pierce  the  aponeurosis  of  origin  of  the  splenius  and 
trapezius. 

BRACHIAL    PLEXUS. 

The  Brachial  or  axillary  plexus  of  nerves  is  formed  by  communi- 
cations between  the  anterior  branches  of  the  four  last  cervical  and 
first  dorsal  nerve.  These  nerves  are  all  similar  in  size,  and  tiieir 
mode  of  disposition  in  the  formation  of  the  plexus  is  the  following : 

37 


434 


BRACHIAL  PLEXUS — BRANCHES. 


the  fifth  and  sixth  nerves  unite  to  form  a  common  trunk,  which 
soon  divides  into  two   branches;  the  last  cervical  and  first  dorsal 
also  unite  immediately  upon  their  exit  from  the  intervertebral  fora- 
mina, and  the  common  trunk 
Fig.  153.  resulting    from    their   union 

after  a  short  course  also 
divides  into  two  branches ; 
the  seventh  nerve  passes  out- 
wards between  the  common 
trunks  of  the  two  preceding, 
and  opposite  the  clavicle 
divides  intoa  superiorbranch 
which  unites  with  the  infe- 
rior division  of  the  superior 
trunk,  and  an  inferior  branch 
which  communicates  with 
the  superior  division  of  the 
inferior  trunk ;  from  these 
divisions  and  communica- 
tions the  brachial  plexus  re- 
sults. The  brachial  plexus 
communicates  with  the  cer- 
vical plexus  by  means  of  a 
branch  sent  from  the  fourth 
to  the  fifth  nerve,  and  by  the 
inferior  branch  of  origin  of 
the  phrenic  nerve.  The 
plexus  is  broad  in  the  neck, 
narrow  as  it  descends  into 
the  axilla,  and  again  en- 
larges at  its  lower  part 
'  where  it  divides  into  its  six  terminal  branches. 

Relations. — The  brachial  plexus  is  in  relation  in  the  neck  with 
the  two  scaleni  muscles,  between  which  its  nerves  issue ;  lower  down 
it  is  placed  between  the  clavicle  and,  subclavius  muscle  above,  and 
the  first  rib  and  first  serration  of  the  serratus  magnus  muscle  below. 
In  the  axilla,  it  is  situated  at  first  to  the  outer  side  and  then  behind 
the  axillary  artery,  resting  by  its  outer  border  against  the  tendon 
of  the  subscapularis  muscle.  At  this  point  it  completely  surrounds 
the  artery  by  means  of  the  two  cords  which  are  sent  off"  to  form  the 
median  nerve. 

Its  Branches  may  be  arranged  into  two  groups,  humeral  and  de- 
scending,— 

Fig.  153.  A  view  of  the  brachial  plexus  of  nerves  and  branches  of  arm.     1,  1.  The 

scalenus  anticus  muscle,  in  front  of  wiiich  are  the  roots  of  the  plexus.     2,  2.  The 

median  nerve.     3.  The  ulnar  nerve.     4.  The  branch  to  the  biceps  muscle.     5.  The 
nerves  of  Wriaherg.     6.  The  phrenic  nerve  from  the  3d  and  4th  cervical. 


BRACHIAL  PLEXUS BRANCHES.  435 

Humeral  Branches.  Descending  Branches. 

Superior  muscular,  External  cutaneous, 

Short  thoracic,  Internal  cutaneous, 

Long  thoracic,  Lesser  internal  cutaneous, 

Supra-scapular,  Median, 

Subscapular,  Ulnar, 

Inferior  nnuscular.  Musculo-spiral, 

Circumflex. 

The  superior  Muscular  nerves  are  several  large  branches  which 
are  given  off  by  the  fifth  cervical  nerve  above  the  clavicle ;  they 
are — a  subclavian  branch  to  the  subclavius  muscle,  which  usually 
sends  a  communicating  filament  to  the  phrenic  nerve  ; — a  rhomboid 
branch  to  the  rhomboidei  muscles;  and  frequently  an  angular  branch 
to  the  levator  anguli  scapute. 

The  Short  thoracic  nerves  are  two  in  number;  they  arise  from  the 
brachial  plexus  at  a  point  parallel  with  the  clavicle,  and  are  divisible 
into  an  anterior  and  a  posterior  branch.  The  anterior  branch  passes 
forwards  between  the  subclavius  muscle  and  the  subclavian  vein, 
and  is  distributed  to  the  pectoralis  major  muscle,  entering  it  by  its 
costal  surface.  In  its  course  it  gives  off  a  branch  which  forms  a 
loop  of  communication  with  the  posterior  branch.  The  posterior 
branch  passes  forward  beneath  the  axillary  artery  and  unites  with 
the  communicating  branch  of  the  preceding  to  form  a  loop,  from 
which  numerous  branches  are  given  off"  to  the  pectoralis  major  and 
pectoralis  minor. 

The  Long  thoracic  nerve  (external  respiratory  of  Bell)  is  a  long 
and  remarkable  branch  arising  from  the  fourth  and  fifth  cervical 
nerves,  immediately  after  their  escape  from  the  intervertebral  fora- 
mina. It  passes  down  behind  the  plexus  and  axillary  vessels,  resting 
on  the  scalenus  posticus  muscle ;  it  then  descends  along  the  side  of 
the  chest  upon  the  serratus  magnus  muscle  to  its  lowest  serration. 
It  sends  numerous  filaments  to  this  muscle  in  its  course. 

The  Suprascapular  nerve  arises  above  the  clavicle  from  the  fifth 
cervical  nerve  and  descends  obliquely  outwards  to  the  supra-scapu- 
lar notch;  it  then  passes  through  the  notch,  crosses  the  supra-spinous 
fossa  beneath  the  supra-spinatus  muscle,  and  passing  in  front  of  the 
concave  margin  of  the  spine  of  the  scapula,  enters  the  infra-spinous 
fossa.  It  is  distributed  to  the  supra-spinatus  and  infra-spinatus 
muscle. 

The  Subscapular  nerves  are  three  or  four  in  number ;  of  which 
one  arises  from  the  brachial  plexus  above  the  clavicle,  and  the 
others  in  the  axilla.  They  are  distributed  to  the  subscapularis 
muscle. 

The  terminal  branches  of  the  plexus  are  arranged  in  the  follow- 
ing order:  the  external  cutaneous,  and  one  head  of  the  median  to 
the  outer  side  of  the  artery  ;  the  other  head  of  the  median,  internal 
cutaneous,  and  ulnar,  upon  its  inner  side;  and  the  circumflex  and 
musculo-spiral  behind. 


436  MEDIAN  NERVE BRANCHES. 

The  External  Cutaneous  Nerve  (musculo-cutaneous,  perforans 
Casserii)  arises  from  the  brachial  plexus  in  common  with  the  ex- 
ternal head  of  the  median  ;  it  pierces  the  coraco-brachialis  muscle, 
and  passes  between  the  biceps  and  brachialis  anticus,  to  the  outer 
side  of  the  bend  of  the  elbow,  where  it  perforates  the  fascia,  and 
divides  into  an  extei^nal  and  internal  branch. 

These  branches  pass  behind  the  median  cephalic  vein,  and  are 
distributed  to  the  integument  upon  the  outer  side  of  the  fore-arm  as 
far  as  the  wrist,  communicating  with  the  internal  cutaneous  and 
radial  nerves.  From  the  internal  division  at  the  lower  third  of  the 
fore-arm  a  branch  is  given  off  which  accompanies  the  radial  artery 
to  the  wrist  and  supplies  several  filaments  to  the  synovial  mem- 
branes of  the  wrist,  both  on  its  anterior  and  posterior  aspect. 

The  Branches  of  the  external  cutaneous  nerve  in  the  upper  arm 
are  distributed  to  the  coraco-brachialis,  biceps,  and  brachialis  anti- 
cus muscle. 

The  Internal  Cutaneous  Nerve  is  one  of  the  internal  and 
smallest  of  the  branches  of  the  axillary  plexus;  it  arises  from  the 
plexus  in  common  with  the  ulnar  and  internal  head  of  the  median, 
and  passes  down  the  inner  side  of  the  arm  in  company  with  the 
basilic  vein.  At  about  the  middle  of  the  arm  it  pierces  the  deep 
fascia  by  the  side  of  the  basilic  vein  and  divides  into  two  branches, 
anterior  and  posterior.  Each  of  these  branches  subdivides  into 
several  filaments,  which  are  distributed  to  the  integument  upon  the 
anterior  and  posterior  aspect  of  the  ulnar  border  of  the  fore-arm  as 
far  as  the  wrist.  At  the  bend  of  the  elbow  the  filaments  of  the  an- 
terior branch  pass  in  front  of  the  median  basilic  vein,  and  sometimes 
behind  that  vessel.  On  the  fore-arm  the  nervous  filaments  commu- 
nicate with  the  external  cutaneous  and  with  the  ulnar  nerve.    ' 

The  Lesser  Internal  Cutaneous  Nerve  or  nerve  of  Wrisherg  is 
very  irregular,  in  point  of  origin.  It  is  a  long  and  slender  nerve, 
and  usually  arises  from  the  common  trunk  of  the  last  cervical  and 
first  dorsal  nerve.  Passing  downwards  into  the  axillary  space  it 
communicates  with  the  external  branch  of  the  first  intercosto- 
humeral  nerve,  and  descends  upon  the  inner  side  of  the  internal 
cutaneous  nerve,  to  the  middle  of  the  posterior  aspect  of  the  upper 
arm,  where  it  pierces  the  fascia  and  is  distributed  to  the  integu- 
ment of  the  elbow,  communicating  with  the  filaments  of  the  internal 
cutaneous  and  spiral  cutaneous.  In  its  course  it  gives  off  two  or 
three  cutaneous  filaments  to  the  integument  of  the  inner  and  ante- 
rior aspect  of  the  upper  arm. 

The  Median  Nerve  has  received  its  name  from  taking  a  course 
along  the  middle  of  the  arm  to  the  palm  of  the  hand  ;  it  is,  there- 
fore, intermediate  in  position,  between  the  radial  and  ulnar  nerves. 
It  commences  by  two  heads,  which  embrace  the  axillary  artery  ; 
lies  at  first  to  the  outer  side  of  the  brachial  artery,  which  it  crosses 
at  its  middle;  and  descends  on  its  inner  side  to  the  bend  of  the 
elbow.  It  then  passes  between  the  two  heads  of  the  pronator  radii 
teres  and  flexor  sublimis  digitorum  muscles,  and  runs  down  the  fore- 


MEDIAN  NERVE — BRANCHES. 


437 


arm  between  the  flexor  sublimis  and  profundus,  and  beneath  the 
annular  hgament  into  the  palm  of  the  hand. 
The  branches  of  the  median  nerve  are, — 


Muscular, 

Anterior  interosseous, 


Superficial  palmar, 
Disital. 


Fig.  154. 


The  Muscular  branches  are  given  off  by  the  nerve  at  the  bend  of 
the  elbow;  they  are  distributed  to  all  the 
muscles  on  the  anterior  aspect  of  the  fore- 
arm, with  the  exception  of  the  flexor  carpi 
ulnaris,  and  to  the  periosteum.  The  branch 
to  the  pronator  radii  teres  sends  off"  reflected 
branches  to  the  elbow-joint. 

The  Anterior  interosseous  is  a  large  branch 
accompanying  the  anterior  interosseous  ar- 
tery, and  supplying  the  deep  layer  of  mus- 
cles in  the  fore-arm.  It  passes  beneath  the 
pronator  quadratus  muscle,  and  pierces  the 
interosseous  membrane  near  to  the  wrist. 
On  reaching  the  posterior  aspect  of  the 
wrist  it  joins  a  large  and  remarkable  gan- 
glion, which  gives  off"  a  number  of  branches 
for  the  supply  of  the  joint. 

The  Superficial  'palmar  branch  arises 
from  the  median  nerve  at  about  the  lower 
fourth  of  the  fore-arm  ;  it  crosses  the  an- 
nular ligament,  and  is  distributed  to  the  in- 
tegument over  the  ball  of  the  thumb  and  in 
the  palm  of  the  hand. 

The  median  nerve  at  its  termination  in 
the  palm  of  the  hand  is  very  considerably 
spread  out  and  flattened,  and  it  divides  into 
six  branches,  one  muscular  and  five  digital. 
The  muscular  branch  is  distributed  to  the 
muscles  of  the  ball  of  the  thumb.  The 
digital  branches  are  thus  arranged  : — two 
pass  outwards  to  the  thumb;  one  to  the 
radial  side  of  the  index  finger ;  one  subdivides  for  the  supply  of 
the  adjoining  sides  of  the  index  and  middle  fingers;  and  the  re- 
maining one,  for  the  supply  of  the  adjoining  sides  of  the  middle  and 
ring  fingers.  The  digital  nerves  in  their  course  along  the  fingers 
are  situated  to  the  inner  side  of  the  digital  arteries.  Opposite  the 
base  of  the  first  phalanx  each  nerve  gives  off"  a  dorsal  branch  which 
runs  along  the  border  of  the  dorsum  of  the  finger.  Near  the  ex- 
tremity of  the  finger  the  digital  nerve  divides  into  a  palmar  and  a 

Figf.  154.  Nerves  of  front  of  fore-arm.  1.  Median  nerve.  2.  Anterior  branch  of 
museulo-spiral  or  radial  nerve.  3.  Ulnar  nerve.  4.  Division  of  median  nerve  in  the 
palm  to  the  thnnib,  1st,  2d,  and  radial  side  of  3d  finger.  5,  Division  of  ulnar  nerve  to 
ulnar  side  of  3d  and  both  sides  of  4th  finger. 

37* 


438 


ULNAR  NERVE BRANCHES. 


dorsal  branch ;  the  former  supplying  the  sentient  extremity  of  the 
finger,  and  the  latter  the  structures  around  and  beneath  the  nail. 
The  digital  nerve  maintains  no  communication  with  its  fellow  of 
the  opposite  side. 

The  Ulnar  Nerve  is  somewhat  smaller  than  the  median,  behind 
which  it  lies,  gradually  diverging  from  it  in  its  course.  It  arises  from 
the  brachial  plexus  in  common  with  the  internal  head  of  the  median 
and  the  internal  cutaneous  nerve,  and  runs  down  the  inner  side  of 
the  arm,  to  the  groove  between  the  internal  condyle  and  olecranon, 
resting  upon  the  internal  head  of  the  triceps,  and  accompanied  by 
the  inferior  profunda  artery.  At  the  elbow 
it  is  superficial,  and  supported  by  the  inner 
condyle,  against  which  it  is  easily  com- 
pressed, giving  rise  to  the  thrilling  sensation 
along  the  inner  side  of  the  fore-arm  and  little 
finger,  ascribed  to  striking  the  "  funny  bone." 
It  then  passes  between  the  two  heads  of  the 
flexor  carpi  ulnaris  and  descends  along  the 
inner  side  of  the  fore-arm,  crosses  the  annular 
ligament,  and  divides  into  two  branches,  su- 
perficial and  deep  palmar.  At  the  commence- 
ment of  the  middle  third  of  the  fore-arm,  it 
becomes  applied  against  the  artery,  and  lies 
to  its  ulnar  side,  as  far  as  the  hand. 

The  Brandies  of  the  ulnar  nerve  are, — 

Muscular  in  the  upper  arm, 

Articular, 

Muscular  in  the  fore-arm. 

Anastomotic, 

Dorsal  branch, 

Superficial  palmar. 

Deep  palmar. 

The  Muscular  branches  in  the  upper  arm 
are  a  few  filaments  distributed  to  the  triceps. 
The   Articular  branches   are  several  fila- 
ments to  the  elbow-joint,  which  are  given  oflf 
from  the  nerve  as  it  lies  in  the  groove  be-* 
tween  the  inner  condyle  and  the  olecranon. 
The  Muscular  branches  in  the  fore-arm  are 
distributed  to  the  flexor   carpi  ulnaris  and  flexor  profundus  digi- 
torum  muscle. 

The  Anastomotic  branch  is  a  small  nerve  which  arises  from  the 
ulnar  at  about  the  middle  of  the  fore-arm,  and  divides  into  a  deep 
and  a  superficial  branch  ;  the  former  accompanies  the  ulnar  artery, 

FijT.  155.  A  view  of  the  nerves  on  the  dorsal  aspect  of  the  fore-arm  and  hand.  1,  1. 
The  ulnar  nerve.  2,  2.  The  posicrior  interosBcous  nerve.  3.  Termination  of  the 
Tiervus  cularievs  fivrnfri.  4.  The  dor  satis  carpi,  a  brancli  of  tiie  radial  nerve.  5,  5.  A 
back  view  of  the  digital  nerves.     6.  Dorsal  branch  of  the  ulnar  nerve. 


MUSCULO-SPIRAL  NERVE.  439 

and  the  latter  pierces  the  deep  fascia  and  comnnunicates  with  the 
internal  cutaneous  nerve. 

The  Dorsal  branch  passes  beneath  the  tendon  of  the  flexor  carpi 
ulnaris,  at  the  lower  third  of  the  fore-arm,  and  divides  into  branches 
which  supply  the  inlegument  and  two  fingers  and  a  half  on  the  pos- 
terior aspect  of  the  hand,  and  communicate  with  the  radial  nerve. 

The  Superficial  palmar  branch  divides  into  three  filaments, which 
are  distributed, — one  to  the  ulnar  side  of  the  little  finger,  o?z.e  to  the 
adjoining  borders  of  the  little  and  ring  fingers,  and  a  communica- 
ting branch  to  join  the  median  nerve. 

The  Deep  palmar  branch  passes  between  the  abductor  and  flexor 
minimi  digiti,  to  the  deep  palmar  arch,  supplying  the  muscles  of  the 
little  finger,  and  the  lumbricales  and  interossei  in  the  palm  of  the 
hand. 

The  MuscuLO-spiRAL  Nerve,  the  largest  branch  of  the  brachial 
plexus,  arises  from  the  posterior  part  of  the  plexus  by  a  common 
trunk  with  the  circumflex  nerve.  It  passes  downwards  from  its 
origin  in  front  of  the  tendons  of  the  latissimus  dorsi  and  teres  major 
muscle,  and  winds  around  the  humerus  in  the  spiral  groove,  accom- 
panied by  the  superior  profunda  artery,  to  the  space  between  the 
brachialis  anticus  and  supinator  longus  muscle,  and  thence  onwards 
to  the  bend  of  the  elbow,  where  it  divides  into  two  branches,  the 
posterior  interosseous  and  radial  nerve. 

The  Branches  of  the  musculo-spiral  nerve  are, — 

Muscular, 

Spiral  cutaneous, 

Radial, 

Posterior  interosseous. 

The  Muscular  branches  are  distributed  to  the  triceps,  to  the  supi- 
nator longus,  and  to  the  extensor  carpi  radialis  longior. 

The  Spiral  cutaneous  nerve  pierces  the  deep  fascia  immediately 
below  the  insertion  of  the  deltoid  muscle,  and  passes  down  the  outer 
side  of  the  fore-arm  as  far  as  the  wrist.  It  is  distributed  to  the  in- 
tegument. 

The  Radial  nerve  runs  along  the  radial  side  of  the  fore-arm  to 
the  commencement  of  its  lower  third ;  it  then  passes  beneath  the 
tendon  of  the  supinator  longus,  and  at  about  two  inches  above  the 
wrist-joint  divides  into  an  external  and  an  internal  branch.  The 
external  branch,  the  smaller  of  the  tv^'O,  is  distributed  to  the  outer 
border  of  the  hand  and  of  the  thumb.  The  internal  branch  crosses 
the  direction  of  the  extensor  tendons  of  the  thumb  and  divides  into 
several  filaments  for  the  supply  of  the  ulnar  border  of  the  thumb, 
the  radial  border  of  the  index  finger,  and  the  adjoining  borders  of 
the  index  and  middle  fingers.  It  communicates  on  the  back  of  the 
hand  with  the  dorsal  branch  of  the  ulnar  nerve. 

In  the  upper  third  of  the  fore-arm  the  radial  nerve  lies  beneath 
the  border  of  the  supinator  longus  muscle.  In  the  middle  third  it 
is  in  relation  with  the  radial  artery  lying  to  its  outer  side.     It  then 


440  DORSAL  NERVES. 

quits  the  artery,  and  passes  beneath  the  tendon  of  the  supinator 
longus,  to  reach  the  back  of  the  hand. 

The  Posterior  interosseous  nerve  separates  from  the  radial  at  the 
bend  of  the  elbow,  pierces  the  supinator  brevis  muscle,  and  emerges 
from  its  lower  border  on  the  posterior  aspect  of  the  fore-arm,  where 
it  divides  into  branches  which  supply  the  whole  of  the  muscles  on 
the  posterior  aspect  of  the  fore-arm.  One  branch,  longer  than  the 
rest,  descends  to  the  posterior  part  of  the  wrist,  and  forms  a  large 
gangliform  swelling  (the  common  character  of  nerves  which  sup- 
ply joints),  from  which  numerous  branches  are  distributed  to  the 
wrist-joint. 

The  Circumflex  Nerve  arises  from  the  posterior  part  of  the 
brachial  plexus  by  a  common  trunk  with  the  musculo-spiral  nerve. 
It  passes  downwards  over  the  border  of  the  subscapularis  muscle, 
winds  around  the  neck  of  the  humerus,  with  the  posterior  ciicumflex 
artery,  and  terminates  by  dividing  into  numerous  branches  which 
supply  the  deltoid  muscle. 

The  Branches  of  the  circumflex  nerve  are  muscular  and  cuta- 
neous. The  Muscular  branches  are  distributed  to  the  subscapu- 
laris, teres  minor,  teres  major,  latissimus  dorsi,  and  deltoid.  The 
cutaneous  branches  pierce  the  deltoid  muscle  and  are  distributed  to 
the  integument  of  the  shoulder.  One  of  these  cutaneous  branches, 
larger  than  the  rest,  winds  around  the  posterior  border  of  the  del- 
toid, and  divides  into  filaments  which  pass  in  a  radiating  direction 
across  the  shoulder  and  are  distributed  to  the  integument. 

DORSAL    NERVES. 

The  dorsal  nerves  are  twelve  in  number  on  each  side ;  the  first 
appears  between  the  first  and  second  dorsal  vertebra,  and  the  last 
between  the  twelfth  dorsal  and  first  lumbar.  Each  nerve,  as  soon 
as  it  has  escaped  from  the  intervertebral  foramen,  divides  into  two 
branches;  a  dorsal  branch  and  the  true  intercostal  nerve. 

The  Dorsal  branches  pass  directly  backwards  between  the  trans- 
verse processes  of  the  vertebrae,  lying  internally  to  the  anterior 
costo-transverse  ligament,  where  each  nerve  divides  into  a  muscu- 
lar and  a  miisculo-cutaneous  branch.  The  muscular  branch  enters 
the  substance  of  the  muscles  in  the  direction  of  a  line  corresponding 
with  the  interval  of  separation  between  the  longissimus  dorsi  and 
sacro-lumbalis,  and  is  distributed  to  the  muscles  of  the  back.  The 
muscuh-cutaneous  branch  passes  inwards,  crossing  the  semispinalis 
dorsi  to  the  spinous  processes  of  the  dorsal  vertebrae ;  it  then  pierces 
the  aponeurosis  of  origin  of  the  trapezius  and  latissimus  dorsi,  and 
divides  into  branches  which  are  inclined  outwards  beneath  the 
integument  to  which  they  are  distributed.  The  posterior  branch  of 
the  first  dorsal  nerve  resembles  in  its  mode  of  distribution  the  pos- 
terior branches  of  the  last  cervical.  The  posterior  branches  of  the 
four  last  dorsal  nerves  pass  obliquely  downwards  and  outwards  into 
the  substance  of  the  erector  spinas  in  the  situation  of  the  interspace 
between  the  sacro-lumbalis  and  longissimus  dorsi.     After  supplying 


DORSAL  NERVES.  441 

the  erector  spinse  and  communicating  freely  with  each  other  they 
approach  the  surface  along  the  outer  border  of  the  sacro-lumbalis, 
■where  they  pierce  the  aponeuroses  of  the  transversalis,  internal 
oblique,  serratus  posticus  inferior,  and  latissimus  dorsi  muscle,  and 
divide  into  internal  branches  which  supply  the  integument  upon  the 
middle  line  in  the  lumbar  region,  and  external  branches  which  are 
distributed  to  the  integument  upon  the  side  of  the  lumbar  and  in 
the  gluteal  region. 

The  Intercostal  nerves  receive  one  or  two  filaments  from  the 
adjoining  ganglia  of  the  sympathetic,  and  pass  forwards  in  the 
intercostal  space  with  the  intercostal  vessels,  lying  below  the  veins 
and  artery.  At  the  termination  of  the  intercostal  spaces  near  to 
the  sternum,  the  nerves  pierce  the  intercostal  and  pectoral  muscles, 
and  incline  downwards  and  outwards  to  be  distributed  to  the  inte- 
gument of  the  mamma  and  front  of  the  chest.  Those  which  are 
situated  between  the  false  ribs  pass  behind  the  costal  cartilages, 
and  between  the  transversalis  and  obliquus  internus  muscles;  and 
supply  the  rectus  and  the  integument  on  the  front  of  the  abdomen. 
The  first  and  last  dorsal  nerves  are  exceptions  to  this  distribution. 
The  anterior  branch  of  the  first  dorsal  nerve  divides  into  two 
branches;  a  smaller,  which  takes  its  course  along  the  under  sur- 
face of  the  first  rib  to  the  sternal  extremity  of  the  first  intercostal 
space;  and  a  larger,  which  crosses  obliquely  the  neck  of  the  first 
rib,  to  join  the  brachial  plexus.  The  last  dorsal  nerve,  next  in  size 
to  the  first,  sends  a  branch  of  communication  to  the  first  lumbar 
nerve,  to  assist  in  forming  the  lumbar  plexus. 

The  Branches  of  each  intercostal  nerve  are  a  muscular  twig  to 
the  intercostal  and  neighbouring  muscles,  and  a  cutaneous  branch 
which  is  given  oflT  at  about  the  middle  of  the  arch  of  the  rib.  The 
first  dorsal  nerve  has  no  cutaneous  branch.  The  cutaneous  branches 
of  the  second  and  third  intercostal  nerves  are  named,  from  their 
origin  and  distribution,  intercoslo-humeral. 

The  First  intercusto-humeral  nerve  is  of  large  size ;  it  pierces  the 
external  intercostal  muscle  of  the  second  intercostal  space,  and 
divides  into  an  internal  and  an  external  branch.  The  internal 
branch  is  distributed  to  the  integument  of  the  inner  side  of  the  arm. 
The  external  branch  communicates  with  the  nerve  of  Wrisberg, 
and  divides  into  filaments  which  supply  the  integument  upon  the 
inner  and  posterior  aspect  of  the  arm  as  far  as  the  elbow.  This 
nerve  sometimes  takes  the  place  of  the  nerve  of  Wrisberg. 

The  Second  Intercosto-humeral  nerve  is  much  smaller  than  the 
preceding;  it  emerges  from  the  external  intercostal  muscle  of  the 
third  intercostal  space  between  the  serrations  of  the  serratus  magnus 
muscle,  and  divides  into  filaments  which  are  distributed  to  the  inte- 
gument of  the  shoulder.  One  of  these  filaments  may  be  traced  in- 
wards to  the  integument  of  the  mamma. 

The  cutaneous  branches  of  the  fourth  and  jifh  intercostal  nerve 
send  twigs  to  the  integument  of  the  mammary  gland.  The  c^da- 
neous  branches  of  the  remaining  intercostal  nerves  reach  the  surface 


442 


LPMBAK  NERVES. 


between  the  serrations  of  the  serratus  magnus  muscle  above  and 
the  external  oblique  below,  and  each  nerve  divides  into  an  anterior 
and  a.  posterior  branch;  the  former  being  distributed  to  the  integu- 
ment of  the  antero-lateral,  and  the  latter  to  that  of  the  lateral  part 
of  the  trunk. 

The  cutaneous  branch  of  the  last  dorsal  nerve  is  remarkably  large; 
it  pierces  the  internal  and  external  oblique  muscles,  crosses  the  crest 
of  the  ilium,  and  is  distributed  to  the  integument  of  the  gluteal 
region. 

LUMBAR  NERVES. 

There  are  five  pairs  of  lumbar  nerves,  of  which  the  first  makes 

its  appearance  between  the 
Fig.  156.  first  and  second  lumbar  ver- 

tebra, and  the  last  between 
the  fifth  lumbar  and  the  base 
of  the  sacrum.  The  anterior 
branches  increase  in  size 
from  above  downwards,  and 
form  the  lumbar  plexus.  The 
posterior  branches  diminish 
in  size  from  above  down- 
wards ;  they  form  loops  of 
communication  with  each 
other,  and  are  distributed  to 
the  muscles  of  the  lumbar 
region,  and  to  the  integument 
over  the  sacrum  in  the  same 
manner  with  the  posterior 
branches  of  the  lower  dorsal 
nerves. 

The  lumbar  plexus  is  form- 
ed by  the  communications 
and  anastomoses  which  take 
place  between  the  anterior 
branch  of  the  last  dorsal  and 
of  the  five  lumbar  nerves. 
It  is  narrow  above  and  increases  in  breadth  inferiorly,  is  situated 
between  the  transverse  processes  of  the  lumbar  vertebrse  and  the 
psoas  magnus  muscle,  and  receives  filaments  of  communication 
from  the  lumbar  ganglia  of  the  sympathetic. 


Fig.  156.  A  view  of  the  lumbar  and  ischiatic  plexus  and  the  branches  of  the  former. 
A.  The  bodies  of  the  lumbar  vcrtebrce.  R.  The  psoas  magnus  muscle.  C.  The  iliacus 
intcrnufl  muscle.  D.  The  quadratus  lumborum  muscle.  E.  The  diaphragm.  F.  The 
three  broad  muscles  of  the  abdomen.  G.  The  sartorius.  1.  'I'he  lumbar  plexus.  2. 
The  ischiiitic  plexus.  3,  3.  Abdomino-crural  nerves.  4.  External  cutaneous  nerve 
(iriffuinocutaneous).  5,  G,  7.  Cutaneous  branches  from  (8).  The  anterior  crural  nerve, 
y.  The  genitocrural  nerve  or  spermaticua  externus.  10,  10.  The  lower  termination  of 
the  great  sympathetic. 


BRANCHES  OF  THE  LUMBAR  PLEXUS.  443 

The  Branches  of  the  lumbar  plexus  are  the 

MuscuIo-cutaneoLis, 

External-cutaneous, 

Genito-crural, 

Crural, 

Obturator, 

Lumbo-sacral. 

The  Musculo- cutaneous  nerves,  two  in  number,  superior  and  infe- 
rior, proceed  from  the  first  lumbar  nerve.  The  superior  musculo- 
cutaneous nerve  (ilio-scrotal)  passes  outwards  between  the  posterior 
fibres  of  the  psoas  magnus,  and  crosses  obliquely  the  quadratus  lum- 
borum  muscle  to  the  crest  of  the  ilium.  It  then  pierces  the  trans- 
versalis  muscle,  winds  along  the  crest  of  the  ilium  between  the 
transversalis  and  internal  oblique,  and  divides  into  two  branches, 
abdominal  and  scrotal.  The  abdominal  branch  is  continued  forwards 
parallel  with  the  last  intercostal  muscle  to  the  rectus  muscle,  to 
which  it  is  distributed,  sending  a  branch  forwards  to  the  integument 
of  the  abdomen.  The  scrotal  branch  opposite  the  anterior  superior 
spinous  process  of  the  ilium,  communicates  with  the  inferior  mus- 
culo-cutaneous  nerve,  and  escapes  at  the  external  abdominal  ring, 
with  the  spermatic  cord  in  the  male,  and  with  the  round  ligament 
in  the  female.  It  is  distributed  to  the  integument  of  the  front  of  the 
OS  pubis  and  of  the  groin,  to  the  scrotum  in  the  male  and  to  the 
greater  labium  in  the  female.  The  inferior  musculo-cutaneous  nerve 
also  arises  from  the  first  lumbar  nerve.  It  is  much  smaller  than 
the  preceding,  crosses  the  quadratus  lumborum  below  it,  and  takes 
the  same  course  along  the  crest  of  the  ilium.  It  terminates,  either 
by  communicating  with  the  superior  nerve,  or  by  escaping  with  it 
through  the  external  abdominal  ring  and  following  the  same  distri- 
bution. 

The  External  cutaneous  nerve  (inguino-cutaneous)  proceeds  from 
the  second  lumbar  nerve.  It  pierces  the  posterior  fibres  of  the  psoas 
muscle ;  and  crossing  the  iliacus  obliquely,  lying  beneath  the  iliac 
fascia  to  the  anterior  superior  spinous  process  of  the  ilium,  passes 
into  the  thigh  beneath  Poupart's  ligament.  It  then  pierces  the  fascia 
lata  at  about  two  inches  below  the  anterior  superior  spine  of  the 
ilium,  and  divides  into  two  branches,  anterior  and  posterior.  The 
posterior  branch  crosses  the  tensor  vaginae  femoris  muscle  to  the 
outer  and  posterior  side  of  the  thigh,  and  supplies  the  integument  in 
that  region.  The  anterior  nerve  divides  into  two  branches  which 
are  distributed  to  the  integument  upon  the  outer  border  of  the  thigh, 
and  to  the  articulation  of  the  knee. 

The  Genito-crural  proceeds  also  from  the  second  lumbar  nerve. 
It  traverses  the  psoas  magnus  from  behind  forwards,  and  runs 
down  on  the  anterior  surface  of  that  muscle  and  beneath  its  fascia 
to  near  Poupart's  ligament,  where  it  divides  into  a  genital  and  a 
crural  branch.  The  genital  branch  crosses  the  external  iliac  artery 
to  the  internal  abdominal  ring,  and  descends  along  the  spermatic 


444 


CRURAL  NERVE BRANCHES. 


Fig.  157. 


canal,  lying  behind  the  cord  to  the  scrotum,  where  it  divides  into 
branches  which  supply  the  spermatic  cord  and  cremaster  in  the  male, 
and  the  round  ligament  in  the  female.  At  the  internal  abdominal 
ring  this  nerve  sends  some  filaments  to  the  lower  border  of  the  in- 
ternal oblique  and  transversalis  muscle.  The  crural  branch  enters 
the  sheaih  of  the  femoral  vessels  in  front  of  the  femoral  artery.  It 
pierces  the  sheath  below  Poupart's  ligament,  and  is  distributed  to 
the  integument  of  the  anterior  aspect  of  the  thigh  as  far  as  its  middle. 
This  nerve  often  communicates  with  a  cutaneous  branch  of  the 
crural  nerve  in  the  thigh. 

The  Crural,  or  Femoral  Nerve,  is  the  largest  of  the  divisions  of 
the  lumbar  plexus;  it  is  formed  by  the  union 
of  the  branches  from  the  second,  third,  and 
fourth  lumbar  nerves,  and,  emerging  from 
beneath  the  psoas  muscle,  passes  downwards 
in  the  groove  between  it  and  the  iliacus,  and 
beneath  Poupart's  ligament  into  the  thigh, 
where  it  spreads  out  and  divides  into  nume- 
rous branches.  At  Poupart's  ligament  it  is 
separated  from  the  femoral  artery  by  the 
breadth  of  the  psoas  muscle,  which  at  this 
point  is  scarcely  more  than  half  an  inch  in 
diameter,  and  by  the  iliac  fascia,  beneath 
which  it  lies. 

Branches. — While  situated  within  the  pel- 
vis the  crural  nerve  gives  off  several  mus- 
cular branches  to  the  iliacus  and  psoas.  On 
emerging  from  beneath  Poupart's  ligament 
the  nerve  becomes  flattened  and  divides  into 
numerous  branches,  which  may  be  arranged 
into, — 

Cutaneous, 

Muscular, 

Branch  to  the  femoral  sheath, 

Short  saphenous  nerve. 

Long  saphenous  nerve. 

The  Cutaneous  branches  are  four  or  five  in 
number ;  they  pierce  the  fascia  lata  at  irregu- 
lar distances  below  Poupart's  ligament,  and 
are  distributed  to  the  integument  on  the  front 
and  inner  side  of  the  thigh,  constituting  the 
middle  and  internal  cutaneous  nerves.  Two 
of  these  nerves  pass  through  the  sartorius 
muscle  before  becoming  cutaneous. 

Fig.  157.  A  view  of  the  anterior  crural  nerve  and  branches.  ].  Place  of  emergence 
of  the  nerve  under  Pou|)art's  ligament.  2.  Division  of  the  nerve  into  branches.  3. 
Fer;ioral  artery.  4.  Femoral  vein.  5.  Branches  of  obturator  nerve.  6.  Nervua 
saphenus. 


SAPHENOUS  NERVE.  445 

The  Muscular  branches  are  several  large  tvings  which  are  distri- 
buted to  the  muscles  on  the  anterior  aspect  of  the  thigh.  Two  or 
three  of  these  branches  are  sent  to  the  sartorius ;  one  to  the  tensor 
vaginae  femoris,  one  to  the  rectus,  one  to  the  vastus  externus,  and 
one  of  very  large  size  to  the  vastus  internus  and  crurceus.  The 
latter  sends  off  a  cutaneous  branch  and  several  filaments  to  the 
periosteum  of  the  lower  part  of  the  femur,  and  to  the  articulation 
of  the  knee. 

The  Branch  to  the  femoral  sheath  is  a  small  nerve  which  passes 
inwards  to  the  sheath  of  the  femoral  vessels  at  the  upper  part  of  the 
thigh,  and  divides  into  several  filaments  which  surround  the  femoral 
and  profunda  vessels.  Two  of  these  filaments,  one  from  the  front, 
and  the  other  from  the  posterior  part  of  the  sheath,  unite  to  form  a 
small  nerve  which  escapes  from  the  saphenous  opening  and  passes 
downwards  with  the  saphenous  vein.  Other  filaments  are  distributed 
to  the  adductor  muscles,  and  communicate  with  the  internal  saphe- 
nous nerve. 

The  Short  saphenous  nerve  inclines  inwards  to  the  sheath  of  the 
femoral  vessels,  ^nd  divides  into  a  superficial  and  a  deep  branch. 
The  superficial  branch  passes  downwards  along  the  inner  border  of 
the  sartorius  muscle  to  the  lower  third  of  the  thigh,  it  then  joins  the 
internal  saphenous  vein  and  accompanies  that  vessel  to  the  knee- 
joint,  where  it  terminates  by  communicating  with  the  long  saphenous 
nerve.  The  deep  branch  descends  upon  the  outer  side  of  the  sheath 
of  the  femoral  vessels,  and  crosses  the  sheath  at  its  lower  part  to  a 
point  opposite  to  the  termination  of  the  femoral  artery,  where  it 
divides  into  several  filaments,  which  constitute  a  plexus  by  their 
communication  with  other  nerves.  One  of  these  filaments  commu- 
nicates with  the  descending  branch  of  the  obturator  nerve,  another 
with  the  long  saphenous  nerve,  and  two  or  three  are  distributed  to 
the  integument  upon  the  internal  and  posterior  aspect  of  the  thigh. 

The  Long  saphenous  nerve  inclines  inwards  to  the  sheath  of  the 
femoral  vessels,  and  entering  the  sheath  accompanies  the  femoral 
artery  to  the  tendinous  canal  formed  by  the  adductor  longus  and 
vastus  internus  muscles.  It  then  quits  the  artery,  and,  passing  be- 
tween the  tendons  of  the  sartorius  and  gracilis,  descends  along  the 
inner  side  of  the  leg  with  the  internal  saphenous  vein,  crosses  in 
front  of  the  inner  ankle,  and  is  distributed  to  the  integument  on  the 
inner  side  of  the  foot  as  far  as  the  great  toe. 

The  internal  saphenous  nerve  receives  at  its  upper  part  a  large 
branch  of  communication  from  the  obturator  nerve,  and  another  at 
the  inner  side  of  the  knee-joint.  In  its  course  it  gives  off  an  articu- 
lar branch  for  the  supply  of  the  synovial  membrane  of  the  knee- 
joint,  and  several  cutaneous  nerves ;  one  to  the  integument  of  the 
thigh ;  one,  of  large  size,  which  pierces  the  lower  part  of  the  sar- 
torius and  distributes  filaments  to  the  integument  of  the  knee,  and 
some  to  the  integument  of  the  leg,  of  the  inner  ankle,  and  of  the 
inner  side  of  the  foot. 

The  Obturator  nerve  is  formed  bv  a  branch  from  the  third,  and 

38' 


446  SACRAL  NERVES. 

another  from  the  fourth  lumbar  nerve.  It  passes  downwards  in  the 
fibres  of  the  psoas  muscle  through  the  angle  of  bifurcation  of  the 
common  iliac  vessels,  and  along  the  inner  border  of  the  brim  of  the 
pelvis,  to  the  obturator  foramen,  where  it  joins  the  obturator  artery. 
Having  escaped  from  the  pelvis  it  gives  off  two  small  branches  to 
the  obturator  externus  muscle,  and  divides  into  four  branches, — 
three  anterior,  which  pass  in  front  of  the  adductor  brevis,  supplying 
that  muscle,  the  pectineus,  the  adductor  longus,  and  the  gracilis; 
and  a  posterior  branch,  which  passes  downwards  behind  the  adductor 
brevis,  and  ramifies  in  the  adductor  magnus. 

From  the  branch  which  supplies  the  adductor  brevis,  a  communi- 
cating filament  passes  outwards  through  the  angle  of  bifurcation  of 
the  femoral  vessels  to  unite  with  the  long  saphenous  nerve.  From 
the  branch  to  the  adductor  longus  a  long  cutaneous  nerve  proceeds, 
which  issues  from  beneath  the  inferior  border  of  that  muscle,  sends 
filaments  of  communication  to  the  plexus  of  the  short  saphenous 
nerve,  and  descends  to  the  inner  side  of  the  knee,  where  it  pierces 
the  fascia  and  communicates  with  the  long  saphenous  nerve.  It  is 
distributed  to  the  integument  upon  the  inner  side  of  the  leg.  From 
the  posterior  branch  an  articular  branch  is  given  ofl^  which  pierces 
the  adductor  magnus  muscle,  accompanies  the  popliteal  artery,  and 
is  distributed  to  the  synovial  membrane  of  the  knee-joint  on  its  pos- 
terior aspect. 

The  Lumbosacral  nerve. — The  anterior  division  of  the  fifth  lum- 
bar nerve,  conjoined  with  a  branch  from  the  fourth,  constitutes  the 
lumbo-sacral  nerve,  which  descends  over  the  base  of  the  sacrum  into 
the  pelvis,  and  assists  in  forming  the  sacral  plexus. 

SACRAL     NERVES. 

There  are  six  pairs  of  sacral  nerves;  the  first  escapes  from  the 
vertebral  canal  through  the  first  sacral  foramina,  and  the  two  last 
between  the  sacrum  and  coccyx.  The  posterior  sacral  nerves 
are  very  small  and  diminish  in  size  from  above  downwards;  they 
communicate  with  each  other  immediately  after  their  escape  from 
the  posterior  sacral  foramina,  and  divide  into  branches  which  are 
distributed  to  the  muscles  and  integument  in  the  sacral  and  gluteal 
region.  The  anterior  sacral  nerves  diminish  in  size  from  above 
downwards;  the  ^rs^  is  of  large  size  and  unites  with  the  lumbo- 
sacral nerve;  the  second,  of  equal  size,  unues  with  the  preceding; 
the  third,  which  is  scarcely  one-fourth  the  size  of  the  second,  also 
joins  with  the  preceding  nerves  in  the  formation  of  the  sacral  plexus ; 
the  fourth  is  about  one-third  the  size  of  the  preceding  sacral  nerve; 
it  divides  into  several  branches,  one  of  which  is  sent  to  the  sacral 
plexus,  a  second  to  join  the  fifth  sacral  nerve,  a  third  to  the  viscera 
of  the  pelvis,  communicating  with  the  hypogastric  plexus,  and  a 
fourth  to  the  coccygeus  muscle,  and  to  the  integument  around  the 
anus.  The  fifth  anterior  sacral  nerve  presents  about  half  the  size  of 
the  fourth  ;  it  divides  into  two  branches,  one  of  which  communicates 


SACRAL  NERVES. 


447 


with  the  fourth,  the  other  with  the  sixth.     The  sixth  sacral  nerve  is 
exceedingly  small ;  it  gives  off  an  ascending 
filament  which  is  continuous  with  the  com-  Fig.  158. 

municating  branch  of  the  fifth;  and  a  de- 
scending filament  which  passes  downwards 
by  the  side  of  the  coccyx  and  traverses  the 
fibres  of  the  great  sacro-ischiatic  ligament  to 
be  distributed  to  the  gluteus  maximus  and  to 
the  integument.  All  the  anterior  sacral  nerves 
receive  branches  from  the  sacral  ganglia  of 
the  sympathetic  at  their  emergence  from  the 
sacrai  foramina. 

The  Sacral  plexus  is  formed  by  the  lumbo- 
sacral, and  by  the  anterior  branches  of  the 
four  upper  sacral  nerves.  The  plexus  is  tri- 
angular in  form,  the  base  corresponding  with 
the  whole  length  of  the  sacrum,  and  the  apex 
with  the  lower  part  of  the  great  ischiatic 
foramen.  It  is  in  relation  behind  with  the 
pyriformis  muscle,  and  in  front  with  the  pelvic 
fascia,  which  separates  it  from  the  branches 
of  the  internal  iliac  artery,  and  from  the  vis- 
cera of  the  pelvis. 

The  Branches  of  the  sacral  plexus  are 
divisible  into  the  internal  and  the  external;  they  may  be 
ranged : 


thus  ar- 


Internal. 
Visceral, 
Muscular. 


External. 
Muscular, 
Gluteal, 
Internal  pudic, 
Lesser  ischiatic, 
Greater  ischiatic. 


The  Visceral  nerves  are  three  or  four  large  branches  which  are 
derived  from  the  fourth  and  fifth  sacral  nerves :  they  ascend  upon 
the  side  of  the  rectum  and  bladder ;  in  the  female  upon  the  side  of 
the  rectum,  the  vagina  and  the  bladder;  and  interlace  with  the 
branches  of  the  hypogastric  plexus,  sending  in  their  course  numerous 
filaments  to  those  viscera. 

The  Muscular  branches  given  off  within  the  pelvis  are  one  or  two 
twigs  to  the  levator  ani ;  an  obturator  branch  which  curves  around 
the  spine  of  the  ischium  to  reach  the  internal  surface  of  the  obturator 
internus  muscle;  and  an  hoemorrhoidal  nerve,  which  descends  to 

Fig.  158.  A  view  of  the  branches  of  tlie  ischiatic  plexus  to  the  hip  and  hack  of  the 
thigh.  ],  1.  Posterior  sacral  nerves.  2.  Nervi  glutei.  3.  Tlie  internal  pudic  nerve, 
{nervus  pudendalis  longus  superior).  4.  The  lesser  ischiatic  nerve,  giving  off  the 
perineal  cutaneous  (pudendalis  longus  inferior,)  and  5.  The  ramus  femoralis  cutuneus 
posterior.  The  reference  to  the  great  ischiatic  has  been  omitted.  It  is  seen  to  the 
rififht  of  .3. 


448  LESSER  ISCHIATIC  NERVE. 

the  termination  of  the  rectum,  to  supply  the  sphincter  and  the  in- 
tegument. 

The  Muscular  branches  supplied  by  the  sacral  plexus  externally 
to  the  pelvis  are,  a  branch  to  the  pyramidalis;  a  branch  to  the 
gemellus  superior;  and  a  branch  of  moderate  size  which  descends 
between  the  gemelli  muscles  and  the  ischium,  and  is  distributed  to 
the  gemellus  inferior,  the  quadratus  femoris,  and  to  the  capsule  of 
the  hip-joint. 

The  Gluteal  nerve  is  a  branch  of  the  lumbo-sacral ;  it  passes  out 
of  the  pelvis  with  the  gluteal  artery,  through  the  great  sacro-ischiatic 
foramen,  and  divides  into  a  superior  and  an  inferior  branch.  The 
superior  branch  follows  the  direction  of  the  superior  curved  line  of 
the  ilium,  accompanying  the  deep  superior  branch  of  the  gluteal 
artery,  and  sending  filaments  to  the  gluteus  medius  and  minimus. 
The  inferior  passes  obliquely  downwards  and  forwards  between 
the  gluteus  medius  and  minimus,  distributing  numerous  filaments  to 
both,  and  terminates  in  the  tensor  vaginas  femoris  muscle. 

The  Internal  pudic  nerve  arises  from  the  lower  part  of  the  sacral 
plexus,  passes  out  of  the  pelvis  through  the  great  sacro-vschiatic 
foramen  below  the  pyriformis  muscle,  and  takes  the  course  of  the 
internal  pudic  artery.  While  situated  beneath  the  obturator  fascia 
it  lies  below  that  vessel  and  divides  into  a  superior  and  an  inferior 
branch.  The  superior  nerve  ascends  upon  the  posterior  surface  of 
the  ramus  of  the  ischium,  pierces  the  deep  perineal  fascia  and 
accompanies  the  arteria  dorsalis  penis  to  the  glans  to  which  it  is 
distributed.  At  the  root  of  the  penis  this  nerve  gives  off  a  cuta- 
neous branch  which  runs  along  the  side  of  the  organ,  and  with  its 
fellow  of  the  opposite  side  supplies  the  integument  of  the  upper  two- 
thirds  of  the  penis  and  of  the  prepuce.  The  inferior  or  perineal 
nerve  pursues  the  course  of  the  internal  pudic  artery  in  the  perineum 
and  sends  off  three  principal  branches, — 1,  an  external  perineal 
nerve  which  ascends  upon  the  outer  side  of  the  crus  penis,  and 
supplies  the  scrotum ;  2,  a  superficial  perineal  nerve  which  accom- 
panies the  artery  of  that  name  and  distributes  filaments  to  the  scro- 
tum, to  the  integument  of  the  under  part  of  the  penis  and  to  the 
prepuce;  3,  the  nerve  of  the  bulb,  which  sends  twigs  to  the  sphinc- 
ter ani,  to  the  transversus  perinei,  and  accelerator  urinse,  and  ter- 
minates by  ramifying  in  the  corpus  spongiosum. 

In  the  female,  the  internal  pudic  nerve  is  distributed  to  the  parts 
analogous  to  those  of  the  male.  The  superior  branch  supplies  the 
clitoris ;  and  the  inferior  the  parts  in  the  perineum  and  the  vulva. 

The  Lesser  ischiatic  nerve  passes  out  of  the  pelvis  through  the 
great  sacro-ischiatic  foramen  below  the  pyriformis  muscle,  and 
divides  into  muscular  and  cutaneous  branches.  The  muscular 
branches — inferior  gluteal — are  distributed  to  the  gluteus  maximus: 
some  ascending  in  the  substance  of  that  muscle  to  its  upper  border, 
and  others  descending.  The  cutaneous  branches  are  two  in  num- 
ber,— the  perineal  cutaneous  and  the  middle  posterior  cutaneous. 
The  perineal  cutaneous  nerve  (pudendalis  longus  inferior;  Soem.) 


THE  GREAT  ISCHIATIC  NERVE.  449 

curves  around  the  tuberosity  of  the  ischium  and  ascends  in  a  direc- 
tion parallel  to  the  ramus  of  the  ischium  and  os  pubis  to  the  scro- 
tum, where  it  communicates  with  the  superficial  perineal  nerve, 
and  divides  into  an  internal  and  an  external  branch.  The  internal 
branch  passing  down  upon  the  inner  side  of  the  testis  to  the  scro- 
tum ;  the  external  branch  to  its  outer  side,  and  both  terminating  in 
the  integument  of  the  under  border  of  the  penis.  The  middle  'poste- 
rior cutaneous  nerve  crosses  the  tuberosity  of  the  ischium,  and 
pierces  the  deep  fascia  at  the  lower  border  of  the  gluteus  maximus. 
It  then  passes  downwards  along  the  middle  of  the  posterior  aspect 
of  the  thigh,  and  of  the  popliteal  region,  and  is  distributed  to  the 
integument  as  far  as  the  middle  of  the  calf  of  the  leg.  In  its  course 
the  nerve  gives  off  several  cutaneous  branches  to  the  integument 
upon  the  inner  and  outer  side  of  the  thigh,  and  in  the  popliteal 
region  a  communicating  branch  which  pierces  the  fascia  of  the  leg 
and  unites  with  the  external  saphenous  nerve. 

The  Great  Ischiatic  Nerve  is  the  largest  nervous  cord  in  the 
body ;  it  is  formed  by  the  sacral  plexus,  or  rather  it  is  a  prolonga- 
tion of  the  plexus,  and  at  its  exit  from  the  great  sacro-ischiatic 
foramen  beneath  the  pyriformis  muscle  measures  three  quarters  of 
an  inch  in  breadth.  It  descends  through  the  middle  of  the  space 
between  the  trochanter  major  and  tuberosity  of  the  ischium,  and 
along  the  posterior  part  of  the  thigh  to  about  its  lower  third,  where 
it  divides  into  two  large  terminal  branches,  popliteal  and  peroneal. 
This  division  sometimes  takes  place  at  the  plexus,  and  the  two 
nerves  descend  together  side  by  side ;  occasionally  they  are  sepa- 
rated at  their  commencement  by  a  part  or  the  whole  of  the  pyri- 
formis muscle.  The  nerve  in  its  course  dovv^n  the  thigh  rests  upon 
the  gemellus  superior,  tendon  of  the  obturator  internus,  gemellus 
inferior,  quadratus  femoris,  and  adductor  magnus  muscle,  and  is 
covered  in  by  the  gluteus  maximus,  and  by  the  biceps  and  semiten- 
dinosus  muscle. 

The  Branches  of  the  great  ischiatic  nerve,  previously  to  its  divi- 
sion, are  muscular  and  articular.  The  muscular  branches  are 
given  off  from  the  upper  part  of  the  nerve,  and  supply  the  biceps, 
the  semi-tendinosus,  the  semi-membranosus,  and  the  adductor  mag- 
nus. The  articular  branch  descends  to  the  upper  part  of  the  exter- 
nal condyle  of  the  femur,  and  divides  into  filaments  which  are 
distributed  to  the  fibrous  capsule  and  to  the  synovial  membrane  of 
the  knee-joint. 

The  Popliteal  Nerve  passes  through  the  middle  of  the  popliteal 
space,  from  the  division  of  the  great  ischiatic  nerve  to  the  lower 
border  of  the  popliteus  muscle,  where  it  passes  with  the  artery 
beneath  the  arch  of  the  soleus,  and  becomes  the  posterior  tibial 
nerve.  It  is  superficial  in  the  whole  of  its  course,  and  lies  exter- 
nally to  the  vein  and  artery. 

The  Brandies  of  the  popliteal  nerve  are  muscular  or  sural  and 
articular,  and  a  cutaneous  branch,  the  communicans  y)oplitei. 

The  Muscular  branches,  of  considerable  size,  and  four  or  five  in 

38* 


450 


POSTERIOR  TIBIAL  NERVE. 


number,  are  distributed  to  the  two  heads  of  the  gastrocnemius,  to 
the  sole  us,  to  the  plantaris,  and  to  the  pophteus. 


Fi^.  159. 


Fiff.  160. 


The  Articular  nerve  pierces  the  ligamentum  posticum  Winslowi, 
and  supphes  the  interior  of  the  knee-joint.  It  usually  sends  a  twig  to 
the  popliteus  muscle. 

The  Communicans  popIUei  is  a  large  nerve  which  arises  from 
the  popliteal  at  about  the  middle  of  its  course,  and  descends  between 
the  two  heads  of  the  gastrocnemius,  and  along  the  groove  formed 
by  the  two  bellies  of  that  muscle;  at  a  variable  distance  below 
the  articulation  of  the  knee  it  receives  a  large  branch,  the  commu- 
nicans peronei,  from  the  peroneal  nerve,  and  the  two  together  con- 
stitute the  external  saphenous  nerve. 

The  External  saphenous  nerve  pierces  the  deep  fascia  below  the 

Fig.  159.  A  viow  of  some  of  the  branches  of  the  popliteal  nerve.  1.  The  popliteal 
nerve.  2,  3.  The  terminations  of  the  ramus  femoralis  cutaneiis  posterior.  4,  5.  The 
saphenous  nerve.     6,  6.  The  external  saphenous  or  communicans  tibial. 

Fig.  160.  A  view  of  the  posterior  tibial  nerve  in  the  back  of  tiie  leg.  1  and  2,  indi- 
cate it3  course,  the  upper  part  of  the  peroneal  nerve  being  seen  to  the  right. 


POSTERIOR  TIBIAL  NERVE. 


451 


Fig.  161. 


fleshy  part  of  the  gastrocnemius  muscle,  and  continues  its  course 
down  the  leg,  lying  along  the  outer  border  of  the  tendo  Achillis  and 
by  the  side  of  the  external  saphenous  vein,  which  it  accompanies 
to  the  foot.  At  the  lower  part  of  the  leg  it  winds  around  the  outer 
malleolus,  and  is  distributed  to  the  outer  side  of  the  foot  and  of  the 
little  toe,  communicating  with  the  external  peroneal  cutaneous  nerve, 
and  sending  numerous  filaments  to  the  integument  of  the  heel  and  of 
the  sole  of  the  foot. 

The  Posterior  Tibial  Nerve  is  continued  along  the  posterior 
aspect  of  the  leg  from  the  lower  border  of  the 
popliteus  muscle  to  the  posterior  part  of  the 
inner  ankle,  where  it  divides  into  the  internal 
and  external  plantar  nerve.  In  the  upper  part 
of  its  course  it  lies  to  the  outer  side  of  the 
posterior  tibial  artery;  it  then  becomes  placed 
superficially  to  that  vessel,  and  at  the  ankle 
is  again  situated  to  its  outer  side ;  in  the 
lower  third  of  the  leg  it  lies  parallel  with  the 
inner  border  of  the  tendo  Achillis. 

The  Branches  of  the  posterior  tibial  nerve 
are  three  or  four  muscular  twigs  to  the  deep 
muscles  of  the  posterior  aspect  of  the  leg ; 
the  branch  to  the  flexor  longus  poUicis  accom- 
panies the  fibular  artery ;  one  or  two  fila- 
ments which  entwine  around  the  artery  and 
then  terminate  in  the  integument;*  and  some 
cutaneous  branches  which  pass  downwards 
upon  the  inner  side  of  the  os  calcis  and  are 
distributed  to  the  integument  of  the  heel. 

The  Internal  plantar  nerve,  larger  than 
the  external,  crosses  the  posterior  tibial  ves- 
sels to  enter  the  sole  of  the  foot,  where  it  lies  in 
the  interspace  between  the  abductor  pollicis  and  flexor  brevis  digi- 
torum  ;  it  then  enters  the  sheath  of  the  latter  muscle,  and  divides 
opposite  the  bases  of  the  metatarsal  bones  into  three  digital  branches ; 
one  to  supply  the  adjoining  sides  of  the  great  and  second  toe ;  the 
second  to  the  adjoining  sides  of  the  second  and  third  toe ;  and  the 
third  to  the  third  and  fourth  toes.  The  distribution  is  precisely 
similar  to  that  of  the  digital  branches  of  the  median  nerve. 

In  its  course  the  internal  plantar  nerve  gives  oW cutaneous  branches 
to  the  integument  of  the  inner  side  and  sole  of  the  foot ;  muscular 

Fig.  161.  A  view  of  the  termination  of  the  posterior  tibial  nerve  in  the  sole  of  the 
foot.  1.  Inside  of  the  foot.  2.  Outer  side.  3.  Heel.  4.  Internal  plantar  nerve.  5. 
External  plantar  nerve.  6.  Branch  to  flexor  brevis.  7.  Branch  to  outside  of  little  toe. 
8.  Branch  to  space  between  4th  and  5th  toes.  9,  9,  9.  Digital  branches  to  remaining 
spaces.     10.  Branch  to  internal  side  of  great  toe. 

*  It  is  extremely  interesting  in  a  physiological  point  of  view,  to  observe  the  mode  of 
distribution  of  these  filaments.  I  have  traced  them  in  relation  with  several,  and  I  have 
no  doubt  that  they  exist  in  connexion  with  all  the  superficial  arteries.  They  seem  to 
be  the  direct  monitors  to  the  artery  of  the  presence  or  approach  of  danger. 


453 


PERONEAL  NERVE. 


Fia.  165. 


branches  to  the  muscles  forming  the  inner  and  middle  group  of  the 
sole;  a  digital  branch,  to  the  inner  border  of  the  great  toe;  and 
articular  branches  to  the  articulations  of  the  tarsal  and  metatarsal 
bones.    - 

The  External  plantar  nerve,  the  smaller  of  the  two,  follows  the 
course  of  the  external  plantar  artery  to  the  outer  border  of  the 
musculus  accessorius,  beneath  which  it  sends  sev^eral  large  mus- 
cular branches  to  supply  the  abductor  pollicis  and  the  articulations 
of  the  tarsal  and  metatarsal  bones.  It  then  gives  branches  to  the 
integument  of  the  outer  border  and  sole  of  the  foot,  and  sends  for- 
ward two  digital  branches  to  supply  the  little  toe  and  one  half  the 
next. 

The  Peroneal  Nerve  is  one  half  smaller  than  the  popliteal ;  it 
passes  downwards  by  the  side  of  the  tendon  of 
the  biceps,  crossing  the  inner  head  of  the  gas- 
trocnemius and  the  origin  of  the  soleus,  to  the 
neck  of  the  fibula,  where  it  pierces  the  origin  of 
the  peroneus  longus  muscle,  and  divides  into  two 
branches,  the  anterior  tibial  and  musculo-cuta- 
neous. 
I  Hi  The  Branches  of  the  peroneal  nerve  previously 
to  its  division  are,  the  communicans  peronei, 
cutaneous,  and  muscular.  The  communicans 
peronei,  much  smaller  than  the  communicans 
poplitei,  crosses  the  external  head  of  the  gas- 
trocnemius to  the  middle  of  the  leg.  It  there 
sends  a  large  branch  to  join  the  communicans 
poplitei  and  constitute  the  external  saphenous 
nerve,  and  descends  very  much  reduced  in  size 
by  the  side  of  the  external  saphenous  vein  to  the 
side  of  the  external  ankle,  to  which  and  to  the 
integument  of  the  heel  it  distributes  filaments. 
The  cutaneous  branch  descends  in  the  integu- 
ment upon  the  outer  side  of  the  leg,  in  which  it 
ramifies.  The  muscular  branches  proceed  from 
near  the  termination  of  the  peroneal  nerve  ;  they 
are  distributed  to  the  upper  part  of  the  tibialis 
anticus. 

The  Anterior  tibial  nerve  commences  at  the 
bifurcation  of  the  peroneal,  upon  the  head  of  the 
fibula,  and  passes  beneath  the  upper  part  of  the 
extensor  longus  digitorum,  to  reach  the  outer 
side  of  the  anterior  tibial  artery,  just  as  that  vessel 
has  emerged  through  the  opening  in  the  interos- 
seous membrane.  It  descends  the  anterior  aspect 
of  the  leg  with  the  artery ;  lying  at  first  to  its  outer  side,  and  then 


Fijr.  162.  A  view  of  the  anterior  tibial  nerve.     1.  The  peroneal  nerve.     2,3.  The 
anterior  tibial  nerve  accompanying  the  artery  of  the  same  name. 


SYMPATHETIC  SYSTEM.  453 

in  front  of  it,  and  near  the  ankle  becomes  again  placed  to  its  outer 
side.  Reaching  the  ankle  it  passes  beneath  the  annular  ligament; 
it  accompanies  the  dorsalis  pedis  artery,  supplies  the  adjoining  sides 
of  the  great  and  second  toes,  and  communicates  with  the  internal 
peroneal  cutaneous  nerve. 

The  Branches  given  off  by  the  anterior  tibial  nerve  are,  muscular 
to  the  muscles  in  its  course,  and  on  the  foot  a  tarsal  branch,  which 
passes  beneath  the  extensor  brevis  digitorum,  and  distributes  fila- 
ments to  the  interossei  muscles  and  to  the  articulations  of  the  tarsus 
and  metatarsus. 

The  Muscuh-cutaneous  nerve  passes  downwards  in  the  direction 
of  the  fibula,  in  the  substance  of  the  peroneus  longus  ;  it  then  passes 
forwards  to  get  between  the  peroneus  longus  and  brevis,  and  at  the 
lower  third  of  the  leg  pierces  the  deep  fascia,  and  divides  into  two 
peroneal  cutaneous  branches.  In  its  course  it  gives  off  several 
branches  to  the  peronei  muscles. 

The  Peroneal  cutaneous  nerves  pass  in  front  of  the  ankle-joint, 
and  are  distributed  to  the  integument  of  the  foot  and  of  the  toes; 
the  external  supplying  three  toes  and  a  half,  and  the  internal  one 
and  a  half  They  communicate  with  the  saphenous  and  anterior 
tibial  nerve.  The  external  saphenous  nerve  frequently  supplies  the 
fifth  toe  and  the  adjoining  side  of  the  fourth. 

SYMPATHETIC   SYSTEM. 

The  Sympathetic  system  consists  of  a  series  of  ganglia,  extending 
along  each  side  of  the  vertebral  column  from  the  head  to  the  coccyx, 
communicating  with  all  the  other  nerves  of  the  body,  and  distribu- 
ting branches  to  all  the  internal  organs  and  viscera. 

It  communicates  with  the  other  nerves  immediately  at  their  exit 
from  the  cranium  and  vertebral  canal.  The  fourth  and  sixth  nerves, 
however,  form  an  exception  to  this  rule ;  for  with  these  it  unites  in 
the  cavernous  sinus ;  and  with  the  olfactory,  optic,  and  auditory,  at 
their  ultimate  expansions. 

The  branches  of  distribution  accompany  the  arteries  which  supply 
the  different  organs,  and  form  communications  around  them,  which 
are  called  -plexuses,  and  take  the  name  of  the  artery  with  w^hich 
they  are  associated  :  thus  we  have  the  mesenteric  plexus,  hepatic 
plexus,  splenic  plexus,  &c.  All  the  internal  organs  of  the  head, 
neck,  and  trunk  are  supplied  with  branches  from  the  sympathetic, 
and  some  of  them  exclusiv^ely;  hence  it  is  considered  a  nerve  of 
organic  life. 

It  is  called  the  ganglionic  nerve  from  the  circumstance  of  being 
formed  by  a  number  of  ganglia;  and  from  the  constant  disposition 
which  it  evinces  in  its  distribution,  to  communicate  and  form  small 
knots  or  ganglia. 

There  are  six  sympathetic  ganglia  in  the  head :  viz.,  the  ganglion 
of  Ribes  ;  the  ciliary  or  lenticular;  the  naso-palatine,  or  Cloquet's; 
the  sphe no-palatine,  or  Meckel's ;  the  submaxillary  ;  and  the  otic,  or 
Arnold's:  three  \\\  \he  neck ;  superior,  middle,  and  inferior:  tivelve 


454 


CRANIAL  GANGLIA. 


in  the  dorsal  region  ;  four  in  the  lumbar  region  ;  and  four  or  five  in 
the  sacral  region. 

Each  ganglion  may  be  considered  as  a  distinct  centre,  giving  off 
branches  in  four  diflerent  directions,  viz.,  superior  or  ascending,  to 
communicate  with  the  ganghon  above ;  inferior  or  descending,  to 
communicate  with  the  ganghon  below;  external,  to  communicate 
with  the  spinal  nerves  ;  and  internal,  to  communicate  with  the  sym- 
pathetic filaments  of  the  opposite  side,  and  to  be  distributed  to  the 
viscera. 

CRANIAL    GANGLIA. 

Ganghon  of  Ribes, 

Ciliary,  or  lenticular  ganglion, 

Naso-palatine,  or  Cloquet's  ganglion, 

Spheno-palatine,  or  Meckel's  ganglion, 

Submaxillary  ganglion, 

Otic,  or  Arnold's  ganglion. 

Fig.  163. 


Fig-.  163.  The  cranial  ganglia  of  the  sympathetic  nerve.  1.  The  ganglion  of  Ribes. 
2.  The  filament  by  which  it  communicates  with  the  carotid  plexus  (3).  4.  The  ciliary 
or  lenticular  ganglion,  giving  off  ciliary  branches  for  the  supply  of  the  globe  of  the 
eye.  5.  Part  of  the  inferior  division  of  the  third  nerve,  receiving  a  short  thick  branch 
from  the  ganglion.  6.  Part  of  the  nasal  nerve,  receiving  a  longer  branch  from  the 
ganglion,  7.  A  slender  filament  sent  directly  backwards  from  the  ganglion  to  the 
sympathetic  branches  in  the  cavernous  sinus,  8.  Piirt  of  the  sixth  nerve  in  the 
cavernous  sinus,  receiving  two  branches  from  the  carotid  plexus.  9.  Meckel's  gan- 
glion (spheno-palatine).  JO.  Its  ascending  branches,  communicating  with  the  superior 
maxillary  nerve.  11.  Its  descending  branches,  tiie  posterior  palatine.  12.  Its  anterior 
branches,  spheno-palatine  or  nasal,  19.  The  naso-palatine  branch,  one  of  the  nasal 
branches,  *  The  swelling  wliicli  Cloquet  imagines  to  be  a  ganglion.  14.  The  pos- 
terior branch  of  the  ganglion,  the  Vidian  nerve.  1.5.  Its  carotid  branch  communicating 
with  tl)c  carotid  plexus.  16.  Its  petrosal  branches,  joining  the  angular  bend  of  the 
facial  norve.  17.  The  fncial  nerve.  18.  The  cliorda  tympani  nerve,  which  descends 
to  join  the  gustatory  nerve.  13.  The  gustatory  nerve.  20.  The  submaxillary  gan- 
glion, receivmg  the  chorda  tympani  nerve  from  tiie  gustatory,  21,  The  superior  cer- 
vical  ganglion  of  the  eyrnpathetic. 


CRAKIAL  GANGLIA.  455 

1.  The  Ganglion"  of  Ribes  is  a  small  ganglion  situated  upon  the 
anterior  communicating  artery,  and  formed  by  the  union  of  the 
sympathetic  filaments,  which  accompany  the  ramifications  of  the 
two  anterior  cerebral  arteries.  These  filaments  are  derived  from 
the  carotid  plexus  at  each  side;  and  through  their  intervention,  the 
ganglion  of  Ribes  is  brought  into  connexion  with  the  carotid 
plexus,  and  with  the  other  ganglia  of  the  sympathetic.  This  gan- 
glion, though  of  very  small  size,  is  interesting,  as  being  the  superior 
point  of  union  between  the  sympathetic  chains  of  opposite  sides  of 
the  body. 

2.  The  Ciliary  Ganglion  {lenticular)  is  a  small  quadrangular  and 
flattened  ganglion  situated  within  the  orbit,  between  the  optic  nerve 
and  the  external  rectus  muscle ;  it  is  in  close  contact  with  the  optic 
nerve,  and  is  surrounded  by  a  quantity  of  fat,  which  renders  its  dis- 
section somewhat  difficult. 

Its  branches  of  distribution  are  the  ciliary,  which  arise  from  its 
anterior  angle  by  two  groups :  the  upper  group,  consisting  of  about 
four  filaments,  and  the  lower,  of  five  or  six.  They  accompany  the 
ciliary  arteries  in  a  waving  course,  and  divide  into  a  number  of 
branches  which  pierce  the  sclerotic  around  the  optic  nerve,  and 
supply  the  tunics  of  the  eyeball.  A  small  filament  is  said,  by 
Tiedemann,  to  accompany  the  arteria  centralis  retinee  into  the  centre 
of  the  globe  of  the  eye. 

Its  branches  of  communication  are  three: — 1.  From  the  posterior 
superior  angle  of  the  nasal  branch  of  the  ophthalmic  nerve.  2.  A 
short  thick  branch  from  the  posterior  inferior  angle  to  the  inferior 
division  of  the  third  nerve.  3.  A  long  filament,  which  passes  back- 
wards to  the  cavernous  sinus,  and  communicates  with  the  carotid 
'plexus. 

3.  The  Naso-palatine  Ganglion  (Cloquet's),  is  a  small  lengthened 
body,  situated  in  the  naso-palatine  canal.  There  is  no  difficulty  in 
finding  it  in  that  situation.  But  it  is  still  a  question  whether  it  be 
actually  a  ganglion.  Arnold  refuses  to  admit  it  in  his  plates  of  the 
cranial  nerves,  and  denies  its  existence  ;  Cruveilhier  agrees  with 
him  in  opinion.  Mr.  Charles  Guthrie,  demonstrator  of  anatomy  in 
the  Charing-Cross  School  of  Medicine,  has  recently  satisfied  himself 
of  its  existence  and  of  its  gansjlionic  nature.* 

\\.s,  branches  of  distribution  are,  two  or  three  small  filaments  to 
the  anterior  part  of  the  palate, — anterior  'palatine  nerves. 

Its  branches  of  communication  are  two  long  delicate  filaments, 
which  ascend  upon  the  septum  narium,  beneath  the  mucous  mem- 
brane, and  pass  across  the  posterior  part  of  the  roof  of  the  nares, 
and  through  the  spleno-palatine  foramina,  to  terminate  in  the  spheno- 
palatine ganglion  at  each  side. 

4.  The  Spheno-palatine  Ganglion  (Meckel's)  the  lai'gest  of  the 
cranial  ganglia  of  the  sympathetic,  is  very  variable  in  its  dimensions. 
It  is  situated  in  the  spheno-maxillary  fossa. 

*  I  have  several  times  dissected  for  this  ganglion,  and  have  as  yet  never  failed  to 
find  it.— G. 


456  SUBMAXILLARY  GANGLION. 

Its  branches  are  divisible  into  four  groups  :  ascending,  descending, 
anterior  or  internal,  and  posterior. 

The  branches  of  distribution  are,  the  internal  or  nasal,  four  or 
five  in  number,  which  enter  the  nose  through  the  spheno-palatine 
foramen,  and  supply  the  mucous  membrane  of  the  nares;  and  the 
descending  or  posterior  palatine  branches,  three  in  number,  M^hich 
pass  downwards  through  the  posterior  palatine  canal,  and  are  dis- 
tributed to  the  mucous  membrane  of  the  nose  and  antrum  maxillare, 
to  the  velum  palati  and  to  the  palate. 

The  branches  of  communication  are  the  ascending,*  two  small 
branches  which  pass  upwards  to  join  the  superior  maxillary  nerve ; 
and  the  posterior  branch  or  Vidian  nerve. 

The  Vidian-f  nerve  passes  directly  backwards  from  the  spheno- 
palatine ganglion,  through  the  pterygoid  or  Vidian  canal,  to  the 
foramen  lacerum  basis  cranii,  where  it  divides  into  two  branches, 
the  carotid  and  pelrosalX  The  carotid  branch  enters  the  carotid 
canal,  and  joins  the  carotid  plexus.  The  petrosal  branch  enters  the 
cranium  through  the  foramen  lacerum  basis  cranii,  and  passes 
backwards  beneath  the  Casserian  ganglion,  and  beneath  the  dura 
mater,  lying  in  a  groove  upon  the  anterior  surface  of  the  petrous 
bone,  to  the  hiatus  Fallopii.  Entering  the  hiatus  Fallopii  it  imme- 
diately joins  the  facial  nerve,  just  as  that  cord  is  making  its  angular 
bend,  previously  to  winding  back  along  the  inner  wall  of  thetympa- 
num.§  The  petrosal  branch  accompanies  the  facial  nerve,  along 
the  aquseductus  Fallopii,  enclosed  in  its  sheath  to  within  a  few  lines 
of  the  stylo-mastoid  foramen.  It  then  quits  the  facial  nerve,  return- 
ing upon  itself  at  an  acute  angle,  and  enters  the  tympanum  near  the 
base  of  the  pyramid.  It  now  takes  the  name  of  chorda  tynipani  3ind 
crosses  the  tympanum  enveloped  in  mucous  membrane,  between  the 
handle  of  the  malleus  and  long  process  of  the  incus  to  the  fissura 
Glaseri ;  passing  through  a  particular  opening  in  this  fissure  it 
descends  upon  the  inner  side  of  the  condyle  of  the  lower  jaw,  and 
internally  to  the  auricular  and  inferior  dental  nerves  to  the  gusta- 
tory nerve,  which  it  joins  at  an  acute  angle.||     Accompanying  the 

*  Arnold  figures,  in  his  beautiful  plates  of  the  cranial  nerves,  two  small  ascending 
filaments  which  enter  the  orbit  and  join  the  optic  nerve. 

+  Guido  Guidi,  latinized  into  Vidus  Vidius,  was  professor  of  anatomy  and  medicine 
in  the  College  of  France  in  1542.  His  work  is  posthumous,  and  was  published  in 
1611. 

t  Or  the  deep  and  superficial  petrous. — G. 

§  Here  two  rival  opinions  clash;  one  set  of  anatomists,  and  with  them  Swan  and 
Arnold,  believe  that  the  petrosal  branch  unites  with  the  substance  of  the  facial  nerve; 
the  two  latter  writers  even  go  so  far  as  to  describe  a  ganglionic  enlargement  upon  the 
facial  nerve  at  this  point,  and  Arnold  would  seem  to  intimate  that  the  nerve  is  actually 
a  branch  of  this  ganglion ;  while  another  set  maintain  that  the  petrosal  branch  merely 
accompanies  the  facinl  nerve,  being  enclosed  in  its  neurilemma.  As  the  question  is 
yet  litigated,  and  as  I  am  prepared  with  no  positive  proof  to  decide  for  either  party,  I 
fihall  at  present  adopt  the  latter  view  as  tlie  more  convenient  for  description,  and  for 
explaining  the  connexions  between  the  different  cranial  ganglia.  The  latter  opinion 
has  for  its  supporters,  Cloquct,  Ribcs,  and  Hirzel. 

II  Here  again,  the  question  effusion  of  nervous  substance,  or  mere  contact,  has  been 
warmly  agitated,  but  with  no  positive  and  unquestionable  results. 


OTIC  GANGLION CAROTID  PLEXUS.  457 

gustatory,  enclosed  in  its  sheath,  to  the  submaxillary  gland,  it  quits 
that  nerve  and  communicates  with  the  submaxillary  gangHon. 

The  petrosal  branch  of  the  Vidian  nerve  receives  a  branch  from 
the  tympanic  nerve  while  in  the  hiatus  Fallopii. 

The  Vidian  nerve  thus  becomes  the  medium  of  communication 
between  the  spheno-palatine  ganglion  and  submaxillary  ganglion ; 
and  between  both  of  these  ganglia  and  the  carotid  plexus ;  and 
through  the  tympanic  nerve  with  the  glosso-pharyngeal  and  pneumo- 
gastric  nerves:  and  if  the  fusion  of  nervous  substance  be  admitted 
between  the  whole  of  these  and  the  facial,  the  auditory,  and  the 
gustatory  nerves. 

5.  The  Submaxillary  Ganglion  is  of  small  size,  but  very  distinct, 
and  is  situated  in  the  submaxillary  gland. 

Its  branches  of  distribution  are  numerous,  and  ramify  upon  the 
ducts  of  the  gland,  and  upon  Wharton's  duct. 

Its  branches  of  communication  are, — 1,  one  or  two  small  branches 
which  join  the  gustatory  nerve ;  and  2,  several  minute  branches 
■which  communicate  with  the  sympathetic  filaments  ramifying  upon 
the  facial  artery.  It  is  associated  with  the  carotid  plexus,  and 
the  other  cranial  ganglia,  by  means  of  the  petrosal  branch  of  the 
Vidian. 

6.  The  Otic  Ganglion  (Arnold's)*  is  a  small  red  body,  resting 
against  the  inner  surface  of  the  inferior  maxillary  nerve,  imme- 
diately below  the  foramen  ovale;  it  is  in  relation  externally  with. 
the  trunk  of  the  inferior  maxillary  nerve,  just  at  the  point  of  union 
of  the  motor  root ;  internally  it  rests  against  the  cartilage  of  the 
Eustachian  tube  and  tensor  palati  muscle ;  and  posteriorly  it  is  in 
contact  with  the  arteria  meningea  magna.  It  is  closely  adherent 
to  the  internal  pterygoid  nerve,  and  appears  like  a  swelling  upon 
that  branch. 

The  branches  of  the  otic  ganglion  are  seven  in  number;  two  of 
distribution,  and  five  of  communication. 

The  branches  of  distribution  are, — 1,  a  small  filament  to  the 
tensor  tympani  muscle;  and,  2,  one  to  the  tensor  palati  muscle. 

The  branches  of  communication  are, — 1,  two  or  three  small 
branches  to  the  motor  root  of  the  inferior  maxillary  nerve ;  2,  two 
branches  to  the  auricular  nerve;  3,  a  filament  to  the  facial  nerve; 
4,  a  long  filament,  the  nervius  petrosus  siiperficialis  ininor,  to  com- 
municate with  the  tympanic  nerve  (Jacobson's)  in  the  tympanum ; 
and,  5,  one  or  two  small  branches  which  join  the  sympathetic  fila- 
ments of  the  arteria  meningea  media  artery. 

Carotid  Plexus. — The  ascending  branch  of  the  superior  cervical 
ganglion  enters  the  carotid  canal  with  the  internal  carotid  artery, 
and  divides  into  two  branches,  which  form  several  loops  of  com- 
munication with  each  other  around  the  artery.  This  constitutes 
the  carotid  plexus.     They  also  form  frequently  a  small  gangliform 

*  Frederick  Arnold,  "  Dissertatio  Inauguralis  de  Parte  Ccphalica  Ncrvi  Sympa- 
thetici."     Heidelberg-,  1826 ;  and  "  Ueber  den  Ohrkrioten,"  1828, 

39 


458  CERVICAL  GANGLIA. 

swelling  upon  the  under  part  of  the  artery,  which  is  called  the 
carotid  ganglion.  The  latter,  however,  is  not  constant;  and,  as  it 
performs  no  special  function,  we  do  not  include  it  amongst  the 
cranial  ganglia  of  the  sympathetic.  The  continuation  of  the  caro- 
tid plexus  onwards  with  the  artery  by  the  side  of  the  sella  turcica, 
is  called  the  cavernous  -jylexus. 

The  carotid  plexus  is  the  centre  of  communication  between  all 
the  cranial  ganglia ;  and  being  derived  from  the  superior  cervical 
ganglion,  between  the  cranial  ganglia  and  those  of  the  trunk,  it  also 
communicates  with  the  greater  part  of  the  cerebral  nerves,  and 
distributes  filaments  with  each  of  the  branches  of  the  internal  caro- 
tid, which  accompany  tho<e  branches  in  all  their  ramifications. 

Thus,  the  GavgUon  of  Ribes  is  formed  by  the  union  of  the  fila- 
ments which  accompany  the  anterior  cerebral  arteries,  and  which 
meet  on  the  anterior  communicating  artery.  The  ciliary  ganglion 
communicates  with  the  plexus  by  means  of  the  long  branch  which 
is  sent  back  to  join  it  in  the  cavernous  sinus.  The  spheno-palatine, 
and  with  it  the  naso-palatine  ganglion,  joins  the  plexus  by  means 
of  the  carotid  branch  of  the  Vidian.  The  submaxillary  ganglion  is 
also  connected  with  it  through  the  Vidian.  And  the  otic  ganglion 
is  brought  in  relation  with  it  by  means  of  the  tympanic  nerve  and 
by  the  Vidian. 

It  communicates  with  the  third  nerve  in  the  cavernous  sinus, 
and  through  the  ciliary  ganglion;  with  the  Casserian  ganglion; 
with  the  ophthalmic  division  of  the  fifth  in  the  cavernous  sinus,  and 
by  means  of  the  ciliary  ganglion;  with  the  superior  maxillary, 
through  the  spheno-palatine  ganglion;  and  with  the  inferior  maxil- 
lary, through  the  chorda  tympani  and  Vidian.  It  sends  two 
branches  directly  to  the  sixth  nerve,  which  unite*  with  it  as  it 
crosses  the  cavernous  sinus;  it  communicates  with  the  facial  and 
auditory  nerves,  through  the  medium  of  the  petrosal  branch  of  the 
Vidian  ;  and  with  the  ginsso-pharyngeal  and  pneumogastric  nerves, 
through  the  nervus  petrnsus  superjicialis  minor,  a  branch  from  the 
Otic  ganglion  to  the  tympanic  nerve. 

CERVICAL    GANGLIA. 

The  Superior  cervical  ganglion  is  long  and  fusiform,  of  a  grayish 
colour,  smooth,  and  of  considerable  thickness,  extending  from 
within  an  inch  of  the  carotid  foramen  in  the  petrous  bone  to  oppo- 
site the  lower  border  of  the  third  cervical  vertebra.  It  is  in  relation 
in  front  with  the  stieath  of  the  internal  carotid  artery  and  internal 
jugular  vein;  and  behind  with  the  rectus  anticus  major  muscle. 

Its  branches,  like  those  of  all  the  sympathetic  ganglia  in  the 
trunk,  are  divisible  into  superior,  inferior,  external,  and  internal; 
to  which  may  added,  as  proper  to  this  ganglion,  anterior. 

*  Panizr.n,  in  his  "  Expcrimcntnl  Roscnrchcs  on  tho  Nerves,"  denies  tliis  communi- 
cation, and  strifes  very  VMyiicly  tlKit  "  ihcy  ;ire  merely  lost  and  entwined  around  it." — 
Edinburgh  Medical  and  Hurgicul  Juurnal,  January,  IbSG. 


CERVICAL  GANGLIA. 


459 


Tig.  164. 


The  superior  is  a  single 
branch  which  ascends  by 
the  side  of  the  internal 
carotid,  and  divides  into 
two  branches ;  one  lying  to 
the  outer  side,  the  oiher  to 
the  inner  side  of  that  vessel. 
The  two  branches  enter  the 
carotid  canal,  and  commu- 
nicate by  means  of  several 
filamenis  sent  from  one  to 
the  other,  to  constitute  the 
carotid  plexus. 

The  inferior  or  descend- 
ing branch,  sometimes  two, 
is  the  cord  of  communica- 
tion with  the  middle  cer- 
vical ganglion. 

The  external  brandies 
are  numerous,  and  may  be 
divided  into  two  sets:  1, 
Those  which  communicate 
with  the  glosso-pharyngeal, 
pueumogastric,  and  hypo- 
glossal nerves ;  and,  2, 
those  which  communicate 
with  the  three  first  cervical 
nerves. 

The  internal  branches 
are  three  in  nunnber:  1. 
Pharyngeal,  to  assist  in 
forming  the  pharyngeal 
plexus;  2.  Laryngeal,  to 
join  the  superior  laryngeal 
nerve  and  its  branches ; 
and,  3.  The  superior  car- 
diac nerve,  or  nervus  super- 
ficialis  cordis. 

The    anterior    branches 


Fig-.  164.  A  view  of  ttie  great  sympatlietic  nerve,  a.  The  cavity  of  the  cranium,  e. 
The  j^lobe  of  the  eye.  c.  I'he  septuin  of  the  nose.  d.  The  incisor  teeth,  e.  TIk;  sub- 
maxillary gfland.  F.  The  larynx,  g.  The  heart,  ii.  The  left  lung-,  i.  The  ca?liac  axis.  j. 
The  ascending  vena  cava.  k.  The  l?idney.  l.  The  crista  of  tlie  ilium,  m.  Tlie  bladder 
N.  The  rectum,  o.  The  pubes.  1.  Plexus  on  the  carotid  artery  in  tlie  carotid  foramen. 
2.  Sixth  nerve,  (motor  externus).  3.  1st  of  the  fifth  or  ophthalmic  nerve.  4.  Branch 
on  the  septum  narium,  connecting  Meckel's  ganglion  with  Cloquct's  in  tlie  incisive 
foramen.  5.  Immediately  above  the  figure  is  the  recurrent  branch  or  Vidian  nerve, 
dividing  into  the  carotid  and  petrosal  tiranches.  6.  Posterior  palatine  branches.  7. 
Lingual  nerve  joined  by  the  chorda  tympani.  8.  The  portio  dura  of  ihe  seventh  pair 
or  facial  nerve.  9.  The  superior  cervical  ganglion.  10.  The  middle  cervicnl  gan- 
glion. 11.  The  inferior  cervical  ganglion.  12.  The  roots  of  the  great  splanchnic  nerve, 
arising  from  the  dorsal  ganglia.  J  3.  The  lesser  splanchnic  nerve.  14.  The  renal 
plexus.  15.  The  solar  plexus.  16.  The  mesenteric  plexus.  17.  The  lumbar  ganglia. 
18.  The  sacral  ganglia.  19.  The  vesical  plexus.  20.  The  rectal  plexus.  21.  The 
lumbar  plexus,  (cerebrospinal.) 


460  CARDIAC  NERVES. 

accompany  the  carotid  artery  with  its  branches,  around  which 
they  form  intricate  plexuses ;  they  are  called,  from  the  softness  of 
their  texture,  nervi  m.oUes. 

The  Middle  cervical  ganglion  (thyroid  ganglion)  is  of  small  size, 
and  sometimes  altogether  wanting.  It  is  situated  opposite  the  fifth 
cervical  vertebra,  and  rests  upon  the  inferior  thyroid  artery.  This 
relation  is  so  constant,  as  to  have  induced  Haller  to  name  it  the 
"  thyroid  ganglion." 

Its  superior  branch,  or  branches,  ascend  to  communicate  with  the 
superior  cervical  ganglion. 

Its  inferior  branches  descend  to  join  the  inferior  cervical  gan- 
glion. 

Its  external  branches  communicate  with  the  third,  fourth,  and 
fifth  cervical  nerves. 

Its  internal  branch  is  the  middle  cardiac  nerve,  nervus  cardiacus 
magnus. 

The  Inferior  cervical  ganglion  (vertebral  ganglion)  is  much 
larger  than  the  preceding,  and  is  constant  in  its  existence.  It  is  of 
a  semilunar  form,  and  is  situated  upon  the  base  of  the  transverse 
process  of  the  seventh  cervical  vertebra,  immediately  behind 
the  vertebral  artery :  hence  its  title  to  the  designation  "  vertebral 
ganglion." 

Its  superior  branches  communicate  with  the  middle  cervical  gan- 
glion. 

The  inferior  branches  pass  some  before  and  some  behind  the  sub- 
clavian artery,  to  join  the  first  thoracic  ganglion. 

The  external  branches  consist  of  two  sets  ;  one  which  communi- 
cates with  the  sixth,  seventh,  and  eighth  cervical  nerves ;  and  one 
which  accompanies  the  vertebral  artery  along  the  vertebral  canal, 
forming  the  vertebral  plexus.  This  plexus  sends  filaments  to  all  the 
branches  given  off  by  the  artery,  and  communicates  in  the  skull 
with  the  filaments  of  the  carotid  plexus  accompanying  the  branches 
of  the  internal  carotid  artery. 

The  internal  branch  is  the  inferior  cardiac  nerve,  nervus  cardi- 
acus minor. 

Cardiac  Nerves.* — The  superior  cardiac  nerve  {nervus  super- 
ficialis  cordis)  arises  from  the  lower  part  of  the  superior  cervical 
ganglion  ;  it  then  descends  the  neck  behind  the  common  carotid 
artery,  and,  parallel  with  the  trachea,  crosses  the  inferior  thyroid 
artery,  and  accompanying  the  recurrent  laryngeal  nerve  for  a  short 
distance,  passes  behind  the  arteria  innominata*to  the  concavity  of 
the  arch  of  the  aorta,  where  it  joins  the  cardiac  ganglion. 

In  its  course  it  receives  branches  from  the  pneumogastric  nerve, 
and  sends  filaments  to  the  thyroid  gland  and  trachea. 

The  Middle  cardiac  nerve  [nervus  cardiacus  magnus)  proceeds 
from  the  middle  cervical  ganglion,  or,  in  its  absence,  from  the  cord 

*  There  is  no  constancy  with  regard  to  the  origin  and  course  of  these  nerves;  there- 
fore the  student  must  not  be  disappointed  in  finding  the  description  in  discord  with  his 
dissection. 


CARDIAC  GANGLION THORACIC  GANGLIA.  461 

of  communication  between  the  superior  and  inferior.  It  is  the 
largest  of  the  three  nerves,  and  lies  nearly  parallel  with  the  recur- 
rent laryngeal.  At  the  root  of  the  neck  it  divides  into  several 
branches,  which  pass  some  before  and  some  behind  the  subclavian 
artery;  it  communicates  with  the  superior  and  inferior  cardiac, 
and  with  the  pneumogastric  and  recurrent  nerves,  and  descends  to 
the  bifurcation  of  the  trachea,  to  the  great  cardiac  'plexus. 

The  Inferior  cardiac  nerve  {nervus  cardiacus  minor)  arises  from 
the  inferior  cervical  ganglion,  communicates  freely  with  the  recur- 
rent laryngeal  and  middle  cardiac  nerves,  and  descends  to  the  front 
of  the  bifurcation  of  the  trachea,  to  join  the  great  cardiac  plexus. 

The  Cardiac  ganglion  is  a  ganglionic  enlargement  of  variable 
size,  situated  beneath  the  arch  of  the  aorta,  to  the  right  side  of  the 
ligament  of  the  ductus  arteriosus.  It  receives  the  superior  cardiac 
nerves  of  opposite  sides  of  the  neck,  and  a  branch  from  the  pneu- 
mogastric nerve,  and  gives  off  numerous  branches  to  the  cardiac 
plexuses. 

The  Great  cardiac  plexus  is  situated  upon  the  bifurcation  of  the 
trachea,  above  the  right  pulmonary  artery,  and  behind  the  arch  of 
the  aorta.  It  is  formed  by  the  convergence  of  the  middle  and 
inferior  cardiac  nerves,  and  by  branches  from  the  pneumogastric 
nerve. 

The  Anterior  cardiac  plexus  is  situated  in  front  of  the  ascending 
aorta,  near  to  its  origin.  It  is  formed  by  the  communications  of 
filaments  that  proceed  from  three  different  sources.  1st,  from  the 
superior  cardiac  nerves,  crossing  the  arch  of  the  aorta;  2dly,  from 
the  cardiac  ganglion  beneath  the  arch;  and  3dly,  from  the  great 
cardiac  plexus, — passing  between  the  ascending  aorta  and  the 
right  auricle.  The  anterior  cardiac  plexus  supplies  the  anterior 
aspect  of  the  heart,  distributing  numerous  filaments  with  the  left 
coronary  artery,  which  form  the  anterior  coronary  plexus. 

The  Posterior  cardiac  plexus  is  formed  by  numerous  branches 
from  the  great  cardiac  plexus,  and  is  situated  upon  the  posterior 
part  of  the  ascending  aorta,  near  to  its  origin.  It  divides  into  two 
sets  of  branches:  one  set  accompanying  the  right  coronary  artery 
in  the  auriculo-ventricular  sulcus  ;  the  other  set  joining  the  artery 
on  the  posterior  aspect  of  the  heart.  They  both  together  constitute 
the  posterior  coronary  plexus. 

The  great  cardiac  plexus  likewise  gives  branches  to  the  ricueals 
of  the  heart,  and  others,  to  assist  in  forming  the  anterior  and  poste- 
rior pulmonary  plexuses. 

THORACIC     GANGLIA. 

The  Thoracic  ganglia  are  twelve  in  number  on  each  side.  They 
are  flattened  and  triangular,  or  irregular  in  form,  and  present  the 
peculiar  gray  colour  and  pearly  lustre  of  the  other  s^'mpathetic 
ganglia;  they  rest  upon  the  heads  of  the  ribs,  and  are  covered  in 
by  the  pleura  costalis.  The  two  first  and  the  last  ganglia  are 
usually  the  largest. 

39* 


462  SEMILUNAR  GANGLION SOLAR  PLEXUS. 

Their  branches  are  superior,  inferior,  external  and  internal. 

The  superior  and  inferior  are  prolongations  of  the  substance  of 
the  ganglia  rather  than  branches;  the  former  to  communicate  with 
the  ganglion  above,  the  latter  with  that  below. 

The  external  branches,  two  or  three  in  number,  communicate  with 
each  of  the  spinal  nerves. 

The  internal  branches  of  the  five  upper  ganglia  are  aortic,  and 
follow  the  course  of  the  intercostal  arteries  to  that  trunk :  the 
branches  of  the  lower  ganglia  unite  to  form  the  two  splanchnic 
nerves. 

The  Great  splanchnic  nerve  arises  from  the  sixth  dorsal  ganglion, 
and  receives  branches  from  the  seventh,  eighth,  ninth  and  tenth, 
which  increase  it  to  a  nerve  of  considerable  size.  It  descends  in 
front  of  the  vertebral  column,  within  the  posterior  mediastinum, 
pierces  the  diaphragm  immediately  to  the  outer  side  of  each  crus, 
and  terniinates  in  the  semilunar  ganglion. 

The  Lesser  splanchnic  nerve  (renal)  is  formed  by  filaments  from 
the  tenth,  eleventh,  and  sometimes  from  the  twelfth  dorsal  ganglion. 
It  pierces  the  diaphragm,  and  descends  to  join  the  renal  plexus. 

The  Semilunar  ganglion  is  a  large,  irregular,  gangliform  body, 
pierced  by  numerous  openings,  and  appearing  like  the  aggregation 
of  a  number  of  smaller  ganglia,  having  spaces  between  them.  It  is 
situated  by  the  side  of  the  cceliac  axis,  and  communicates  with  the 
ganglion  of  the  opposite  side,  both  above  and  below  that  trunk,  so 
as  to  form  a  gangliform  circle,  from  which  branches  pass  off  in  all 
directions,  like  rays  from  a  centre.  Hence  the  entire  circle  has 
been  named  the  solar  plexus. 

The  Solar  plexus  receives  the  great  splanchnic  nerves;  part  of 
the  lesser  splanchnic  nerves;  the  termination  of  the  right  pneumo- 
gastric  nerve;  some  branches  from  the  right  phrenic  nerve;  and 
sometimes  one  or  two  filaments  from  the  left.  It  gives  off  nume- 
rous filaments,  which  accompany,  under  the  name  of  plexuses,  all 
the  brnnches  given  off  by  the  abdominal  aorta.  Thus,  we  have 
derived  from  the  solar  plexus  the — 

Phrenic  plexuses, 
Gastric  plexus, 
Hepatic  plexus, 
Splenic  plexus, 
Supra-renal  plexuses, 
Rennl  plexuses, 
Superior  mesenteric  plexus, 
Spermatic  plexuses, 
Inferior  mesenteric  plexus. 

The  Renal  plexus  is  formed  chiefly  by  the  lesser  splanchnic  nerve, 
but  receives  many  filaments  from  the  solar  plexus. 

The  Spermatic  plexus  is  formed  principally  by  the  renal  plexus. 

The  Inferior  mesenteric  plexus  receives  filaments  from  the  aortic 
plexus. 


LUMBAR  AND  SACRAL  GANGLIA.  463 


LUMBAR     GANGLIA. 


The  Lumbar  gavglia  are  four  in  number  on  each  side,  of  the 
peculiar  pearly  gray  colour,  fusiform,  and  situated  upon  the  anterior 
part  of  the  bodies  of  the  lumbar  vertebrae. 

The  superior  and  inferior  branches  of  the  lumbar  ganglia  are 
branches  of  communication  with  the  ganglion  above  and  below,  as 
in  the  dorsal  region. 

The  external  branches,  two  or  three  in  number,  communicate 
with  the  lumbar  nerves. 

The  internal  branches  consist  of  two  sets  ;  of  which  the  upper 
pass  inwards  in  front  of  the  abdominal  aorta,  and  form  around  that 
trunk  a  plexiform  interlacement,  which  constitutes  the  aortic  -plexus; 
the  lower  branches  cross  the  common  iliac  arteries,  and  unite  over 
the  promontory  of  the  sacrum,  to  form  the  hypogastric  plexus. 

The  Aortic  plexus  is  formed  by  branches  from  the  lumbar  ganglia, 
and  receives  filaments  from  the  solar  and  superior  mesenteric 
plexuses.  It  sends  filaments  to  the  inferior  mesenteric  plexus,  and 
terminates  in  the  hypogastric  plexus. 

The  Hypogastric  plexus  is  formed  by  the  termination  of  the  aortic 
plexus,  and  by  the  union  of  branches  from  the  lower  lumbar  gan- 
glia. It  is  situated  over  the  promontory  of  the  sacrum,  between  the 
two  common  iliac  arteries,  and  bifurcates  inferiorly  into  two  lateral 
portions,  which  communicate  with  branches  from  the  fourth  and 
filth  sacral  nerves.  It  distributes  branches  to  all  the  viscera  of  the 
pelvis,  and  to  the  branches  of  the  internal  iliac  artery. 

SACRAL    GANGLIA. 

The  Sacral  ganglia  are  four  or  five  in  number  on  each  side.  They 
are  situated  upon  the  sacrum,  close  to  the  anterior  sacral  foramina, 
and  resemble  the  lumbar  ganglia  in  form  and  mode  of  connexion, 
although  they  are  much  smaller  in  size. 

The  superior  and  inferior  branches  communicate  with  the  gan- 
glia above  and  below. 

The  external  branches  communicate  with  the  sacral  and  coccy- 
geal nerves. 

The  internal  branches  communicate  very  freely  with  the  lateral 
divisions  of  the  hypogastric  plexus,  and  are  distributed  to  the  pelvic 
viscera.  The  last  sacral  ganglia  of  the  opposite  sides  give  off 
branches  which  join  a  small  ganglion,  situated  on  the  first  bone  of 
the  coccyx,  called  the  ganglion  impar  or  azygos.  This  ganglion 
resembles  in  its  position  and  function  the  ganglion  of  Ribes,  serving 
to  connect  the  inferior  extremity  of  the  sympathetic  system,  as  does 
the  former  ganglion  its  upper  extremity.  It  gives  qff  a  few  small 
branches  to  the  coccyx  and  rectum. 


CHAPTER  IX. 


ORGANS    OF    SENSE. 


The  organs  of  sense,  the  instruments  by  which  the  animal  frame 
is  brought  into  relation  with  surrounding  nature,  are  five  in  number. 
Four  of  these  organs  are  situated  within  the  head,  viz.  the  apparatus 
of  smell,  sight,  hearing,  and  taste,  and  the  remaininig  organ,  of 
touch,  is  resident  in  the  skin,  and  is  distributed  over  the  entire  sur- 
face of  the  body. 


THE    NOSE    AND    NASAL    FOSS^. 


The  organ  of  smell  consists  essentially  of  two  parts :  one  exter- 
nal, tke  nose;  the  other  internal,  the  nasal fossce. 

The  nose  is  the  triangular  pyramid  projecting  from  the  centre  of 
the  face,  immediately  above  the  upper  lip.  Superiorly,  it  is  con- 
nected with  the  forehead,  by  means  of  a  narrow  bridge;  inferiorly, 
it  presents  two  openings,  the  nostrils,  which  overhang  the  mouth, 
and  are  so  constructed  that  the  odour  of  all  substances  must  be  re- 
ceived by  the  nose  before  they  can  be  introduced  within  the  lips. 
The  septum  between  the  openings  of  the  nostrils  is  called  the  columna. 
Their  entrance  is  guarded  by  a  number  of  stiff  hairs  (vibrissce), 
which  project  across  the  openings,  and  act  as  a  filter  in  preventing 
the  introduction  of  foreign  substances,  such  as  dust  or  insects,  with 
the  current  of  air  intended  for  respiration. 

The  anatomical  elements  of  which  the  nose  is  composed  are, — 1. 
Integument.  2.  Muscles.  3.  Bones.  4.  Fibro-cartilages.  5.  Mu- 
cous membrane.     6.  Vessels  and  nerves. 

1.  The  Integument  forming  the  tip  (lohulus)  and  wings  (o/ce)  of 
the  nose  is  extremely  thick  and  dense,  so  as  to  be  with  difficulty 
.separated  from  the  fibro-cartilage.  It  is  furnished  with  a  number 
of  sebaceous  follicles,  which  by  their  oily  secretion,  protect  the  ex- 
tremity of  the  nose  in  excessive  alternations  of  temperature.  The 
sebaceous  matter  of  these  follicles,  becomes  of  a  dark  colour  upon 
the  surface,  from  the  attraction  of  the  carbonaceous  matter  floating 
in  the  atmosphere:  hence  the  spotted  appearance  which  the  tip  of 
the  nose  presents  in  large  cities.  When  the  integument  is  firmly 
compressed,  the  inspissated  sebaceous  secretion  is  squeezed  out 
from  the  follicles,  and  taking  the  cylindrical  form  of  their  excretory 
ducts,  has  the  appearance  of  small  white  maggots  with  black  heads. 


CARTILAGES  OF  THE  NOSE. 


465 


riff.  165. 


2.  The  Muscles  are  brought  into  view  by  reflecting  the  integu- 
ment: they  arc  the  pyramidalis  nasi,  compressor  nasi,  levator  labii 
superioris  alteque  nasi,  and  depressor  labii  superioris  alaeque  nasi. 
They  have  been  already  described  with  the  nnuscles  of  the  face. 

3.  The  Bones  of  the  nose  are  the  nasal,  and  nasal  processes  of 
the  superior  nnaxillary. 

4.  The  Fihro-carlilages  give  form  and  stability  to  the  outw^ork  of 
the  nose,  providing  at  the  same  time,  by  their  elasticity,  against  in- 
juries.    They  are  five  in  number,  the 

Fibro-cartilage  of  the  septum, 
Two  lateral  fibro-cartilages, 
Two  alar  fibro-cartilages. 

The  FibTo- cartilage  of  the  septum,  somewhat  triangular  in  form, 
divides  the  nose  into  its  two  nostrils.  It  is  connected  above  with 
the  nasal  bones  and  lateral  fibro-cartilages;  behind,  with  the  eth- 
moidal septum  and  vomer ;  and  below,  with  the  palate  processes  of 
the  superior  maxillary  bones.  The  alar  fibro-cartilages  and  columna 
move  freely  upon  the  fibro-cartilage  of  the  septum,  being  but  loosely 
connected  with  it  by  perichondrium. 

The  Lateral  fibro-cartilages  are  also  trian- 
gular :  they  are  connected,  in  front,  with  the 
fibro-cartilage  of  the  septum;  above  with  the 
nasal  bones ;  behind  with  the  nasal  processes 
of  the  superior  maxillary  bones ;  and  beloio 
with  the  alar  fibro-cartilages. 

Alar  fibro-cartilages. — Each  of  these  carti- 
lages is  curved  in  such  a  manner  as  to  corre- 
spond with  the  opening  of  the  nostril,  to  which 
it  forms  a  kind  of  rim.  The  inner  portion  is 
loosely  connected  with  the  same  part  of  the 
opposite  cartilage,  so  as  to  form  the  columna. 
It  is  expanded  and  thickened  at  the  point  of  the 
nose  to  constitute  the  lobe;  and  upon  the  side 
forms  a  curve  corresponding  with  the  form  of 
the  ala.  This  curve  is  prolonged  downwards 
and  forwards  in  the  direction  of  the  posterior 
border  of  the  ala  by  three  or  four  small  fibro- 
cartilaginous plates,  which  are  appendages  to  the  alar  fibro-carti- 
lage. 

The  whole  of  these  fibro-cartilages  are  connected  with  each 
other,  and  to  the  bones,  by  perichondrium,  which,  from  its  mem- 
branous structure,  permits  of  the  freedom  of  motion  existing  be- 
tween them. 

5.  The  Mucoiis  membrane,  lining;  the  interior  of  the  nose,  is  con- 


Fi^.  165.  The  fibro-cartilages  of  the  nose.  1.  The  nasal  bones.  2.  The  fibro-carti- 
lage of  the  septum.  3  The  lateral  fibro-cartilages.  4.  The  alar  fibro-cartilages.  5. 
The  central  portions  of  the  alar  fibro-cartilages  which  constitute  the  columna.  6.  The 
appendi.t  of  the  alar  fibro-cartilage.     7.  The  nostrils. 


466  NASAL  FOSS^. 

* 

tinuous  with  the  skin  externally,  and  with  the  pituitary  membrane 
of  the  nasal  fossffi  within.  Around  the  entrance  of  the  nostrils  it  is 
provided  with  numerous  vihrisscR. 

6.  Vessels  and  A^'erves. — The  Arteries  of  the  nose  are  the  lateralis 
nasi  from  the  facial,  and  the  nasalis  septi  from  the  superior  coro- 
nary. 

Its  JVerves  are  the  facial,  infra-orbital,  and  nasal  branch  of  the 
ophthalmic. 

NASAL    FOSSiE. 

To  obtain  a  good  view  of  the  nasal  fossce,  the  face  must  be  di- 
vided through  the  nose  by  a  vertical  incision,  a  little  to  one  side  of 
the  middle  line. 

The  Nasal  fosscB  are  two  irregular,  compressed  cavities,  extend- 
ing backwards  from  the  nose  to  the  pharynx.  They  are  bounded 
superiorly  by  the  sphenoid  and  ethmoid  bones.  Inferiorhj  by  the 
hard  palate;  and  in  the  middle  line  they  are  separated  from  each 
other  by  a  bony  and  fibro-cartilaginous  septum.  A  plan  of  the 
boundaries  of  the  nasal  fossae  will  be  found  at  page  68. 

Upon  the  outer  wall  of  each  fossa,  in  the  dried  skull,  are  three 
projecting  processes,  termed  spongy  bones.  The  tu'o  superior  be- 
long to  the  ethmoid,  the  inferior  is  a  separate  bone.  In  the  fresh 
fossoe  these  are  covered  with  mucous  membrane,  and  serve  to  in- 
crease its  surface  by  their  projection  and  by  their  convoluted  form. 
The  space  intervening  between  the  superior  and  middle  spongy 
bones  is  the  superior  meatus;  the  space  between  the  middle  and  in- 
ferior bones  is  the  middle  meatus ;  and  that  between  the  inferior 
and  the  floor  of  the  fossa  is  the  inferior  meatus. 

These  meatuses  are  passages  which  extend  from  before  back- 
wards, and  it  is  in  rushing  through  and  amongst  these  that  the  at- 
mosphere deposits  its  odorant  particles  upon  the  mucous  membrane. 
There  are  several  openings  into  the  nasal  fossae :  thus,  in  the  supe- 
rior meatus  are  the  openings  of  the  sphenoidal  and  posterior  ethmoi- 
dal cells,  in  the  middle  the  anterior  ethmoidal  cells,  the  frontal 
sinuses,  and  the  antrum  maxillare;  and,  in  the  inferior  meatus,  the 
termination  of  the  nasal  duct.  In  the  dried  bone  there  arc  two  addi- 
tional openings,  the  spheno-palatine  and  the  anterior  palatine  fora- 
men; the  former  being  situated  in  the  superior,  and  the  latter  in 
the  inferior  meatus. 

The  Mucous  membrane  of  the  nasal  fossoe  is  called  pituitary,  or 
Schneiderian.*  The  former  name  being  derived  from  its  secretion, 
the  latter  from  Schneider,  who  was  the  first  to  show  that  the  secre- 
tion of  the  nose  proceeded  from  the  mucous  membrane,  and  not 
from  the  brain,  as  was  formerly  imagined.  It  is  continuous  with 
the  general  gastro-pulmonary  mucous  membrane,  and  may  be  traced 
through  the  openings  in  the  meatuses,  into  the  sphenoidal  and  eth- 

*  Conrad  Victor  Schneider,  Professor  of  Medicine  at  Wittenberg.  His  work,  enti- 
tled De  Calarrhis,  &,c.,  was  published  in  IGOl, 


THE  EYE SCLEROTIC  COAT.  467 

moidal  cells;  into  the  antrum  maxillare;  through  the  nasal  duct  to 
the  surface  of  the  eye,  where  it  is  continuous  with  the  conjunctiva  ; 
along  the  Eustachian  tubes  into  the  tynnpanum  and  mastoid  cells, 
to  which  it  forms  the  lining  membrane;  and  through  the  poslerior 
nares  into  the  pharynx  and  mouth,  and  thence  through  the  lungs 
and  alimentary  canal. 

The  surface  of  this  membrane  is  furnished  with  a  columnar  epi- 
thelium supporting  innumerable  vibratile  ciha. 

Vessels  and  JVeroes. — The  Arteries  of  the  nasal  fossae  are  the  an- 
terior and  posterior  ethmoidal,  from  the  ophthalmic  artery;  and 
spheno-palatine  and  pterygo-palaline  from  the  internal  maxillary. 

The  JVerves  are,  the  olfactory,  the  spheno-palatine  branches  from 
Meckel's  ganglion,  and  the  nasal  branch  of  the  ophthalmic.  The 
ultimate  filaments  of  the  olfactory  nerve  terminate  in  minute  pa- 
pillsB. 

THE    EYE,    WITH   ITS   APPENDAGES. 

The  form  of  the  eyeball  is  that  of  a  sphere,  of  about  one  inch  in 
diameter,  having  the  segment  of  a  smaller  sphere  ingrafted  upon  its 
anterior  surface,  which  increases  its  antero-posterior  diameter. 
The  axes  of  the  two  eyeballs  are  parallel  with  each  other,  but  do 
not  correspond  with  the  axes  of  the  orbits,  which  are  directed  out- 
wards. The  optic  nerves  follow  the  direction  of  the  orbits,  and 
therefore  enter  the  eyeballs  to  their  nasal  side. 

The  Globe  of  the  Eye  is  composed  of  tunics  and  of  refracting 
media  called  humours.     The  tunics  are  three  in  number,  the 

1.  Sclerotic  and  Cornea, 

2.  Choroid,  Iris,  and  Ciliary  processes, 

3.  Retina  and  Zonula  ciliaris. 

The  humours  are  also  three — 

Aqueous, 
Ci7stalline  (lens), 
Vitreous. 

1.  The  Sclerotic  and  Cornea  form  the  external  tunic  of  the  eye- 
ball, and  give  to  it  its  peculiar  form.  Four  fifths  of  the  globe  are 
invested  by  the  sclerotic,  the  remaining  fifth  by  the  cornea. 

The  Sclerotic  (cr'xX-ii^o^,  hard)  is  a  dense  fibrous  membrane,  thicker 
behind  than  in  front.  It  is  continuous,  posteriorly,  with  the  sheath 
of  the  optic  nerve,  which  is  derived  from  the  dura  mater,  and  it  is 
pierced  by  that  nerve  as  well  as  by  the  ciliary  nerves  and  arteries. 
Anteriorly  it  presents  a  bevelled  edge  which  receives  the  cornea  in 
the  same  way  that  a  watch-glass  is  received  by  the  groove  in  its 
case.  Its  anterior  surface  is  covered  by  a  thin  tendinous  layer,  the 
tunica  alhyginea,  derived  from  the  expansion  of  the  tendons  of  the 
four  recti  muscles.  By  its  posterior  surface  it  gives  attachment  to 
the  two  oblique  muscles.     The  tunica  albuginea  is  covered,  for  a 


468 


CRYSTALLINE  AND  VITREOUS  HUMOUR. 


part  of  its  extent,  by  the  mucous  membrane  of  the  front  of  the  eye, 
the  conjunctiva  ;  and,  by  reason  of  the  brilliancy  of  its  whiteness, 
gives  occasion  to  the  common  expression,  "  the  white  of  the  eye." 
At  the  entrance  of  the  optic  nerve  the  sclerotic  forms  a  thin 
cribriform  lamella  {lamina  cribrosa),  which  is  pierced  by  a  number 
of  minute  openings  for  the  passage  of  the  nervous  filaments.  One 
of  these  openings,  larger  than  the  rest,  and  situated  in  the  centre  of 
the  lamella,  is  the  poi'us  opticus,  through  which  the  arteria  centralis 
retinae  enters  the  eye. 

Fig.  166. 


The  Cornea  (corneus,  horny)  is  the  transparent  projecting  layer 
that  forms  the  anterior  fifth  of  the  globe  of  the  eye.  In  its  form  it 
is  circular,  concavo-convex,  and  resembles  a  watch-glass.  It  is 
received  by  its  edge,  which  is  sharp  and  thin,  withm  the  bevelled 
border  of  the  sclerotic,  to  which  it  is  very  firmly  attached,  and  it  is 
somewhat  thicker  than  the  anterior  portion  of  that  tunic.  When 
examined  from  the  exterior,  its  vertical  diameter  is  seen  to  be  about 
one-sixteenth  shorter  than  the  transverse,  in  consequence  of  the 
overlapping  above  and  below,  of  the  margin  of  the  sclerotica ;  on 
the  interior,  however,  its  outline  is  perfectly  circular. 

The  cornea  is  composed  of  four  layers,  1,  of  the  conjunctiva ;  2, 
of  the  cornea  proper,  which  consists  of  several  thin  lamellae  con- 
Fig-.  166.  A  longitudinal  section  of  the  globe  of  tlie  eye.  1.  The  sclerotic,  thicker 
behind  than  in  Iront.  2.  The  cornea,  received  within  the  anterior  margin  of  the  scle- 
rotic,  and  connected  with  it  by  means  of  a  bevelled  edge.  '3.  Tlie  choroid,  connected 
anteriorly  with  (4)  the  ciliary  ligament,  and  (5)  the  ciliary  processes.  6.  The  iris. 
7.  'I'he  pupil.  8.  The  third  layer  of  the  eye,  the  retina,  terminating  anteriorly  by  an 
abrupt  border  at  the  commencement  of  the  ciliary  processes.  9.  The  canal  of  Petit, 
which  encircles  the  lens  (12);  the  thin  layer  in  front  of  this  canal  is  tiic  zonula  ciliaris, 
a  prolongation  of  tiic  vascular  layer  of  the  retina  to  the  lens.  10.  The  anterior  cham- 
ber of  the  eye  containing  the  aqueous  huiriour ;  the  lining  mombriine  by  which  the 
humour  is  secreted  is  represented  in  the  diagram.  11.  The  posterior  chamber,  12. 
The  lens,  more  convex  behind  than  before,  and  enclosed  in  its  proper  capsule.  13. 
The  vitreous  humoiir  enclosed  in  the  hyaloid  membrane,  and  in  cells  formed  in  its 
interior  by  that  membrane.  14.  A  tubular  sheath  of  the  hyaloid  membrane,  which 
Bcrves  for  the  passage  of  the  artery  of  the  capsule  of  the  lens,  15.  'I'hc  neurilemma 
of  the  optic  nerve.     16.  The  arteria  centralis  retina;,  embedded  in  its  centre. 


STRUCTURE  OF  THE  CORNEA.  469 

nected  together  by  an  extremely  fine  cellular  tissue;  3,  of  the  cornea 
elastica,  a  "  fine,  elastic,  and  exquisitely  transparent  membrane, 
exactly  applied  to  the  inner  surface  of  the  cornea  proper;"  and  4, 
of  the  lining  membrane  of  the  anterior  chamber  of  the  eyeball.  The 
cornea  elastica  is  remarkable  for  its  perfect  transparency,  even 
when  submitted  for  many  days  to  the  action  of  water  or  alcohol; 
while  the  cornea  proper  is  rendered  perfectly  opaque  by  the  same 
immersion.  To  expose  this  membrane.  Dr.  Jacob  suggests  that  the 
eye  should  be  placed  in  water  for  six  or  eight  days,  and  then  that 
all  the  opaque  cornea  should  be  removed  layer  after  layer.  Another 
character  of  the  cornea  elastica  is  its  great  elasticity,  which  causes 
it  to  roll  up  when  divided  or  torn,  in  the  same  manner  with  the  cap- 
sule of  the  lens.  The  use  of  this  layer,  according  to  Dr.  Jacob,  is 
to  "  preserve  the  requisite  permanent  correct  curvature  of  the 
flaccid  cornea  proper." 

The  opacity  of  the  cornea,  produced  by  pressure  on  the  globe, 
results  from  the  infiltration  of  fluid  into  the  cellular  tissue  connect- 
ing its  layers.  This  appearance  cannot  be  produced  in  a  sound 
living  eye. 

Dissection. — The  sclerotic  and  cornea  are  now  to  be  dissected 
away  from  the  second  tunic ;  this,  with  care,  may  be  easily  per- 
formed, the  only  connexions  subsisting  between  them  being  at  the 
circumference  of  the  iris,  the  entrance  of  the  optic  nerve,  and  the 
perforation  of  the  ciliary  nerves  and  arteries.  Pinch  up  a  fold  of 
the  sclerotic  near  its  anterior  circumference,  and  make  a  small 
opening  into  it,  then  raise  the  edge  of  the  tunic,  and  with  a  pair  of 
fine  scissors,  having  a  probe  point,  divide  the  entire  circumference 
of  the  sclerotic,  and  cut  it  away  bit  by  bit.  Then  separate  it  from 
its  attachment  around  the  circumference  of  the  iris  by  a  gentle 
pressure  with  the  edge  of  the  knife.  The  dissection  of  the  eye 
must  be  conducted  under  water. 

.  In  the  course  of  this  dissection  the  ciliary  nerves  and  long  ciliary 
arteries  will  be  seen  passing  forwards  between  the  sclerotic  and 
choroid,  to  be  distributed  to  the  iris. 

2.  Second  tunic. — The  second  tunic  of  the  eyeball  is  formed  by 
the  choroid,  ciliary  ligament  and  iris,  the  ciliary  processes  being  an 
appendage  developed  from  its  inner  surface. 

The  choroid/'^  is  a  vascular  membrane  of  a  rich  chocolate-brown 
colour  upon  its  external  surface,  and  of  a  deep  black  colour  within. 
It  is  connected  with  the  sclerotic,  externally,  by  an  extremely  fine 
cellular  tissue,  and  by  the  passage  of  nerves  and  vessels.  Internally 

*  The  V!  or  A  choroid  has  been  very  much  abused  in  anatomieal  languag'e ;  it  was 
originally  applied  to  the  membrane  of  the  fetus  called  chorion  from  the  Greek  word 
Xop'ov,  domicilium,  that  membrane  being,  as  it  were,  the  abode  or  receptacle  of  the 
foetus.  Xoptov  comes  from  j^aipsio,  to  take  or  receive.  Now  it  so  happens  that  the  cho- 
rion in  the  ovum  is  a  vascular  membrane  of  a  peculiar  structure.  Hence  tlie  term 
choroid,  ^(^o^icv  nSo;,  like  the  chorion,  has  been  used  indiscriminately  to  signifj'^  vas- 
cular  structures,  as  in  the  choroid  membrane  of  the  eye,  the  choroid  plexus,  &.c.  and 
we  find  Cruveilhicr  in  his  admirable  work  on  Anatomy,  vol.  iii.  p.  463,  saying  in  a 
note,  "  Choroide  est  synonyme  de  vasculeuse." 

40 


470  CILIARY  LIGAMENT IRIS. 


I 


it  is  in  simple  contact  with  the  third  tunic  of  the  eye,  the  retina. 
It  is  pierced  posteriorly  for  the  passage  of  the  optic  nerve,  and  is 
connected  anteriorly  with  the  iris,  ciliary  processes,  and  with  the 
line  of  junction  of  the  cornea  and  sclerotic,  by  a  dense  white  struc- 
ture, the  ciliary  ligament,  which  surrounds  the  circumference  of  the 
iris  like  a  ring. 

The  choroid  membrane  is  composed  of  three  layers: — 1.  An 
external  or  venous,  which  consists  principally  of  veins  arranged  in 
a  peculiar  manner:  hence  they  have  been  named  ven<x.  vorticosce. 
The  marking  upon  the  surface  of  the  membrane  produced  by  these 
veins,  resembles  so  many  centres,  to  which  a  number  of  curved 
lines  converge.  It  is  this  layer  which  is  connected  with  the  ciliary 
ligament.  2.  The  middle  or  arterial  layer  {tunica  Ruyschiana)*  is 
formed  principally  by  the  ramifications  of  minute  arteries,  and 
secretes  upon  its  surface  the  pigmentum  nigrum.  It  is  reflected 
inwards  at  its  junction  with  the  ciliary  ligament,  so  as  to  form  the 
ciliary  processes.  3.  The  internal  layer  is  a  delicate  membrane 
{membrana  pigmenti)  which  presents  a  beautiful  appearance  beneath 
the  microscope;  it  is  composed  of  several  laminae  of  nucleated 
hexagonal  cells,  which  contain  the  granules  of  pigmentum  nigrum, 
and  are  arranged  so  as  to  resemble  a  tesselated  pavement. 

In  animals  the  pigmentum  nigrum,  upon  the  posterior  wall  of  the 
eyeball,  is  replaced  by  a  layer  of  considerable  extent,  and  of  metallic 
brilliancy,  called  the  tapetum. 

The  ciliary  ligament,  or  circle,  is  the  bond  of  union  between  the 
external  and  middle  tunics  of  the  eye,  and  serves  to  connect  the 
cornea  and  sclerotic  at  their  line  of  junction  with  the  iris  and 
external  layer  of  the  choroid.  It  is  also  the  point  to  which  the 
ciliary  nerves  and  vessels  proceed  previously  to  their  distribution, 
and  it  receives  the  anterior  ciliary  arteries  through  the  anterior 
marsrin  of  the  sclerotic.  A  minute  vascular  canal  is  situated  within 
the  ciliary  ligament,  called  the  ciliary  canal,  or  the  canal  of  Fon- 
tana,-)-  from  its  discoverer. 

The  Iris  (iris,  a  rainbow)  is  so  named  from  its  variety  of  colour 
in  different  individuals:  it  forms  a  septum  between  the  anterior  and 
posterior  chambers  of  the  eye,  and  is  pierced  somewhat  to  the  nasal 
side  of  its  centre  by  a  circular  opening,  which  is  called  the  pupil. 
By  its  periphery  it  is  connected  with  the  ciliary  ligament,  and  by 
its  inner  circumference  forms  the  margin  of  the  pupil:  its  anterior 
surface  looks  towards  the  cornea,  and  the  posterior  towards  the 
ciliary  processes  and  lens. 

It  is  composed  of  two  layers,  an  anterior  or  muscular,  consisting 
oi  radiating  fibres  which  converge  from  the  circumference  towards 

*  Rijysch  was  born  at  tho  Hajjuc  in  1638,  and  was  appointed  professor  of  Anatomy 
at  Amsterdam  in  1G(J.'3.  His  whole  life  was  employed  in  making  injected  prepara- 
tions, for  wliich  lie  is  justly  celebrated.  He  came  to  the  conclusion  that  the  body  was 
entirely  made  np  of  vessels.     lie  died  at  the  advanced  ajre  of  nin(;ty-lliree  years. 

t  Felix  Fontana,  an  anatomist  of  Tuscany.  His  "  Description  of  a  New  Canal  in 
the  Eye,"  was  published  in  1778,  in  a  letter  to  the  Professor  of  Anatomy  in  Upsal. 


CILIARY  PROCESSES RETINA. 


471 


the  centre,  and  have  the  power  of  dilating  the  pupil ;  and  circular, 
■which  surround  the  pupil  like  a  sphincter,  and  by  their  action  pro- 
duce contraction  of  its  area.     The 
posterior  layer  is  of  a  deep  purple  ^'g-  ^^"'• 

tint,  and   is   thence   named  uvea,  ■, 

from  its  resemblance  in  colour  to 
a  ripe  grape. 

The  Ciliary  processes  may  be 
seen  in  two  ways,  either  by  re- 
moving the  iris  from  its  attach- 
ment to  the  ciliary  ligament,  when 
a  front  view  of  the  processes  will 
be  obtained,  or  by  making  a  trans- 
verse section  through  the  globe  of 
the  eye,  when  they  may  be  exa- 
mined from  behind,  as  in  fig.  167. 

The  ciliary  processes  consist  of 
a  number  of  triangular  folds,  formed 

apparently  by  the  plaiting  of  the  internal  layer  of  the  choroid.  They 
are,  according  to  Zinn,  about  sixty  in  number,  and  may  be  divided 
into  large  and  small,  the  latter  being  situated  in  the  spaces  between 
the  former.  The  periphery  is  connected  with  the  ciliary  liga- 
ment, and  is  continuous  with  the  internal  layer  of  the  choroid.  The 
central  border  is  free,  and  rests  against  the  circumference  of  the 
lens.  The  anterior  surface  corresponds  with  the  uvea ;  the  poste- 
rior receives  the  folds  of  the  zonula  ciliaris  between  its  processes, 
and  thus  establishes  a  connexion  between  the  choroid  and  the  third 
tunic  of  the  eye.  The  ciliary  processes  are  covered  with  a  thick 
layer  of  pigmentum  nigrum,  which  is  more  abundant  upon  them, 
and  upon  the  anterior  part  of  the  choroid,  than  upon  the  posterior. 
When  the  pigment  is  washed  off,  the  processes  are  of  a  whitish 
colour. 

3.  T/iii^d  tunic. — The  third  tunic  of  the  eye  is  the  retina,  which 
is  prolonged  forwards  to  the  lens  by  the  zonula  ciliaris. 

Dissection. — If  after  ihe  preceding  dissection  the  choroid  mem- 
brane be  carefully  raised  and  removed,  the  eye  being  kept  under 
water,  the  retina  may  be  seen  very  distinctly. 

The  Retina  is  composed  of  three  layers : 

External  or  Jacob's  membrane, 
Middle,  Nervous  membrane. 

Internal,       A'^ascular  membrane. 

Jacob's  membrane  is  extremely  thin,  and  is  seen  as  a  flocculent 
film  when  the  eye  is  suspended  in  water.     Examined  by  the  micro- 

*  Fig.  167.  The  anterior  segfment  of  a  transverse  section  of  the  globe  of  the  eye, 
seen  from  within.  1.  Tlie  divided  edge  of  the  three  tunics ;  sclerotic,  choroid  (the 
dark  layer,)  and  retina.  2.  The  pupil.  3.  The  iris,  the  surface  presented  to  viow  in 
this  section  being  the  uvea.  4.  The  ciliary  processes.  5.  The  scalloped  anterior  bor- 
der of  the  retina, 


AT-i 


RETINA — STRUCTDEE. 


Fig.  1( 


scope,  it  is  seen  to  be  composed  of  granules  having  a  tesselated  ar- 
rangement.    Dr.  Jacob  considers  it  to  be  a  serous  membrane. 

The  A''ervous  memhrane  is  the  expansion  of  the  optic  nerve,  and 
forms  a  thin  semi-transparent  bluish  white  layer,  which  envelopes 
the  vitreous  humour,  and  extends  forwards  to  the  commencement 
of  the  ciliary  processes,  where  it  terminates  in  an  abrupt  scalloped 
margin. 

This  layer  has  been  observed  by  Treviranus  to  be  composed  of 
cylindrical  fibres,  which  proceed  from  the  optic  nerve  and  bend 
abruptly  inwards,  near  their  termination,  to  form  the  internal  papil- 
lary layer,  which  lies  in  contact  with  the  hyaloid  membrane;  each 
fibre  constituting  by  its  extremity  a  distinct  papilla. 

The  Vascular  membrane  consists  of  the  ramifications  of  a  minute 
artery,  the  arteria  centralis  retinae,  and  its  accompanying  vein ;  the 

artery  pierces  the  optic  nerve,  and 
enters  the  globe  of  the  eye  through 
the  porus  opticus  in  the  centre  of 
the  lamina  cribrosa.  This  artery 
may  be  seen  very  distinctly  by  mak- 
ing a  transverse  section  of  the  eye- 
ball. Its  branches  are  continuous 
anteriorly  with  the  zonula  ciliaris. 

This  vascular  layer  forms  distinct 
sheaths  for  the  nervous  papiUce, 
which  constitute  the  inner  surface 
of  the  retina. 

In  the  centre  of  the  posterior  part 
of  the  globe  of  the  eye  the  retina 
presents  a  circular  spot,  which  is 
called  the  foramen  of  Soemmering  ;*  it  is  surrounded  by  a  yellow 
halo,  the  limhus  hiieus,  and  is  frequently  obscured  by  an  elliptical 
fold  of  the  retina,  which,  from  its  constancy  of  appearance,  has 
been  regarded  as  a  normal  condition  of  the  membrane.  The  term 
foramen  is  misapplied  to  this  spot,  for  the  vascular  layer  and  the 
membrani  Jacobi  are  continued  across  it;  the  nervous  substance 
alone  appearing  to  be  deficient.  It  exists  only  in  animals  having 
the  axis  of  the  eyeballs  parallel  with  each  other,  as  man,  quadrumana, 
and  some  saurian  reptiles,  and  is  said  to  give  passage  to  a  small 
lymphatic  vessel. 

Fig.  168.  The  posterior  segment  of  the  transverse  section  of  the  globe  of  the  eye, 
seen  from  within.  1.  The  divided  edge  of  the  three  tunics.  The  membrane  covering 
the  whole  internal  surface  is  the  retina.  2.  The  entrance  of  the  optic  nerve  with  the 
artnria  centralis  retina)  piercing  its  centre.  3,3.  TJie  ramifications  of  the  arteria  cen- 
tralis. 4,  Tlie  foramen  of  Soemmering,  in  the  centre  of  the  axis  of  the  eye;  the  shade 
from  the  sides  of  tlie  section  obscures  the  limbus  lutcus  which  surrounds  it.  5.  A  fold 
of  the  retina,  which  generally  obscures  the  foramen  of  Soemmering  after  the  eye  has 
been  opened. 

*  Sirnuol  Thomas  Soemmering  is  celebrated  for  the  beantiful  and  accurate  plates 
which  accompany  his  works.  Tlie  account  "  Dc  Foramine  Centrali  Retinae  Humanse, 
Limbo  Lutco  cinclo,"  was  publi.shcd  in  1771),  in  tlic  Commcntatiunes  Soc.  Reg,  Sclent. 
Goltinsensis, 


HUMOURS  OF  THE  EYE.  473 

The  zonula  ciliaris  (zonula  of  Zinn)*  is  a  thin  vascular  layer 
which  connects  the  anterior  margin  of  the  retina  with  the  anterior 
surface  of  the  lens  near  to  its  circumference.  It  presents  upon  its 
surface  a  number  of  small  folds  corresponding  with  the  cihary  pro- 
cesses, between  which  they  are  received.  These  processes  are 
arranged  in  the  form  of  rays  around  the  lens,  and  the  spaces  be- 
tween them  are  stained  by  the  pigmentum  nigrum  of  the  cihary 
processes.  They  derive  their  vessels  from  the  vascular  layer  of  the 
retina.  The  under  surface  of  the  zonula  is  in  contact  with  the 
hyaloid  membrane,  and  around  the  lens  forms  the  anterior  fluted 
wall  of  the  canal  of  Petit. 

The  connexion  between  these  folds  and  the  ciliary  processes  may 
be  very  easily  demonstrated  by  dividing  an  eye  transversely  into 
two  portions,  then  raising  the  anterior  half,  and  allowing  the  vitreous 
humour  to  separate  from  its  attachment  by  its  own  weight.  The 
folds  of  the  zonula  will  then  be  seen  to  be  drawn  out  fi-om  between 
the  folds  of  the  ciliary  processes. 

Humours. — The  Aqueous  humour  is  situated  in  the  anterior  and 
posterior  chambers  of  the  eye;  it  is  a  weakly  albuminous  fluid,  hav- 
ing an  alkaline  reaction,  and  a  specific  gravity  very  little  greater 
than  distilled  water.  According  to  Petit,  it  scarcely  exceeds  four 
or  five  grains  in  weight. 

The  anterior  chamber  is  the  space  intervening  between  the  cornea 
in  front  and  the  iris  and  pupil  behind. 

The  posterior  chamber  is  the  narrow  space,  less  than  half  a  line 
in  depth,-]-  bounded  by  the  posterior  surface  of  the  iris  and  pupil  in 
front,  and  by  the  ciliary  processes,  zonula  ciliaris,  and  lens  behind. 

The  two  chambers  are  lined  by  a  thin  layer,  the  secreting  mem- 
brane of  the  aqueous  humour. 

The  Vitreous  humour  forms  the  principal  bulk  of  the  globe  of  the 
eye.  It  is  an  albuminous  fluid  resembling  the  aqueous  humour  en- 
closed in  a  delicate  membrane,  the  hyaloid,  which  sends  processes 
into  its  interior,  forming  cells  in  which  the  humour  is  retained.  A 
small  artery  may  sometimes  be  traced  through  the  centre  of  the 
vitreous  humour  to  the  capsule  of  the  lens;  it  is  surrounded  by  a 
tubular  sheath  of  the  hyaloid  membrane.  This  vessel  is  easily  in- 
jected in  the  fcetus. 

The  Crystalline  humour  or  lens  is  situated  immediately  behind 
the  pupil,  and  is  surrounded  by  the  ciliary  processes,  which  slightly 
overlap  its  margin.  It  is  more  convex  on  the  posterior  than  on  the 
anterior  surface,  and  is  embedded  in  the  anterior  part  of  the  vitreous 
humour,  from  which  it  is  separated  by  the  hyaloid  membrane.  It 
is  invested  by  a  peculiarly  transparent  and  elastic  membrane,  the 

*  John  Gottfried  Zinn,  Professor  of  Anatomy  in  Gottingen ;  his  "  Descriptio  Anato- 
mica  Oculi  Humani,"  was  puUished  in  1755;  with  excellent  plates.  It  was  republislicd 
by  Wrisberg  in  1780. 

t  Winslow  and  Lieutaud  thought  the  iris  to  be  in  contact  with  the  lens ;  it  frequent- 
ly adheres  to  the  capsule  of  the  latter  in  iritis.  The  depth  of  the  posterior  clianibcr  is 
greater  in  old  than  in  young  persons. 

40* 


474  CBySTALLlNE  HUMOUR STRUCTURE. 

capsule  of  the  lens,  which  contains  a  small  quantity  of  fluid  called 
liquor  Morgagni*  and  is  retained  in  its  place  by  the  attachment  of 
the  zonula  cilia ris.  Dr.  Jacob  is  of  opinion  that  the  lens  is  con- 
nected to  its  capsule  by  means  of  cellular  tissue,  and  that  the  liquor 
Morgagni  is  the  result  of  a  cadaveric  change. 

The  Lens  consists  of  concentric  layers,  of  which  the  external 
are  soft,  the  next  firmer,  and  the  central  form  a  hardened  nucleus. 
These  layers  are  best  demonstrated  by  boiling,  or  by  immersion  in 
alcohol,  when  they  separate  easily  from  each  other.  Another  divi- 
sion of  the  lens  takes  place  at  the  same  time  :  it  splits  into  three  tri- 
angular segments,  which  have  the  sharp  edge  directed  towards  the 
centre,  and  the  base  towards  the  circumference.  The  concentric 
lamellae  are  composed  of  minute  parallel  fibres,  which  are  united 
with  each  other  by  means  of  scalloped  borders ;  the  convexity  on  the 
one  border  fitting  accurately  the  concave  scallop  upon  the  other. 

Immediately  around  the  circumference  of  the  lens  is  a  triangular 
canal,  the  canal  of  Petit,^  about  a  line  and  a  half  in  breadth.  It  is 
bounded  in  front  by  the  flutings  of  the  zonula  ciliaris;  behind  by 
the  hyaloid  membrane;  and  within  by  the  border  of  the  lens. 

The  Vessels  of  the  globe  of  the  eye  are  the  long,  and  short,  and 
anterior  ciliary  arteries,  and  the  arteria  centralis  retinse.  The  long 
ciliary  arteries,  two  in  number,  pierce  the  posterior  part  of  the  scle- 
rotic, and  pass  forward  on  each  side,  between  that  membrane  and 
the  choroid,  to  the  ciliary  ligament,  where  they  divide  into  two 
branches,  which  are  distributed  to  the  iris.  The  shorL  ciliary  arteries 
pierce  the  posterior  part  of  the  sclerotic  coat,  and  are  distributed  to 
the  internal  layer  of  the  choroid  membrane.  The  anterior  ciliary 
are  branches  of  the  muscular  arteries.  They  enter  the  eye  through 
the  anterior  part  of  the  sclerotic,  and  are  distributed  to  the  iris.  It 
is  the  increased  number  of  these  arteries  in  iritis  that  forms  the 
peculiar  red  zone  around  the  circumference  of  the  cornea. 

The  arteria  centralis  retincB  enters  the  optic  nerve  at  about  half 
an  inch  from  the  globe  of  the  eye,  and  passing  through  the  porus 
opticus  is  distributed  upon  the  inner  surface  of  the  retina,  forming 
its  vascular  layer;  one  branch  pierces  the  centre  of  the  vitreous 
humour,  and  supplies  the  capsule  of  the  lens. 

The  Nerves  of  the  eyeball  are  the  optic,  two  ciliary  nerves  from 
the  nasal  branch  of  the  ophthalmic,  and  the  ciliary  nerves  from  the 
ciliary  ganglion. 

Observations. — The  sclerotic  is  a  tunic  of  protection,  and  the 
cornea  a  medium  for  the  transmission  of  light.  The  choroid  sup- 
ports the  vessels  destined  for  the  nourishment  of  the  eye,  and  by  its 
pigmentum  nigrum  absorbs  all  loose  and  scattered  rays  that  might 
confuse  the  image  impressed  upon  the  retina.     The  iris,  by  means 

•  John  Baptist  Morg-ngril  was  born  in  1682.  He  was  appointed  Professor  of  Medi- 
cine in  Bolo^rna,  and  published  the  first  part  of  his  "Adversaria  Anatomica,"  in  1706. 
He  dind  in  )771, 

t  .lohn  Louis  Petit,  a  celebrated  French  surgeon:  he  published  several  surgical  and 
anatomical  Essays,  in  the  early  part  of  the  18th  century.     He  died  in  1750. 


APPENDAGES  OF  THE  EYE.  475 

of  its  powers  of  expansion  and  contraction,  regtlales  the  quantity 
of  light  admitted  through  the  pupil.  If  the  iris  be  thin,  and  the  rays 
of  light  pass  through  its  substance,  they  are  immediately  absorbed 
by  the  uvea;  and  if  that  layer  be  insufficient,  they  are  taken  up  by 
the  black  pigment  of  the  ciliary  processes. 

In  Albinoes,  where  there  is  an  absence  of  pigmentum  nigrum,  the 
rays  of  light  traverse  the  iris  and  even  the  sclerotic,  and  so  over- 
W'helm  the  eye  wnh  light,  that  sight  is  destroyed,  except  in  the 
dimness  of  evening  or  at  night. 

In  the  manufacture  of  optical  instruments  care  is  taken  to  colour 
their  interior  black,  with  the  same  object,  the  absorption  of  scat- 
tered rays. 

The  transparent  lamellated  cornea  and  the  humours  of  the  eye 
have  for  their  office  the  refraction  of  the  rays  in  such  proportion  as 
to  direct  the  image  in  the  most  favourable  manner  upon  the  retina. 
Where  the  refracting  medium  is  too  great,  as  in  over  convexity  of 
the  cornea  and  lens,  the  image  falls  short  of  the  retina  (myopia, 
near-sightedness);  and  where  it  is  too  little  the  image  is  thrown 
beyond  the  nervous  membrane  (presbyopia,  far-sightedness.) 

These  conditions  are  rectified  by  the  use  of  spectacles,  which 
provide  a  differently  refracting  medium  externally  to  the  eye,  and 
thereby  correct  the  transmission  of  light. 

APPENDAGES   OF    THE    EYE. 

The  Appendages  of  the  eye  {tutamina  oculi)  are  the  eyebrows, 
eyelids,  eyelashes,  conjunctiva,  caruncula  lachrymalis,  and  the 
lachrymal  apparatus. 

The  Eyebrows  {swpercUia)  are  tv;o  projecting  arches  of  integu- 
ment covered  with  short  thick  hairs,  which  form  the  upper  boundary 
of  the  orbits.  They  are  connected  beneath  with  the  orbiculares, 
occipito-frontales,  and  corrugatores  superciliorum  muscles;  their 
use  is  to  shade  the  eyes  from  a  too  vivid  light,  or  protect  them 
from  particles  of  dust  and  moisture  floating  over  the  forehead. 

The  Eyelids  {palpebi'ce)  are  two  valvular  layers  placed  in  front 
of  the  eye,  serving  to  defend  it  from  injury  by  their  closure.  When 
drawn  open  they  leave  between  them  an  elliptical  space,  the  angles 
of  which  are  called  canthi.  The  outer  canthus  is  formed  by  the 
meeting  of  the  two  lids  at  an  acute  angle.  The  inner  canthus  is 
prolonged  for  a  short  distance  inwards  towards  the  nose,  and  a 
triangular  space  is  left  between  the  lids  in  this  situation,  which  is 
called  the  Incus  lachrymalis.  At  the  commencement  of  the  lacus 
lachrymalis  upon  each  of  the  two  lids  is  a  small  angular  projection, 
the  lachrymal  papilla  or  tubercle ;  and  at  the  apex  of  each  papilla 
is  a  small  orifice  (punctum  lachrymale),  the  commencement  of  the 
lachrymal  canal. 

The  eyelids  have,  entering  into  their  structure,  ivtegument,  orbicu- 
laris muscle,  tarsal  cartilages,  Meibomian  glands,  and  conjunctiva. 

The  tegumentary  cellular  tissue  of  the  eyelids  is  remarkable  for 
its  looseness  and  for  the  entire  absence  of  adipose  substance.     It  is 


,476  TAKSI — MEIBOMIAN  GLANDS. 

particularly  liable  to  serous  infiltration.  The  fibres  of  the  orbicu- 
laris muscle  covering  the  eyelids,  are  extremely  thin  and  pale. 

The  Tarsal  cartilages  are  two  thin  lamellae  of  fibro-cartilage 
about  an  inch  in  length,  which  give  form  and  support  to  the  eyelids. 
The  superior  is  of  a  semilunar  form,  about  one-third  of  an  inch  in 
breadth  at  its  middle,  and  tapering  to  each  extremity.  Its  lower 
border  is  broad  and  flat,  its  upper  is  thin,  and  gives  attachment  to 
the  levator  palpebrse  and  to  the  fibrous  membrane  of  the  lids. 

The  Inferior  fibro-cartilage  is  an  elliptical  band,  narrower  than  the 
superior,  and  situated  in  the  substance  of  the  lower  lid.  Its  upper 
border  is  flat,  and  corresponds  with  the  flat  edge  of  the  upper  car- 
tilage. The  lower  is  held  in  its  place  by  the  fibrous  membrane. 
At  the  inner  canthus  the  tarsal  cartilages  terminate  at  the  com- 
mencement of  the  lachrymalis,  and  are  attached  to  the  margin  of 
the  orbit  by  the  tendo  oculi.  At  their  outer  extremity  they  termi- 
nate at  a  short  distance  from  the  angle  of  the  canthus,  and  are 
retained  in  their  position  by  means  of  a  decussation  of  the  fibrous 
structure  of  the  broad  tarsal  ligament,  called  the  external  palpebral 
ligament. 

The  Fibrous  membrane  of  the  lids  is  firmly  attached  to  the  perios- 
teum, around  the  margin  of  the  orbit,  by  its  circumference,  and  to 
the  tarsal  cartilages  by  its  central  margin.  It  is  thick  and  dense  on 
the  outer  half  of  the  orbit,  but  becomes  thin  to  its  inner  side.  Its 
use  is  to  retain  the  tarsal  cartilages  in  their  place,  and  give  support 
to  the  lids;  hence  it  has  been  named  the  broad  tarsal  ligament. 

The  Meibomian  glands*  are  embedded  in  the  internal  surface  of 
the  cartilages,  and  are  very  distinctly  seen  on  examining  the  inner 
surface  of  the  lids.  They  have  the  appearance  of  parallel  strings 
of  pearls,  about  thirty  in  number  in  the  upper  cartilage,  and  some- 
what fewer  in  the  lower;  they  open  by  minute  foramina  upon  the 
edges  of  the  lids.  They  correspond  in  length  with  the  breadth  of 
the  cartilage,  and  are  consequently  longer  in  the  upper  than  in  the 
lower  lid. 

Each  gland  consists  of  a  single  lengthened  follicle  or  tube,  into 
which  a  number  of  small  clustered  follicles  open;  the  latter  are  so 
numerous  as  almost  to  conceal  the  tube  by  which  the  secretion  is 
poured  out  upon  the  margin  of  the  lids.  They  are  figured,  after  a 
very  careful  examination,  in  Dr.  Quain's  "  Elements  of  Anatomy." 
Occasionally  an  arch  is  formed  between  two  of  them,  as  is  seen  in 
that  figure,  and  produces  a  very  gracefijl  appearance. 

The  edges  of  the  eyelids  are  furnished  with  a  triple  row  of  long 
thick  hairs,  which  curve  upwards  from  the  upper  lid,  and  down- 
wards from  the  lower,  so  that  they  may  not  interlace  with  each 
other  in  the  closure  of  the  eyelids,  and  prove  an  impediment  to  the 
opening  of  the  eyes.  These  are  the  eyelashes  {cilia),  important 
organs  of  defence  to  the  sensitive  surface  of  so  delicate  an  organ 
as  the  eye. 

•  Henry  Meibomius,  "de  Vasis  Palpebrarum  Novis,"  1666. 


LACHRYMAL  API'AHATUS.  477 

The  Covjunctiva  is  the  mucous  membrane  of  the  eye.  It  covers 
the  whole  ot'its  anterior  surface,  and  is  then  reflected  upon  the  lids 
so  as  to  form  their  internal  layer.  The  duplicatures  formed  between 
the  globe  of  the  eye  and  the  lids  are  called  the  superior  <xndi  inferior 
palpebral  siiiuses,  of  which  the  former  is  much  deeper  than  the  in- 
ferior. Where  it  covers  the  cornea  the  conjunctiva  is  very  thin 
and  closely  adherent,  and  no  vessels  can  be  traced  into  it.  Upon 
the  sclerotica  it  is  thicker  and  less  adherent,  and  to  the  inner  sur- 
face of  the  lids  is  very  closely  connected,  and  is  exceedingly  vas- 
cular. It  is  continuous  with  the  general  gastro-pulmonary  mucous 
membrane,  and  sympathizes  in  its  affections,  as  may  be  observed  in 
various  diseases.  From  the  surface  of  the  eye  it  may  be  traced 
through  the  lachrymal  gland ;  along  the  edges  of  the  lids  it  is  con- 
tinuous with  the  mucous  lining  of  the  Meibomian  glands,  and  at  the 
inner  angle  of  the  eye  may  be  followed  through  the  lachrymal 
canals  into  the  lachrymal  sac,  and  thence  downwards  through  the 
nasal  duct  into  the  inferior  meatus  of  the  nose. 

This  membrane  is  coated  with  a  lamellated  epithelium  composed 
of  vesicles  and  flattened  scales,  with  central  nuclei. 

The  Caruncula  lachrymalis  is  the  small  reddish  body  which  oc- 
cupies the  lacus  lachrymalis  at  the  inner  canthus  of  the  eye.  In 
health  it  presents  a  bright  pink  tint ;  in  sickness  it  loses  its  colour 
and  becomes  pale.  It  consists  of  an  assemblage  of  follicles  similar 
to  the  Meibomian  glands,  embedded  in  a  fibro-cartilaginous  tissue, 
and  is  the  source  of  the  whitish  secretion  which  so  constantly  forms 
at  the  inner  angle  of  the  eye.  It  is  covered  with  minute  hairs 
which  are  sometimes  so  long  as  to  be  distinctly  visible  to  the  naked 
eye. 

'  Immediately  to  the  outer  side  of  the  caruncula  is  a  slight  dupli- 
cature  of  the  conjunctiva,  called  plica  semilunaris,  which  contains 
a  rninute  plate  of  cartilage,  and  is  the  rudiment  of  the  third  lid  of 
animals,  the  membrana  niclitans  of  birds. 

Vessels  and  nerves. — The  palpebrae  are  supplied  internally  with 
arteries  from  the  ophthalmic,  and  externally  from  the  facial  and 
transverse  facial.  Their  nerves  are  branches  of  the  fifth  and  of  the 
facial. 

LACHRYMAL    APPARATUS. 

The  Lachrymal  apparatus  consists  of  the  lachrymal  gland  with 
its  excretory  ducts;  the  puncta  lachrymalia,  and  lachrymal  canals; 
the  lachrymal  sac  and  nasal  duct. 

The  Lachrymal  gland  is  situated  at  the  upper  and  outer  angle  of 
the  orbit,  and  consists  of  two  portions,  orbital  and  palpebral.  The 
orbital  portion,  about  three  quarters  of  an  inch  in  length,  is  flattened 
and  oval  in  shape,  and  occupies  the  lachrymal  fossa  in  the  orbital 
plate  of  the  frontal  bone;  being  in  contact  with  the  periosteum,  to 
which  it  is  closely  connected  by  its  upper  and  convex  surface ;  being 
in  relation  with  the  globe  of  the  eye,  and  with  the  superior  and  ex- 
ternal rectus  by  its  inferior  or  concave  surface ;  and  with  the  broad 


478  ORGAN  OF  HEAKIiSG. 

tarsal  ligament  by  its  anterior  border.  By  its  posterior  border  it 
receives  its  vessels  and  nerves.  The  fulpehral portion,  smaller  than 
the  preceding,  is  situated  in  the  upper  eyelid,  extending  downwards 
to  the' superior  margin  of  the  tarsal  cartilage.  It  is  continuous  with 
the  orbital  portion  above,  and  is  enclosed  in  an  investment  of  dense 
fibrous  membrane.  The  secretion  of  the  lachrymal  gland  is  con- 
veyed away  by  ten  or  twelve  small  ducts  which  run  for  a  short 
distance  beneath  the  conjunctiva,  and  open  upon  its  surface  by  a 
series  of  pores  about  one-twentieth  of  an  inch  apart,  situaied  in  a 
curved  line  a  little  above  the  upper  border  of  the  tarsal  cartilage. 

Lachrymal  canals. — The  lachrymal  canals  commence  at  the 
minute  openings,  puncta  lachrymalia,  seen  upon  the  lachrymal 
papillog  of  the  lids  at  the  outer  extremity  of  the  lacus  lachrymalis, 
and  proceed  inwards  to  the  lachrymal  sac,  where  they  terminate 
beneath  a  valvular  semilunar  fold  of  the  lining  membrane  of  the 
sac.  The  superior  duct  at  first  ascends,  and  then  turns  suddenly 
inwards  towards  the  sac,  forming  an  abrupt  angle.  The  inferior 
duct  forms  the  same  kind  of  angle,  by  descending  at  first,  and  then 
turning  abruptly  inwards.  They  are  dense  and  elastic  in  structure, 
and  remain  constantly  open,  so  that  they  act  like  capillar}^  tubes  in 
absorbing  the  tears  from  the  surface  of  the  eye.  The  two  fasciculi 
of  the  tensor  tarsi  muscle  are  inserted  into  these  ducts,  and  serve 
to  draw  them  inwards. 

The  Lachrymal  sac  is  the  upper  extremity  of  the  nasal  duct,  and 
is  scarcely  more  dilated  than  the  rest  of  the  canal.  It  is  lodged  in 
the  groove  of  the  lachrymal  bone,  and  is  often  distinguished  inter- 
nally from  the  nasal  duct  by  a  semilunar  or  circular  valve.  It  con- 
sists of  mucous  membrane,  but  is  covered  in  and  retained  in  its  place 
by  a  fibrous  expansion,  derived  from  the  tendon  of  the  orbicularis, 
which  is  inserted  into  the  ridge  on  the  lachrymal  bone :  it  is  also 
covered  by  the  tensor  tarsi  muscle,  which  arises  from  the  same  ridge, 
and  in  its  action  upon  the  lachrymal  canals  may  serve  to  compress 
the  lachrymal  sac. 

The  JYasal  duct  is  a  short  canal  about  three  quarters  of  an  inch 
in  length,  directed  downwards,  backwards,  and  a  little  outwards  to 
the  inferior  meatus  of  the  nose,  where  it  terminates  by  an  expanded 
orifice.  It  is  lined  by  mucous  membrane,  which  is  continuous  with 
the  Conjunctiva  above,  and  with  the  pituitary  membrane  of  the  nose 
below.  Obstruction  from  inflammation  and  suppuration  of  this  duct 
constitutes  the  disease  called  fistula  lachrymalis. 

Vessals  and  nerves. — The  lachrymal  gland  is  supplied  with  blood 
by  the  lachrymal  branch  of  the  ophthalmic  artery,  and  with  nerves 
by  the  lachrymal  branch  of  the  ophthalmic  and  orbital  branch  of 
the  superior  maxillary. 


I    dl 


THE    ORGAN    OF    HEARING. 

■^^  The  Ear  is  composed  of  three  parts.     1.  External  ear.     2.  Mid- 
dle ear,  or  tympanum.     3.  Internal  ear,  or  labyrinth. 

The  External  Ear  consists  of  two  portions,  the  pinna  and 


ORGAN  OF  HEARING.  479 

meatus;  the  former  representing  a  kind  of  funnel  which  collects  the 
vibrations  of  the  atmosphere,  called  sounds,  and  the  latter  a  tube 
which  conveys  the  vibrations  to  the  tympanum. 

The  Pinna  presents  a  number  of  folds  and  hollows  upon  its  sur- 
face, which  have  different  names  assigned  to  them.  Thus  the  ex- 
ternal folded  margin  is  called  the  helix  (s>^'f,  a  fold).  The  eleva- 
tion parallel  to  and  in  front  of  the  helix  is  called  antihelix  (avr/,  op- 
posite.) The  pointed  process,  projecting  like  a  valve  over  the  open- 
ing of  the  ear  from  the  face,  is  called  the  tragus  (rpa^o?,  a  goat), 
probably  from  being  sometimes  covered  with  bristly  hair  like  that 
of  a  goat;  and  a  tubercle  opposite  to  this  is  the  antitragus.  The 
lower  dependent  and  fleshy  portion  of  the  pinna  is  the  hbuhis.  The 
space  between  the  helix  and  antihelix  is  named  the  fossa  in- 
nominata. 

Another  depression  is  observed  at  the  upper  extremity  of  the  anti- 
helix, which  bifurcates  and  leaves  a  triangular  space  between  its 
branches  called  the  scaphoid  fossa  :  and  the  large  central  space  to 
which  all  the  channels  converge  is  the  concha,  which  opens  directly 
into  the  meatus. 

The  pinna  is  composed  of  integument,  fibro-carlilage,  ligaments, 
and  muscles. 

The  Integument  is  thin,  and  closely  connected  with  the  fibro-car- 
tilage. 

The  Fibro-cartilage,  gives  form  to  the  pinna,  and  is  folded  so  as 
to  produce  the  various  convexities  and  grooves  which  have  been 
described  upon  its  surface.  The  helix  commences  in  the  concha, 
and  partially  divides  that  cavity  into  two  parts;  on  its  anterior  bor- 
der is  a  tubercle  for  the  attachment  of  the  atrahens  aurem  muscle, 
and  a  little  above  this  a  small  vertical  fissure,  the  fissure  of  the 
helix.  The  termination  of  the  helix  and  antihelix  forms  a  length- 
ened process,  the  processus  caudatus,  which  is  separated  from  the 
concha  by  an  extensive  fissure.  Upon  the  anterior  surface  of  the 
tragus  is  another  fissure,  the  fissure  of  the  tragus,  and  in  the  lobulus 
the  fibro-cartilage  is  wholly  deficient.  The  fibro-cartilage  of  the 
meatus,  at  the  upper  and  anterior  part  of  the  cylinder,  is  divided 
from  the  concha  by  a  fissure  which  is  closed  in  the  entire  ear  by 
ligamentous  fibres;  it  is  firmly  attached  at  its  termination  to  the 
processus  auditorius. 

The  Ligaments  of  the  external  ear  are  those  which  attach  the 
pinna  to  the  side  of  the  head,  viz.  the  anterior,  posterior,  and  liga- 
ment of  the  tragus;  and  those  of  the  fibro-cartilage,  which  serve  to 
preserve  its  folds  and  connect  the  opposite  margins  of  the  fissures. 
The  latter  are  two  in  number, — the  ligament  between  the  concha 
and  the  processus  caudatus,  and  the  broad  hgament  w-hich  extends 
from  the  upper  margin  of  the  fibro-cartilage  of  the  tragus  to  the 
helix,  and  completes  the  meatus. 

The  proper  Muscles  of  the  Pinna  are  the — 


4S0  TYMPANUM CONTENTS. 

Major  helicis, 
Minor  helicis, 
Tragicus, 
Antitragicus, 
Transversus  auriculae. 

The  Major  helicis  is  a  narrow  band  of  muscular  fibres  situated 
upon  the  anterior  border  of  the  helix,  just  above  the  tragus. 

The  Minor  helicis  is  placed  upon  the  posterior  border  of  the 
helix,  at  its  commencement  in  the  fossa  of  the  concha. 

The  Tragicus  is  a  thin  quadrilateral  layer  of  muscular  fibres, 
situated  upon  the  tragus. 

The  Antitragicus  arises  from  the  antitragus,  and  is  inserted  into 
the  posterior  extremity,  or  processus  caudatus  of  the  helix. 

The  Transversus  auriculcB,  partly  tendinous  and  partly  muscular, 
extends  transversely  from  the  convexity  of  the  concha  to  that  of  the 
helix,  on  the  posterior  surface  of  the  pinna. 

These  muscles  are  rudimentary  in  the  human  ear,  and  deserve 
only  the  title  of  muscles  in  the  ears  of  animals.  Two  other  muscles 
are  described  by  Mr.  Tod,*  the  obliquus  auris  and  contractor  meatus, 
or  trago-helicus. 

The  Meatus  auditorius  is  a  canal,  partly  cartilaginous  and  partly 
osseous,  about  an  inch  in  length,  which  extends  inwards  and  a  little 
forwards  from  the  concha  to  the  tympanum.  It  is  narrower  in  the 
middle  than  at  each  extremity,  forms  an  oval  cylinder,  the  long 
diameter  being  vertical,  and  is  slightly  curved  upon  itself,  the  con- 
cavity looking  downwards. 

It  is  lined  by  an  extremely  thin  pouch  of  cuticle,  which,  when 
withdrawn  after  maceration,  preserves  the  form  of  the  meatus. 
Some  stiff  short  hairs  are  also  found  in  its  interior,  which  stretch 
across  the  tube,  and  prevent  the  ingress  of  insects  and  dust.  Be- 
neath the  cuiicle  are  a  number  of  small  ceruminous  follicles,  which 
secrete  the  wax  of  the  ear. 

Vessels  and  JVerves. — The  pinna  is  plentifully  supplied  with  arte- 
ries ;  by  the  anterior  auricular  from  the  temporal,  and  by  the  pos- 
terior auricular  from  the  external  carotid. 

Its  JVerves  are  derived  from  the  auricular  branch  of  the  fifth,  and 
from  the  auricularis  magnus  of  the  cervical  plexus. 

TvMPAivuM, — The  tympanum  is  an  irregular  bony  cavity,  com- 
pressed from  without  inwards,  and  situated  within  the  petrous  bone. 
It  is  bounded  externally  by  the  meatus  and  membrana  tympani;  in- 
ternally by  its  inner  wall;  and  in  its  circumference  by  the  petrous 
bone  and  mastoid  cells. 

The  Membrana  tympani  is  a  thin  and  semi-transparent  membrane 
of  an  oval  shape,  the  longer  diameter  being  nearly  vertical.  It  is 
inserted  into  a  groove  around  the  circumference  of  the  meatus  near 
to  its  termination,  and  is  placed  obliquely  across  the  area  of  that 
tube,  the  direction  of  the  obliquity  being  downwards  and  inwards. 

*  "The  Anatomy  and  Physiology  of  the  Organ  of  Hearing,"  by  David  Tod,  1832. 


TYMPANUM — CONTENTS.  481 

It  is  concave  towards  the  meatus,  and  convex  towards  the  tympa- 
num, and  is  composed  of  three  layers,  an  external  cuticular,  middle 
fibrous  and  muscular,  and  internal  mucous,  derived  from  the  mucous 
lining  of  the  tympanum. 

The  tympanum  contains  three  small  bones,  ossicula  audilus,  viz. 
the— 

Malleus, 

Incus, 

Stapes. 

The  Malleus  {hammer)  consists  of  a  head,  neck,  handle  {manu- 
brium), and  two  processes,  long  {'processus  gracilis),  and  short  {pro- 
cessus brevis).  The  manubrium  is  connected  to  the  membrana 
tympani  by  its  whole  length  extending  to  below  the  central  point 
of  that  membrane.  It  lies  beneath  its  mucous  layer,  and  serves  as 
a  point  of  attachment  to  which  the  radiating  fibres  of  the  fibrous 
layer  converge.  The  long  process  descends  to  a  groove  near  to 
the  fissura  Glaseri,  and  gives  attachment  to  the  laxator  tympani 
muscle.  Into  the  short  process  is  inserted  the  tendon  of  the  tensor 
tympani,  and  the  head  of  the  bone  articulates  with  the  incus. 

The  incits  {anvil)  is  named  from  an  imagined  resemblance  to  an 
anvil.  It  has  also  been  Ukened  to  a  bicuspid  tooth,  having  one  root 
longer,  and  widely  separated  from  the  other.  It  consists  of  two 
processes,  which  unite  nearly  at  right  angles,  and  at  their  junction 
form  a  flattened  body,  to  articulate  with  the  head  of  the  malleus. 
The  short  process  is  attached  to  the  margin  of  the  opening  of  the 
mastoid  cells  by  means  of  a  short  ligament ;  the  long  process  de- 
scends nearly  parallel  with  the  handle  of  the  malleus,  and  curves 
inwards,  near  to  its  termination.  At  its  extremity  is  a  small  glo- 
bular projection,  the  os  orbiculare,  which  is  a  distinct  bone  in  the 
foetus,  but  becomes  anchylosed  to  the  long  process  of  the  incus  in 
the  adult;  this  process  articulates  with  the  head  of  the  stapes. 

The  Stapes  is  shaped  like  a  stirrup,  to  which  it  bears  a  close  re- 
semblance. Its  head  articulates  with  the  os  orbiculare,  and  the  two 
branches  are  connected  by  their  extremities  with  a  flat  oval-shaped 
plate,  representing  the  foot  of  the  stirrup.  The  foot  of  the  stirrup  is 
received  into  the  fenestra  ovalis,  to  the  margin  of  which  it  is  con- 
nected by  means  of  a  circular  ligament;  it  is  in  contact,  by  its  sur- 
face, with  the  membrana  vestibuli,  and  is  covered  in  by  the  mucous 
lining  of  the  tympanum.  The  neck  of  the  stapes  gives  attachment 
to  the  stapedius  muscle. 

The  ossicula  auditus  are  retained  in  their  position  and  moved 
upon  themselves  by  means  of  ligaments  and  muscles. 

The  Ligaments  are  three  in  number:  the  ligament  of  the  head  of 
the  malleus,  which  is  attached  superiorly  to  the  upper  wnll  of  the 
tympanum ;  the  ligament  of  the  incus,  a  short  and  thick  band, 
which  serves  to  aUach  the  extremity  of  the  short  process  of  that 
bone  to  the  margin  of  the  opening  of  the  mastoid  cells;  and  the 
circular  ligament,  which  connects  the  margin  of  the  foot  of  the 

41 


482 


MUSCLES  OF  THE  TYMPANUM. 


stapes  with  the  circumference  of  the  fenestra  ovalis.  These  liga- 
ments have  been  described  as  muscles,  by  Mr.  Tod,  under  the 
names  of  superior  capitis  mallei,  obliquus  incudis  externus  poste- 
rior, and  musculus,  vel  structura  stapedius  inferior. 

Fig.  169. 


The  Muscles  of  the  tympanum  are  four  in  number,  the—' 

Tensor  tympani, 
Laxator  tympani, 
Laxator  tympani  minor, 
Stapedius. 

The  Tensor  tympani  (musculus  internus  mallei)  arises  from  the 
spinous  process  of  the  sphenoid,  from  the  petrous  portion  of  the 
temporal  bone,  and  from  the  Eustachian  tube,  and  passes  forwards 
in  a  distinct  canal,  separated  from  the  tube  by  the  processus  coch- 
leariformis,  to  be  inserted  into  the  handle  of  the  malleus,  imme- 
diately below  the  commencement  of  the  processus  gracilis. 

Fig.  169.  A  diagram  of  the  ear.  p.  Tlie  pinna,  t.  The  tympanum.  /.  The  laby- 
rinth. ].  The  upper  part  of  the  helix.  2.  The  antihelix.  3.  The  tragus.  4.  The 
antitragus.  5.  The  lobulus.  6.  The  concha.  7.  The  upper  part  of  the  fossa  innomi- 
nata.  8.  The  meatus.  9.  Tlie  membrana  tympani,  divided  by  the  section.  10.  The 
three  little  bones,  crossing  the  area  of  tiie  tympanum,  malleus,  incus,  and  stapes ;  the 
foot  of  the  stapes  blocks  up  the  fenestra  ovalis  upon  the  inner  wall  of  the  tympanum. 
11.  The  promontory.  12.  The  fenestra  rotunda;  the  dark  opening  above  the  ossicula 
leads  into  the  mastoid  colls.  13.  TJie  Eustachian  tube ;  the  little  canal  upon  this  tube 
contains  the  tensor  tympani  muscle  in  its  passage  to  tlie  tympanum.  14.  The  ves- 
tibule. 15.  The  three  semicircular  canals,  horizontal,  perpendicular,  and  oblique. 
16.  The  ampullce  upon  the  per])endicular  and  horizontal  Ciinals.  17.  The  cochlea. 
18.  A  depression  between  the  convexities  of  the  two  tubuli  vvliich  communicate  with 
the  tympanum  and  vestibule;  ihe  one  is  the  scala  tympani,  terminating  at  12;  the 
other  is  the  scala  vestibuli. 


OPENINGS  OF  THE  TYMPANUM.  483 

The  Laxator  tympani  (musculus  externus  mallei)  arises  from  the 
spinous  process  of  the  sphenoid  bone,  and  passes  through  an  open- 
ing in  the  fissura  Glaseri,  to  be  inserted  into  the  long  pro^cess  of  the 
malleus. 

The  Laxator  tympani  minor  arises  from  the  upper  margin  of  the 
meatus,  and  is  inserted  into  the  handle  of  the  malleus,  near  to 
the  processus  brevis.  This  is  regarded  as  a  ligament  by  some 
anatomists. 

The  Stapedius  arises  from  the  interior  of  the  pyramid,  and 
escapes  from  its  summit  to  be  inserted  into  the  neck  of  the  stapes. 

The  openings  in  the  tympanum  are  ten  in  number,  jive  large  and 
Jive  small;  they  are — 

Large  Openings.  Small  Openings. 

Meatus  auditorius,  Entrance  of  the  chorda  tympani. 

Fenestra  ovalis.  Exit  of  the  chorda  tympani, 

Fenestra  rotunda,  For  the  laxator  tympani. 

Mastoid  cells.  For  the  tensor  tympani, 

Eustachian  tube.  For  the  stapedius. 

The  opening  of  the  meatus  auditorius  has  been  previously 
described. 

The  Fenestra  ovalis  (fenestra  vestibuli),  is  a  reniform  opening, 
situated  at  the  bottom  of  a  small  oval  fossa  (the  pelvis  ovalis),  in 
the  upper  part  of  the  inner  wall  of  the  tympanum,  directly  opposite 
the  meatus.  The  long  diameter  of  the  fenestra  is  directed  horizon- 
tally, and  its  convex  borders  upwards.  It  is  the  opening  of  com- 
munication between  the  tympanum  and  the  vestibule,  and  is  closed 
by  the  foot  of  the  stapes  and  by  the  lining  membranes  of  both 
cavities. 

The  Fenestra  rotunda  (fenestra  cochlece)  is  somewhat  triangular 
in  its  form,  and  situated  in  the  inner  wall  of  the  tympanum,  below 
and  rather  posteriorly  to  the  fenestra  ovalis,  from  which  it  is  sepa- 
rated by  a  bony  elevation,  called  the  promontory.  It  serves  to 
establish  a  communication  between  the  tympanum  and  the  cochlea. 
In  the  fresh  subject  it  is  closed  by  a  proper  membrane,  as  well  as 
by  the-  lining  of  both  cavities. 

The  Mastoid  cells  are  very  numerous,  and  occupy  the  whole  of 
the  interior  of  the  mastoid  process,  and  part  of  the  petrous  bone. 
They  communicate  by  a  large  irregular  opening  with  the  upper  and 
posterior  circumference  of  the  tympanum. 

The  Eustachian  tube  is  a  canal  of  communication  extending 
obliquely  between  the  pharynx  and  the  anterior  circumference  of 
the  tympanum.  In  structure  it  is  partly  fibro-cartilaginous  and 
partly  osseous,  is  broad  and  expanded  at  its  pharyngeal  extremity, 
and  narrow  and  compressed  at  the  tympanum. 

The  smaller  openings  serve  for  the  transmission  of  the  chorda 
tympani  nerve,  and  three  of  the  muscles  of  the  tympanum. 

The  opening  by  which  the  chorda  tympani  enters  the  tympanum, 


484  OPENINGS  OF  THE  TYMPANUM. 

is  near  the  root  of  the  pyramid,  at  about  the  middle  of  the  posterior 
wall. 

The  opening  of  exit  for  the  chorda  tympani  is  at  the  fissura  Glaseri 
in  the  anterior  loull  of  the  tympanum. 

The  opening  for  the  laxator  tympa7ii  mnscle  is  also  situated  in  the 
fissura  Glaseri,  in  the  anterior  ivall  of  the  tympanum. 

The  opening  for  the  tensor  tympani  muscle  is  in  ihe  inner  wall, 
immediately  above  the  opening  of  the  Eustachian  tube. 

The  opening  for  the  stapedius  muscle  is  at  the  apex  of  a  conical 
bony  eminence,  called  the  pyramid,  which  is  situated  on  the  poste- 
rior wall  of  the  tympanum,  immediately  behind  the  fenestra  ovalis. 

Directly  above  the  fenestra  ovalis  is  a  rounded  ridge  formed  by 
the  projection  of  the  aqucediictus  Fallopii. 

Beneath  the  fenestra  ovalis  and  separating  it  from  the  fenestra 
rotunda  is  the  promontory,  a  rounded  prominence  formed  by  the 
projection  of  the  first  turneof  the  cochlea.  It  is  channeled  upon 
its  surface  by  three  small  grooves,  which  lodge  the  three  tympanic 
branches  of  Jacobson's  nerve. 

The  Foramina  and  processes  of  the  tympanum  may  be  arranged, 
according  to  their  situation,  into  four  groups. 

1.  In  the  External  wall  is  the  meatus  auditorius,  closed  by  the 
memhrani  tympani. 

2.  In  the  Inner  wall,  from  above  downwards,  are  the — 

Opening  for  the  tensor  tympani. 

Ridge  of  the  aqueeductus  Fallopii, 

Fenestra  ovalis. 

Promontory, 

Grooves  for  Jacobson's  nerve, 

Fenestra  rotunda. 

3.  In  the  Posterior  wall  are  the — 

Opening  of  the  mastoid  cells. 

Pyramid, 

Opening  for  the  stapedius, 

Apertura  chordae  (entrance). 

4.  In  the  Anterior  wall  are  the — 

Eustachian  tube, 

Fissura  Glaseri, 

Opening  for  the  laxator  tympani, 

Apertura  chordae  (exit). 

The  tympanum  is  lined  by  a  vascular  mucous  membrane,  which 
invests  the  ossicula  and  chorda  tympani,  and  forms  the  internal 
layer  of  the  memhrani  tympani.  From  tlie  tympanum  it  is  reflected 
into  the  mastoid  cells,  which  it  lines  throughout,  and  passes  through 
the  Eustachian  tube  to  become  continuous  with  the  mucous  mem- 
brane of  the  pharynx. 

Vessels  and  A'erues. — The  Arteries  of  the  tympanum  are  derived 
from  the  internal  maxillary,  internal  carotid,  and  posterior  auricular. 


INTERNAL  EAR.  485 

Its  JVerves  are — 1.  Minute  branches  from  the  facial,  which  are 
distributed  to  the  stapedius  muscle.  2.  The  chorda  tympani,  which 
leaves  the  facial  nerve  near  to  the  stylo-mastoid  foramen,  and  arches 
upwards  to  enter  the  tympanum  at  the  root  of  the  pyramid  ;  it  then 
passes  forwards  between  the  handle  of  the  malleus  and  long  process 
of  the  incus,  to  its  proper  opening  in  the  fissura  Glaseri.  3.  The 
tympanic  branches  of  J  a  cob  son's  nerve,  which  are  distributed  to  the 
membranes  of  the  i'enestra  ovalis  and  fenestra  rotunda,  and  to  the 
Eustachian  tube,  and  form  a  plexus  by  communicating  with  the 
carotid  plexus  and  otic  ganglion.  4.  A  filament  from  the  otic  gan- 
glion to  the  tensor  tympani  muscle. 

INTERNAL    EAR. 

The  Internal  ear  is  called  labyrinth,  from  the  complexity  of  its 
communications  :  it  consists  of  a  membranous  and  an  osseous  por- 
tion. The  osseous  labyrinth  presents  a  series  of  cavities  which  are 
channeled  through  the  substance  of  the  petrous  bone,  and  is  situated 
between  the  cavity  of  the  tympanum  and  the  meatus  audilorius  in- 
ternus.     It  is  divisible  into  the — 

^'  Vestibule, 

Semicircular  canals, 
Cochlea. 

The  Vestibule  is  a  small  three-cornered  cavity,  compressed  from 
without  inwards,  and  situated  immediately  within  the  inner  wall  of 
the  tympanum.  The  three  corners  which  are  named  ventricles  or 
cornua  are  placed,  one  anteriorly,  one  superiorly,  and  one  poste- 
riorly. 

The  anterior  ventricle  receives  the  oval  aperture  of  the  scala 
vestibuli;  the  superior,  the  ampullary  openings  of  the  superior  and 
horizontal  semicircular  canals;  the  posterior  ventricle  receives  the 
ampullary  opening  of  the  oblique  semicircular  canal,  the  common 
aperture  of  the  oblique  and  perpendicular  canals,  the  termination  of 
the  horizontal  canal,  and  the  aperture  of  the  aquaeductus  vestibuli. 
In  the  anterior  ventricle  is  a  small  depression,  which  corresponds 
"with  the  posterior  segment  of  the  cul  de  sac  of  the  meatus  audi- 
torius  internus ;  it  is  called  the  fovea  hemispherica,  and  is  pierced 
by  a  cluster  of  small  openings,  the  macula  cribrosa.  In  the  superior 
ventricle  of  the  vestibule  is  another  small  depression,  the  fovea 
elliptica,  which  is  separated  from  the  fovea  hemispherica  by  a  pro- 
jecting crest,  the  eminentia  pyramidalis.  The  latter  is  pierced  by 
numerous  minute  openings  for  the  passage  of  nervous  filaments. 
The  posterior  ventricle  presents  a  third  small  depression,  the  fovea 
sulciformis,  which  leads  upwards  to  the  ostium  aquaeductus  vestibuli. 
The  internal  wall  of  the  vestibule  corresponds  with  the  bottom  of 
the  cul  de  sac  of  the  meatus  auditorius  internus',  and  is  pierced  by 
numerous  small  openings  for  the  transmission  of  nervous  filaments. 
In  the  external  or  tympanic  wall  is  the  reniform  opening  of  the 

41* 


486  OPENINGS  OF  THE  VESTIBULE. 

fenestra  ovalis  (fenestra  vestibuli),  the  margin  of  which  presents  a 
projecting  rim  towards  the  cavity  of  the  vestibule. 

The  openings  of  the  vestibule  may  be  arranged,  like  those  of  the 
tympanum,  into  large  and  small. 

The  Large  openings  are  seven  in  number,  viz.  the — 

Fenestra  ovalis, 

Scala  vestibuli, 

Five  openings  of  the  three  semicircular  canals. 

The  Small  openings  are  the — 

Aqugeductus  vestibuli, 

Openings  for  small  arteries. 

Openings  for  branches  of  the  auditory  nerve. 

The  Fenestra  ovalis  has  already  been  described ;  it  is  the  opening 
into  the  tympanum. 

The  opening  of  the  scala  vestibuli  is  the  oval  termination  of  the 
vestibular  canal  of  the  cochlea. 

The  Aqucsductus  vestibuli  (canal  of  Colunnius)  is  the  commence- 
ment of  the  small  canal  which  opens  under  the  osseous  scale  upon 
the  posterior  surface  of  the  petrous  bone.  It  gives  a  passage  to  a 
process  of  membrane  which  is  continuous  internally  with  the  lining 
membrane  of  the  vestibule,  and  externally  with  the  dura  mater,  and 
to  a  small  vein. 

The  Openings  for  the  arteries  and  nerves  are  situated  in  the  in- 
ternal wall  of  the  vestibule,  and  correspond  with  the  termination  of 
the  meatus  auditorius  internus. 

The  Semicircular  Canals  are  three  bony  passages  which  com- 
municate with  the  vestibule,  into  which  they  open  by  both  extre- 
mities. Near  one  extremity  of  each  of  the  canals  is  a  remarkable 
dilatation  of  its  cavity,  which  is  called  the  ampulla  (sinus  ampul- 
laceus).  The  superior  or  perpendicular  canal  (canalis  semicircu- 
laris  verticalis  superior),  is  directed  transversely  across  the  petrous 
portion  of  the  temporal  bone,  forming  a  projection  upon  the  anterior 
face  of  the  petrous  bone.  It  commences  by  means  of  an  ampulla 
in  the  superior  ventricle  of  the  vestibule,  and  terminates  posteriorly 
by  joining  with  the  oblique,  and  forming  a  common  canal,  which 
opens  into  the  upper  part  of  the  posterior  ventricle.  The  middle  or 
oblique  canal  (canalis  seminircularis  verticalis  posterior),  corresponds 
with  the  posterior  part  of  the  petrous  portion  of  the  temporal  bone ; 
it  commences  by  an  ampullary  dilatation  in  the  posterior  ventricle, 
and  curves  nearly  perpendicularly  upwards  to  terminate  in  the 
common  canal.  In  the  ampulla  of  this  canal  are  numerous  minute 
openings  for  nervous  fllamenis.  The  inferior  or  horizontal  canal 
(canalis  scmicircularis  liorizontalis),  is  directed  outwards  towards 
the  [)ase  of  the  petrous  bone,  and  is  shorter  than  the  two  preceding. 
It  commences  by  an  ampullary  dilatation  in  the  superior  ventricle, 
and  terminates  in  the  posterior  ventriclo. 


COCHLEA — MODIOLUS. 


487 


170. 


The  Cochlea  (snail  shell)  forms  the  anterior  portion  of  the  laby- 
rinth, corresponding  by  its  apex  with 
the  anterior  wall  oi'the  petrous  bone, 
and  by  its  base  with  the  anterior 
depression  at  the  bottom  of  the  cul 
de  sac  of  the  meatus  auditorius  in- 
tern us.  It  consists  of  an  osseous 
and  gradually  tapering  canal,  about 
one  inch  and  a  half  in  length,  which 
makes  two  turns  and  a  half  spirally 
around  a  central  axis  called  the 
modiolus. 

The  central  axis  or  modiolus  is 
large  near  its  base  where  it  corre- 
sponds with  the  first  turn  of  the  cochlea,  and  diminishes  in  diameter 
towards  its  extremity.  At  its  base  it  is  pierced  by  numerous 
minute  openings  which  transmit  the  filamentsof  the  cochlear  nerve. 
These  openings  are  disposed  in  a  spiral  manner,  hence  they  have 
received  from  Colunnius*  the  name  of  tractus  spiralis  foraminu- 
lentus.  The  modiolus  is  every  where  traversed  in  the  direction 
of  its  length  by  minute  canals,  which  proceed  from  the  tractus 
spiralis  foraminulenius,  and  terminate  upon  the  sides  of  the  modiolus, 
by  opening  into  the  canal  of  the  cochlea  or  upon  the  surface  of  its 
lamina  spiralis.  The  central  canal  of  the  tractus  spiralis  foraminu- 
lentus  is  larger  than  the  rest,  and  is  named  the  tubulus  centralis 
modioli;  it  is  continued  onwards  to  the  extremity  of  the  modiolus, 
and  transmits  a  nerve  and  a  small  artery,  the  arteria  centralis 
modioli. 

The  interior  of  the  canal  of  the  cochlea  is  partially  divided  into 
two  passages  (scales)  by  means  of  a  thin  and  porous  lamina  of  bone 
(zonula  ossea  laminae  spiralis),  which  is  wound  spirally  aroimd  the 
modiolus  in  the  direction  of  the  canal.  This  bony  septum  extends 
for  about  two-thirds  across  the  diameter  of  the  canal,  and  in  the 
fresh  subject  is  prolonged  to  the  opposite  wall  by  means  of  a  mem- 
branous layer,  so  as  to  constitute  a  complete  partition — the  lamina 


Fig.  ]  70.  The  cochlea  divided  parallel  with  its  axis,  throug'h  the  centre  of  the  modio- 
lus. After  Breschet.  1.  The  modiolus.  2.  The  infundihulum  in  which  the  modiolus 
terminates.  3,  .3.  The  cochlear  nerve,  sending  its  filaments  through  the  centre  of  the 
modiolus.  4,  4.  The  scala  tympani  of  the  first  turn  of  the  cochlea.  5,  5.  The  scala 
vestibuli  of  the  first  turn.  6.  Section  of  the  lamina  spiralis,  its  zonula  ossea  ;  one  of 
the  filaments  of  the  cochlear  nerve  is  seen  passing  between  the  two  layers  of  the  lamina 
spiralis  to  be  distributed  upon  the  membrane  which  invests  the  lamina.  7.  The  mem- 
branous  portion  of  the  lamina  spiralis.  8.  Loops  formed  by  the  filaments  of  the 
cochlear  nerve.  9,  9.  Scala  tympani  of  the  second  turn  of  the  cochlea.  10,  10.  Scala 
vestibuli  of  the  second  turn;  the  septum  between  the  two  is  the  lamina  -spiralis.  11. 
The  scala  tympani  of  the  remaining  half  turn.  12.  The  remaining  half  turn  of  the 
scala  vestibuli ;  the  dome  placed  over  this  half  turn  is  the  cupola.  13.  The  lamina  of 
bone  which  forms  the  floor  of  the  scala  vestibuli  curving  spirally  round  to  constitute 
the  infundibnlum  (2).  14.  The  helicotrcma  through  which  a  bristle  is  passed;  its 
lower  extremity  issues  from  the  scala  tympani  of  the  middle  turn  of  the  cochlea. 

*  Dominico  Cotunnius,  an  Italian  pliysicinn ;  his  dissertation  "  De  Aquceductibus 
Auris  Humanae  Intern£s,"  was  published  in  Naples  in  1761. 


483  .     MEMBRANOUS  LABYRINTH. 

spiralis.  The  osseous  lamina  spiralis  consists  of  two  thin  lamellae 
of  bone,  between  which,  and  through  the  perforations  on  their  sur- 
faces, the  filaments  of  the  cochlear  nerve  reach  the  membrane  of 
the  cochlea.  At  the  apex  of  the  cochlea  the  lamina  spiralis  termi- 
nates in  a  pointed,  hook-shaped  process,  the  hamulus  laminas  spiralis. 
The  two  scalae  of  ihe  cochlea  which  are  completely  separated 
throughout  their  length  in  the  living  ear,  communicate  superiorly 
over  the  hamulus  laminae  spiralis  by  means  of  an  opening  common 
to  both,  which  has  been  termed  by  Breschet  helico-trema  (£Xi|,  sXiVcw 
volvere — r^riixa).  Inferiorly,  one  of  the  two  scalae,  the  scala  vestibuli, 
terminates  by  means  of  an  oval  aperture  in  the  anterior  ventricle 
of  the  vestibule;  while  the  other,  the  scala  tympani,  becomes  some- 
what expanded,  and  opens  into  the  tympanum  through  the  fenestra 
rotunda  (fenestra  cochleae).  Near  to  the  termination  of  the  scala 
tympani  is  the  small  opening  of  the  aquasductus  cochleae. 

The  internal  surface  of  the  osseous  labyrinth  is  lined  by  afibro- 
serous  membrane,  which  is  analogous  to  the  dura  mater  in  perform- 
ing the  office  of  a  periosteum  by  its  exterior,  whilst  it  fulfils  the 
purpose  of  a  serous  membrane  by  its  internal  layer,  secreting  a 
limpid  fluid,  the  aqua  labyrinthi  (hquor  Cotunnii),  and  sending  a 
reflection  inwards  upon  the  nerves  distributed  to  the  membranous 
labyrinth.  In  the  cochlea  the  membrane  of  the  labyrinth  invests 
the  two  surfaces  of  the  bony  lamina  spiralis,  and  being  continued 
from  its  border  across  the  diameter  of  the  canal  to  its  outer  wall, 
forms  the  membranous  lamina  spiralis  and  completes  the  separation 
betw^ecn  the  scala  tympani  and  scala  vestibuli.  The  fenestra  ovalis 
and  fenestra  rotunda  are  closed  by  an  extension  of  this  membrane 
across  them,  assisted  by  the  membrane  of  the  tympanum  and  a 
proper  intermediate  layer.  Besides  lining  the  interior  of  the  osseous 
cavity  the  membrane  of  the  labyrinth  sends  two  delicate  processes 
along  the  aqueducts  of  the  vestibule  and  cochlea  to  the  internal  sur- 
face of  the  dura  mater  of  the  petrous  portion  of  the  temporal  bone, 
with  which  they  are  continuous.  These  processes  are  the  remains  of 
a  communication  originally  subsisting  between  the  dura  mater  and 
the  cavity  of  the  labyrinth.* 

The  Membranous  Labyrtnth  is  smaller  in  size,  but  a  perfect 
counterpart  with  respect  to  form,  of  the  vestibule  and  semicircular 
canals.  It  consists  of  a  small  elongated  sac,  saccuhis  communis 
(utriculus  communis) ;  of  three  semicircular  membranous  canals, 
which  correspond  with  the  osseous  canals,  and  communicate  with 
the  sacculus  communis;  and  of  a  small  round  sac  (sacculus  pro- 
prius);  which  occupies  the  anterior  ventricle  of  the  vestibule,  and 

*  Cotunnius  rojrardcd  tlicsc  ])rocesscs  as  tubular  can;ils,  through  which  the  supera- 
bundant atjua  labyrinthi  might  be  expelled  into  the  cavity  of  th'i  cranium.  Mr.  Whar- 
ton Jones,  in  tiie  articlt!  "Organ  of  Hearing"  in  the  Cycloi)n;dia  of  Anntomy  and 
Ptiysinlogy,  also  describes  them  aa  tubular  canals  vviiich  (erminatc  beneiith  tlie  dura 
niatcr  of  the  pritrou.s  bone  in  a  small  dilated  pouch.  In  the  c.ir  of  a  man  deaf  and 
dumb  from  birth,  he  found  tiic  termination  of  the  aqueduct  of  the  vcslibulc  of  unusu- 
ally large  size  in  consequence  of  irregular  developenicnt. 


MEMBRANOUS  LABYRINTH. 


489 


Fig.  171. 


lies   in   close    contact  with   the  external   surface   of  the   sacculus 
communis. 

The  membranous  semicircular  canals 
are  two-thirds  smaller  in  diameter  than 
the  osseous  canals.  The  membranous 
labyrinth  is  retained  in  its  position  by 
means  of  the  numerous  nervous  filaments 
which  are  distributed  to  it  from  the  open- 
ings in  the  inner  wall  of  the  vestibule,  and 
is  separated  from  the  lining  membrane  of 
the  labyrinth  by  the  aqua  labyrinth!. 

The  structure  of  the  membranous  la- 
byrinth is  composed  of  four  layers:  an 
externa!  or  serous  layer,  derived  from 
the  lining  membrane  of  the  labyrinth  ;  a 
vascular  layer,  in  which  an  abundance  of 
minute  vessels  are  distributed  ;  a  nervous 
layer  formed  by  the  expansion  of  the  fila- 
ments of  the  vestibular  nerve,  and  of  an  in- 
ternal and  serous  membrane,  by  which  the  limpid  fluid  which  fills 
the  membranous  labyrinth  is  secreted.  Some  small  patches  of  pig- 
ment have  been  observed  by  Mr.  Wharton  Jones  in  the  tissue  of 
the  membranous  labyrinth  of  man.  Among  animals  such  spots  are 
constant.  . 

Fig.  171.  The  labyrinth  of  the  left  ear,  laid  open  in  order  to  show  its  cavities  and 
the  membranous  labyrinth.  After  Breschet.  1.  The  cavity  of  the  vestibule,  opened 
from  its  anterior  aspect  in  order  to  show  the  three-cornered  form  of  its  interior,  and  the 
membranous  labyrinth  which  it  contains.  The  figure  rests  upon  the  common  saccule 
of  the  membranous  labyrinth, — the  sacculus  communis.  2.  The  ampulla  of  the  supe- 
rior or  perpendicular  semicircular  canal,  receiving  a  nervous  fasciculus  from  the  supe- 
rior branch  of  the  vestibular  nerve.  3,  4.  The  superior  or  perpendicular  canal  with 
its  contained  membranous  canal.  5.  The  ampulla  of  the  inferior  or  horizontal  semi- 
circular  canal,  receiving  a  nervous  fasciculus  from  the  superior  branch  of  the  vesti- 
bular nerve.  6.  The  termination  of  the  membranous  canal  of  the  horizontal  semicir- 
cular canal  in  the  sacculus  communis.  7.  The  ampulla  of  the  middle  or  oblique  semi- 
circular canal,  receiving  a  nervous  fasciculus  from  the  inferior  branch  of  the  vestibular 
nerve.  8.  The  oblique  semicircular  canal  with  its  membranous  canal.  9.  The  com- 
mon canal,  resulting  from  the  union  of  the  perpendicular  with  the  oblique  semicircular 
canal.  10.  The  membranous  common  canal  terminating  in  the  sacculus  communis. 
11.  The  otoconite  of  the  sacculus  communis  seen  through  the  membranous  parietes  of 
that  sac.  A  nervous  fasciculus  from  the  inferior  branch  of  the  vestibular  nerve  is  seen 
to  be  distributed  to  the  sacculus  communis  near  to  the  otoconite.  The  extremity  of 
the  sacculus  above  the  otoconite  is  lodged  in  the  superior  ventricle  of  the  vesti- 
bale,  and  that  below  in  the  inferior  ventricle.  12.  The  sacculus  proprius  situated  in 
the  anterior  ventricle  ;  its  otoconite  is  scon  through  its  membranous  parietes,  and  a 
nervous  fasciculus  derived  from  the  middle  branch  of  the  vestibular  nerve  is  distributed 
to  it.  The  spaces  around  the  membranous  labyrinth  are  occupied  by  the  aqua  labyrinthi. 
13.  The  first  turn  of  the  cochlea;  the  figure  is  situated  in  the  scala  tympani.  14. 
The  extremity  of  the  scala  tympani  corresponding  with  the  fenestra  rotunda.  15. 
The  lamina  spiralis;  the  figure  is  situated  in  the  scala  vestibuli.  16.  The  opening  of 
the  scala  vestibuh  into  the  vestibule.  17.  The  second  turn  of  the  cochlea;  the  figure 
is  placed  upon  the  lamina  spiralis,  and  therefore  in  the  scala  vestibuli,  the  scala  tym- 
pani being  beneath  the  lamina.  18.  The  remaining  half  turn  of  the  cochlea  ;  the 
figure  is  placed  in  the  scala  tympani.  19.  The  lamina  spiralis  terminating  in  a  falci- 
form extremity.  The  dark  space  included  within  the  falciform  curve  of  the  extremity 
of  the  lamina  spiralis  is  the  helicotrema.     20.  The  infundibulum. 


490  DISTRIBUTION  OF  THE  AUDITORY  NERVE. 

The  membranous  labyrinth  is  filled  in  the  interior  with  a  limpid 
fluid,  first  well  described  by  Scarpa,  and  thence  named  liquor 
ScarpEq*  (endolymph,  vitreous  humour  of  the  ear,)  and  contains 
two  small  cal(;areous  masses  called  otoconites.  The  otoconites 
(ouff,  u-Qg  xc'vig,  the  ear-dust),  consist  of  an  assemblage  of  n)inute, 
crystalline  particles  of  carbonate  and  phosphate  of  lime,  held  toge- 
ther by  animal  substance,  and  probably  retained  in  form  by  a  reflec- 
tion of  the  lining  membrane  of  the  membranous  labyrinth.  They 
are  found  suspended  in  the  liquor  Scarpie,  one  in  the  sacculus  com- 
munis, and  the  other  in  the  sacculus  proprius,  from  that  part  of 
each  sac  wath  which  the  nerves  are  connected. 

The  Auditory  Nerve  divides  into  two  branches  at  the  bottom  of 
the  cul  de  sac  of  the  meatus  auditorius  internus;  a  vestibular  nerve, 
and  a  cochlear  nerve.  The  vestibular  nerve,  the  most  posterior  of 
the  two,  divides  into  three  branches,  superior,  middle,  and  inferior. 
The  superior  vestibular  branch  gives  off  a  number  of  filaments 
which  pass  through  the  miinute  openings  of  the  eminentia  pyrami- 
dalis,  and  of  the  superior  ventricle  of  the  vestibule,  and  are  distri- 
buted to  the  sacculus  communis,  and  to  the  ampullas  of  the  perpen- 
dicular and  horizontal  semicircular  canals.  The  middle  vestibular 
branch  sends  off"  numerous  filaments  which  pass  through  the  open- 
ings of  the  macula  cribrosa  in  the  anterior  ventricle  of  the  vestibule, 
and  are  distributed  to  the  sacculus  proprius.  The  inferior  and 
smallest  branch  takes  its  course  backwards  to  the  posterior  wall  of 
the  vestibule,  and  gives  off  filaments  which  pierce  the  wall  of  the 
ampullary  dilatation  of  the  oblique  canal  to  be  distributed  upon  its 
ampulla.  According  to  Stiefensand  there  is  in  the  situation  of  the 
point  of  entrance  of  the  nervous  filaments  into  the  ampullae  a  deep 
depression  upon  the  exterior  of  the  membrane,  and  upon  the  inte- 
rior a  corresponding  projection,  which  forms  a  kind  of  transverse 
septum,  partially  dividing  the  cavity  of  the  ampulla  into  two 
chambers. 

Upon  entering  the  structure  of  the  sacculi  and  ampullae,  the  ner- 
vous filaments  radiate  in  all  directions,  anastomosing  with  each 
other,  and  forming  interlacements  and  loops,  and  they  terminate 
upon  the  inner  surface  of  the  membrane  in  minute  papillae,  resem- 
bling those  of  the  retina. 

The  Cochlear  nerve  divides  into  numerous  filaments  which  enter 
the  foramina  of  the  tractus  spiralis  foraminulentus  in  the  base  of 
the  cochlea,  and  passing  upwards  in  the  canals  of  the  modiolus 
bend  outwards  at  right  angles,  to  be  distributed  in  the  tissue  of  the 
lamina  spiralis.  The  central  portion  of  the  nerve  passes  through 
the  tubulus  centralis  of  the  modiolus,  and  supplies  the  apicial  por- 
tion of  the  lamina  spiralis.  In  the  lamina  spiralis  the  nervous  fila- 
ments lying  side  by  side  on  a  smooth  plane  form  numerous  anasto- 

*  Antonio  Scarpa  is  celcbratcfl  for  several  beautiful  surjric;il  and  anatomical  mono- 
graphs; as,  for  example,  IiIh  worlt  on  "  Aneurism,"  "  Do  Audita  ot  Olfiictu,"  &c.  An 
account  of  the  aqua  l,il>yrinlhi  will  bo  found  in  his  anatomical  observations  "  Dc  Struc- 
tura,  Fencstrae  RotundoB,  et  de  Tympano  Secundario." 


OKGAN  OF  TASTE.  491 

mosing  loops,  and  spread  out  ultimately  into  a  nervous  membrane. 
According  to  Treviianus  and  Gottsche  the  ultimate  terminations  of 
the  filaments  assume  the  form  of  papillne. 

The  Jrteries  of  the  labyrinth  are  derived  principally  from  the 
auditory  branch  of  the  superior  cerebellar  artery. 

ORGAN    OF   TASTE. 

The  Tongue  is  composed  of  muscular  fibres,  which  are  distri- 
buted in  layers  arranged  in  various  directions:  thus,  some  are  dis- 
posed longitudinally;  others  transversely;  others,  again,  obliquely 
and  vertically.  Between  the  muscular  fibres  is  a  considerable  quan- 
tity of  adipose  substance. 

The  tongue  is  connected  posteriorly  with  the  os  hyoides  by  mus- 
cular attachment,  and  to  the  epiglottis  by  mucous  membrane,  form- 
ing the  three  folds  which  are  called  frcena  epiglottidis.  On  either 
side  it  is  held  in  connexion  with  the  lower  jaw  by  mucous  mem- 
brane, and  in  front  a  fold  of  that  membrane  is  formed  beneath  its 
under  surface,  which  is  named  froinum  Ungues. 

The  surface  of  the  tongue  is  covered  by  a  dense  layer  analogous 
to  the  corium  of  the  skin,  which  gives  support  to  the  papillae. 
A  raphe  marks  the  middle  line  of  the  organ,  and  divides  it  into 
symmetrical  halves. 

The  PapillcB  of  the  tongue  are  the — 

Papillae  circumvallatae, 
Papillae  conicas, 
Papillae  filiformes, 
Papillae  fungiformes. 

The  PapillcE  circumvallatcB  are  of  large  size,  and  from  fifteen  to 
twenty  in  number.*  They  are  situated  on  the  dorsum  of  the  tongue, 
near  to  its  root,  and  form  a  row  upon  each  side,  which  meets  its 
fellow  at  the  middle  line,  like  the  two  branches  of  the  letter  V. 
Each  papillae  resembles  a  cone,  attached  by  its  apex  to  the  bottom 
of  a  cup-shaped  depression:  hence  they  are  also  named  papilla 
calyciformes.  This  cup-shaped  cavity  forms  a  kind  of  fossa  around 
the  papilla,  whence  their  name  circumvallatcB. 

At  the  meeting  of  the  tvi'o  rows  of  these  papillae  upon  the  middle 
of  the  root  of  the  tongue,  is  a  deep  mucous  follicle  called  foramen 
ccEcum. 

The  Pa-pilloi  conicce  awd  filiformes  cover  the  whole  surface  of  the 
tongue  in  front  of  the  circumvallatce,  but  are  most  abundant  near  its 
apex.  They  are  conical  and  filiform  in  shape,  and  have  their  points 
diiected  backwards. 

The  PapillcB  fungiformes  are  irregularly  dispersed  over  the  dorsum 
of  the  tongue,  and  are  easily  recognised  amongst  the  other  papillae 
by  their  rounded  heads  and  larger  size.  A  number  of  these  papillae 
will  generally  be  observed  at  the  tip  of  the  tongue. 

*  I  thinli  it  rare  to  see  more  than  nine,  four  on  each  side  of  the  middle  one,  which 
is  always  the  largest. — G. 


492  ORGAN  OF  TOUCH. 

Behind  the  papillae  circumvallatre,  at  the  root  of  the  tongue,  are  a 
number  oi  mucous  glands,  which  open  upon  the  surface.  They  have 
been  improperly  described  as  papillae  by  some  auihors. 

Vessels  and  Nerves. — The  tongue  is  abundantly  supplied  with 
blood  by  the  lingual  arteries. 

The  JVerves  are  three  in  number,  and  of  large  size: — 1.  The 
gustatory  branch  of  the  fifth,  which  is  distributed  to  the  papillae,  and 
is  the  nerve  of  common  sensation  and  of  taste.  2.  The  sIosso--plm- 
ryngeal,  which  is  distributed  to  the  mucous  membrane,  follicles,  and 
glands  of  the  tongue,  is  a  nerve  of  sensation  and  motion  ;  it  also 
serves  to  associate  the  tongue  with  the  pharynx  and  larynx.  Pa- 
nizza's  experiments,  tending  to  prove  that  this  is  the  true  nerve  of 
taste,  are  rendered  questionable  by  recent  experiments.  3.  The 
lingual,  which  is  the  motor  nerve  of  the  tongue,  and  is  distributed 
to  the  muscles. 

The  Mucous  membrane  which  invests  the  tongue,  is  continuous  with 
the  cutis  along  the  margins  of  the  lips.  On  cither  side  of  the  fraenum 
linguae  it  may  be  traced  through  the  sublingual  ducts  into  the  sub- 
lingual glands,  and  along  Wharton's*  ducts  into  the  sub-maxillary 
glands;  from  the  sides  of  the  cheeks  it  passes  through  the  openings 
of  Stenon'sf  ducts  to  the  parotid  gland ;  in  the  fauces,  it  forms  the 
assemblage  of  follicles  called  tonsils,  and  may  be  thence  traced 
downwards  into  the  larynx  and  pharynx,  where  it  is  continuous 
with  the  general  gastro-pulmonary  mucous  membrane. 

Beneath  the  mucous  membrane  of  the  mouth  are  a  number  of 
small  glandular  granules,  which  pour  forth  their  secretion  upon  the 
surface.  A  considerable  number  of  them  are  situated  within  the 
lips,  in  the  palate,  and  in  the  floor  of  the  mouth.  They  are  named 
from  the  position  which  they  may  chance  to  occupy,  labial,  pala- 
tine glands,  &C.J 

ORGAN    OF    TOUCH. 

The  Skin  is  composed  of  three  layers,  viz.  the 

Cutis, 

Rete  mucosum, 

Cuticle. 

The  Cutis  (dermis),  or  true  skin,  covers  the  entire  surface  of  the 
body,  and  is  continuous  with  the  mucous  membrane  which  lines  its 
cavities.  It  consists  of  two  layers,  a  deep  one  called  corium,  and  a 
superficial  or  papillary  layer. 

The  Corium  is  the  base  of  support  to  the  skin,  and  owes  its  den- 
sity of  structure  to  an  interlacement  of  fibrous  bands  which  form  a 

*  Thomas  Wharton,  an  English  physician,  devoted  considerable  attention  to  the  ana- 
tomy  of  the  various  glands :  his  work,  entitled  "  Adenographia,"  &,c.,  was  published 
in  H).56. 

+  Nicliolas  Stcnon,  a  Danish  anatomist :  he  was  made  professor  in  Copenhagen  in 
1672. 

t  These  glands  are  salivary,  having  the  same  stracturc  as  the  parotid  and  secreting 
the  same  fluid. — G. 


ORGAN  OF  TOUCH. 


493 


Fig.  172. 


m: 


firm  and  elastic  web.  By  its  under  surface  it  is  connected  with  the 
common  superficial  fascia  of  the  body,  and  presents  a  number  of 
areolaj,  in  which  are  lodged  small  masses  of  adipose  tissue. 

On  the  upper  surface  the  fibres  are  more  closely  aggregated,  and 
form  a  smooth  plane  for  the  support  of  the  papillary  layer. 

The  corium  differs  very  much 
in  thickness  in  diflerent  parts  of 
the  body  ;  thus,  on  the  lips,  eye- 
lids, and  scrotum  it  is  extremely 
thin.  On  the  head,  back,  soles  of 
the  feet,  and  palms  of  the  hand  it 
is  very  thick ;  and  on  the  more 
exposed  parts  of  the  body  it  is 
much  thicker  than  on  those  which 
are  protected. 

The  Pd'pillary  layer  is  soft,  and 
formed  by  minute  papillse  v\hich 
cover  every  part  of  its  surface.  '^^ 
On  the  body  generally,  the  papillse  ^ 
are  very  small  and  irregular  in 
their  distribution ;  they  are  best 
seen  in  the  palm  of  the  hand  or 
sole  of  the  foot,  where  they  are 
disposed  in  linear  ridges,  as  indi- 
cated by  the  markings  on  the 
cuticle.  The  ridges  of  papillse  in 
these  situations  are  separated  from  each  other  by  longitudinal  fur- 
rows, and  are  divided  by  transverse  furrows  into  small  quadrilateral 
rounded  masses.  These  quadrilateral  masses  are  each  composed 
of  a  considerable  number  of  minute  papillae,  which  are  conical  in 
form  and  variable  in  length,  one  or  two  of  the  papillse  in  each  mass 
beins  ffenerallv  longer  than  the  rest.  In  the  middle  of  the  trans- 
verse  furrow,  between  the  papillse,  is  the  openmg  for  the  perspira- 
tory duct. 

The  papillae  beneath  the  nail  have  a  peculiar  form  and  arrange- 
ment. At  the  root  of  the  nail  they  are  numerous,  but  small  and 
very  vascular;  opposite  to  the  part  of  the  nail  called  lunula,  they 
are  scarcely  raised  above  the  surface,  and  less  vascular;  but  beyond 
this  point  the}'  form  lengthened  vascular  plicae,  which  afford  a  large 
surface  of  secretion.     These  lengthened  papillse  deposit  the  horny 


Fig.  172.  The  anatomy  of  the  skin.  1.  The  cuticle,  showing  the  oblique  larninaj  of 
which  it  is  composed  and  the  imbricated  disposition  of  the  ridges  upon  its  surface.  2. 
The  rete  mucosum.  3.  Two  of  the  quadrilateral  papillary  masses,  such  as  are  seen  in 
the  palm  of  the  hand  or  sole  of  the  foot ;  they  are  composed  of  minute  conical  papillce. 
4.  The  deeper  layer  of  the  cutis,  tlie  corium.  5.  Adipose  vesicles;  showing  tinir  ap- 
pearance beneath  the  microsaope.  6.  A  perspiratory  gland  with  its  spiral  duct,  such 
as  is  seen  in  the  palm  of  the  liand  or  sole  of  the  foot.  7.  Anotlier  perspiratory  gland 
with  a  straighter  duct,  suci)  as  is  seen  in  the  scalp.  8.  Two  hairs  from  the  scalp,  en- 
closed in  their  follicles;  their  relative  depth  in  the  skin  is  preserved.  9.  A  pair  of  se- 
baceous glands,  opening  by  short  ducts  into  the  follicle  of  tlie  hair. 

42 


494  EETE  MUCOSUM. 

secretion  in  longitudinal  lainellas,  which  give  to  the  nail  the  ribbed 
apj'caiance  which  it  presents  upon  its  surface. 

Vessels  and  Amerces. — The  papillre  are  abundantly  supplied  with 
vessels  and  nerves;  the  former  to  enable  them  to  perform  the  office 
of  secretion  in  the  production  of  the  cuticle,  the  latter  to  give  them 
the  sensibiHty  necessary  to  an  organ  of  touch. 

The  Rete  mucnsum  is  the  soft  medium  which  is  situated  between 
the  papillary  surface  of  the  cutis  and  cuticle ;  after  a  careful  macera- 
tion it  may  be  separated  as  a  distinct  layer, 
Fig.  173.  particularly  in  the  negro,  where  it  is  firmer 

than  in  the  European,  and  contains  the  colour- 
ing matter  of  the  skin. 

The  name  rete  mucosum,  given  to  it  by 
Malpighi,  conveys  a  very  inaccurate  notion 
of  its  structure;  for  it  is  neither  a  network, 
nor  is  it  mucous.  It  is  thin  upon  the  general 
surface  of  the  body  ;  but  is  thicker  in  the  palm 
of  the  hand  and  sole  of  tlie  foot,  and  presents 
a  close  correspondence  with  the  thickness  of 
the  cuticle.  Examined  with  the  microscope, 
it  is  seen  to  be  moulded  accurately  upon  the 
papillae,  being  thick  in  the  spaces  between 
these,  and  thin  over  their  convexities  ;  hence  arises  the  appearance 
of  a  network.  In  the  rete  mucosum  from  the  hand,  these  depressions 
are  arranged  in  a  linear  series,  as  are  the  papillae;  in  other  situa- 
tions they  are  more  irregular,  but  correspond  always  with  the  dis- 
tribution of  the  papillffi. 

The  rete  mucosum  is  the  freshly  secreted  layer  of  cuticle,  and 
gradually  hardens  as  it  approaches  the  surface.  It  has  been  shown 
by  Henle  to  be  composed  of  minute  oval  vesicular  cells,  which  be- 
come converted  in  the  hardened  cuticle  into  flattened  scales,  each 
containing  a  central  nucleus.  The  dark  pigment  of  the  negro  exists 
in  the  form  of  small  granules  of  colouring  matter. 

The  cuticle  (epidermis,  scarf-skin)  is  the  horny  unorganized 
lamella  which  covers  and  protects  the  entire  surface  of  the  more 
delicate  layers  of  the  skin.     In  situations  exposed  to  pressure,  as 

Fijr.  173.  Anatomy  of  a  portion  of  skin  talten  from  tlie  palm  of  the  tiand.  1,  1.  The 
papillary  layer,  in  which  the  longitudinal  furrows  (2)  marl^ing'  the  arrangements  of 
the  p.ipiilcu  into  ridges  is  shown.  Each  ridge  is  moreover  divided  by  transverse  furrows 
(.3)  into  Buiall  riuadrangular  masses.  Tlie  quadrangular  masses  consist  of  a  tuft  of 
minute  conical  papilhc,  of  whicli  one  or  two  are  frequently  longer  and  larger  tiian  the 
rest.  In  this  figure  the  long  papillfE  are  alone  seen,  the  rest  being  too  numerous  to 
introduce  into  a  wood-engraving.  4,  4.  The  rete  mucosum  raised  from  the  papillary 
layer  and  turned  back;  the  under  surface  of  this  stratum  |)rcsenls  an  aecnrale  impres- 
sion of  the  papillary  layer;  on  which  are  seen  longitudinal  ridges  corresponding  with 
the  longitudin  il  furrows,  transverse  ridges  corresponding  witli  the  transversi;  furrows, 
and  quadriingular  depressions  corresponding  with  ihe  quiidrangidar  masses  of  p;i])illce. 
Moreover,  wherever  one  of  the  long  papillae  exists,  a  distinct  coniciil  sheath  will  be 
found  in  the  rete  mucosum.  b,  5.  Perspiratory  ducts  drawn  out  straight  by  the  sepa- 
ration of  the  rete  mucosum  from  the  pupillary  layer;  the  point  at  which  each  perspi- 
rat'.ry  duct  issues  from  thf;  i)a[)illary  layer,  and  pierces  the  rete  mucosum,  is  the  middle 
of  the  transverse  furrow  between  the  quadrangular  masses. 


APPENDAGES  TO  THE  SKIN.  495 

the  palm  of  the  hand  and  sole  of  the  foot,  it  is  very  thick;  on  other 
parts  it  forms  only  a  thin  layer.  The  cuticle  is  marked  on  the  sur- 
face by  a  network  of  hues:  these  are  more  numerous  and  larger 
near  to  joints,  where  they  form  deep  wrinkles  on  account  of  the 
inelastic  nature  of  its  structure.  Their  appearance  differs  in  dif- 
ferent regions  of  the  body  ;  but  every  where  depends  upon  the  same 
cause,  the  inelasticity  of  the  cuticle.  At  the  entrance  to  the  cavi- 
ties of  the  body  it  is  continuous  with  the  epithelium  or  cuticular 
covering  of  the  mucous  membrane. 

The  cuticle,  in  minute  structure,  consists  of  several  successions 
of  laminae  which  are  secreted  by  the  cutis;  the  last  secreted  layer 
being  the  rete  mucosum.  The  rete  mucosum  is  composed  of  small 
round  masses  or  nuclei,  connected  together  by  a  glutinous  fluid 
containing  a  number  of  pigment  granules.  Each  nucleus  contains 
in  its  interior  a  minute  central  point,  the  nucleus-corpuscule,  and 
around  the  exterior  of  the  nucleus  a  vesicle  is  by  degrees  produced. 
The  middle  lamince  of  the  cuticle  are  composed  of  these  nucleated 
vesicles,  which  are  more  and  more  compressed  and  flattened  as  they 
are  observed  nearer  to  the  surface.  In  the  superficial  lamince  the 
vesicles  are  converted  into  thin  scales,  in  the  centre  of  which  the 
nucleus  with  the  nucleus-corpuscule  is  still  apparent.  The  laminae 
of  the  cuticle  are  disposed  on  the  same  plane  with  the  surface  of 
the  skin  in  many  situations,  in  others  they  are  placed  obliquely,  so 
as  to  project  by  their  free  extremities  upon  the  surface;  in  the  palm 
of  the  hand  and  sole  of  the  foot  these  layers  correspond  with  the 
elevations  of  the  papillse,  and  present  an  imbricated  linear  surface. 
This  is  particularly  seen  on  the  points  of  the  fingers  where  the  rows 
of  papillse  have  a  circular  arrangement.  The  superficial  laminae 
of  the  cuticle  are  being  continually  thrown  off  by  exfoliation  or 
removed  by  abrasion,  to  give  place  to  the  deep  and  more  newly 
formed  layers. 

Upon  the  inner  surface  of  the  cuticle  a  number  of  depressions 
and  linear  furrows  are  seen,  corresponding  with  the  projections  of 
the  papillse.  A  number  of  conical  processes  are  also  observed  on 
this  surface,  which  correspond  with  the  passage  of  hairs  through 
the  cuticle,  and  with  the  openings  of  the  perspiratory  ducts. 

The  Openings  in  the  cuticle  are  the  pores  or  openings  for  the  per- 
spiratory ducts,  the  openings  for  the  passage  of  the  hairs,  and  those 
of  the  sebaceous  follicles. 

APPENDAGES    TO    THE    SKI  IV. 

The  appendages  to  the  skin  are  the  nails,  hairs,  sebaceous  glands, 
and  perspiratory  glands  and  ducts. 

The  J\'ails  are  parts  of  the  cuticle  secreted  in  the  same  manner, 
composed  of  the  same  material,  but  disposed  in  a  peculiar  way  to 
serve  an  especial  purpose — the  protection  of  the  tactile  extremities 
of  the  fingers.  They  are  inserted  by  their  root  into  a  deep  groove 
(matrix)  of  the  skin,  and  are  firmly  attached  to  the  papillary  surface 
by  the  close  connexion  of  the  papillae  with  the  longitudinal  laminae. 


496  PORES  OF  THE  SKIN. 

The  white  semilunar  segment  near  the  root  of  the  nail  is  called  the 
lunula.  The  cuticle  is  closely  connected  with  it  all  round,  and  in 
maceration  the  nail  comes  off  with  that  layer. 

The  Hairs  have  a  very  different  structure  and  arrangement  from 
that  of  the  nails:  they  are  inserted  for  a  considerable  depth  within 
the  integument,  and  terminate  in  conical  or  somewhat  bulbous  roots. 
Each  hair  is  enclosed  beneath  the  surface  by  a  vascular  secretory 
follicle,  which  regulates  its  form  during  growth. 

Hairs  are  very  rarely  completely  cylindrical;  they  are  generally 
more  or  less  compressed,  and  somewhat  prismoid  in  form.  The 
transverse  section  is  reniform ;  in  texture  it  is  dense  and  homoge- 
neous towards  the  circumference,  and  porous  and  cellular  in  the 
centre  like  the  pith  of  a  plant. 

The  Sebaceous  glands  are  abundant  in  some  parts  of  the  skin,  as 
in  the  armpits,  the  nose,  &c.,  and  vary  in  complexity  of  structure 
from  a  simple  pouch-like  follicle  to  a  lobulated  gland.  At  the  ex- 
tremity of  the  nose  they  have  several  lobes;  and  in  the  scalp  they 
are  lobulated  like  a  bunch  of  grapes,  and  terminate  in  the  follicles 
of  the  hairs  near  to  the  surface  of  the  skin.  They  secrete  an  oily 
fluid  which  is  poured  out  upon  the  surface  of  the  skin,  and  tends  to 
preserve  the  flexibility  of  the  cuticle. 

The  PersfAratory  ducts  are  minute  spiral  tubes  which  commence 
in  small  lobulated  glands,  situated  deeply  in  the  integument  beneath 
the  corium  and  among  the  adipose  vesicles.  They  are  easily  seen 
by  examining  a  thin  perpendicular  section  of  the  skin  from  the  palm 
of  the  hand,  with  a  lens  of  moderate  power.  Proceeding  from  the 
glands,  the  ducts  ascend  through  the  transverse  furrow,  between 
the  quadrilateral  masses  of  papillse  and  through  the  rete  mucosum 
to  terminate  by  open  pores  upon  the  surface  of  the  cuticle.  That 
portion  of  the  tube  which  is  situated  in  the  cuticle,  is  pretty  equally 
spiral ;  but  that  below  the  level  of  the  papillary  surface  is  very  irre- 
gularly twisted,  and  is  often  nearly  straight.  In  the  scalp  the  tubes 
are  serpentine,  or  but  slightly  curved. 

A  good  view  of  the  perspiratory  ducts  passing  between  the  cutis 
and  cuticle,  may  be  obtained  by  peeling  off  the  cuticle  from  the 
palm  of  the  hand  in  a  decomposing  limb;  or  by  scalding  a  small 
portion  of  integument  and  then  separating  the  cuticle. 

The  Pores  are  best  observed  during  perspiration,  when  the  fluid 
is  seen  oozing  through  their  minute  openings.  In  the  hand  and  sole 
of  the  foot  they  are  easily  seen  by  the  naked  eye  without  this  assis- 
tance. They  are  disposed  at  regular  distances  along  the  ridges  of 
the  cuticle,  and  give  rise  to  the  appearance  of  lines  cutting  the  ridges 
transversely. 


CHAPTER   X. 


OF  THE  VISCERA. 


That  part  of  the  science  of  anatomy  which  treats  of  the  viscera 
is  named  splanchnology,  from  the  Greek  words  dntXayxyov,  viscus, 
and  Koyos-  The  viscera  of  the  human  body  are  situated  in  the  three 
great  internal  cavities, — the  cranio-vertebral,  thorax,  and  abdo- 
men. The  viscera  of  the  cranio-vertebral  cavity — the  brain  and 
spinal  cord,  with  the  principal  organs  of  sense  have  been  already 
described,  in  conjunction  with  the  nervous  system.  The  viscera 
of  the  chest  are — the  central  ^rgan  of  circulation,  the  heart;  the 
organs  of  respiration,  the  lungs;  and  the  thymus  gland.  The 
abdominal  viscera  admit  of  a  subdivision  into  those  which  properly 
belong  to  that  cavity,  viz.  the  alimentary  canal,  liver,  pancreas, 
spleen,  kidneys,  and  supra-renal  capsules,  and  those  of  the  pelvis — 
the  bladder  and  internal  organs  of  generation. 


THORAX. 


The  thorax  is  the  conical  cavity,  situated  at  the  upper  part  of 
the  trunk  of  the  body ;  it  is  narrow  above  and  broad  below,  and  is 
bounded  in  front  by  the  sternum,  six  superior  costal  cartilages, 
ribs,  and  intercostal  muscles ;  laterally,  by  the  ribs  and  intercostal 
muscles;  and,  behind,  by  the  same  structures,  and  by  the  vertebral 
column,  as  low  down  as  the  upper  border  of  the  last  rib  and  the 
first  lumbar  vertebra ;  superiorly,  by  the  thoracic  fascia  and  first 
ribs;  and,  inferiorly,  by  the  diaphragm.  It  is  much  deeper  on  the 
posterior  than  on  the  anterior  wall,  in  consequence  of  the  obliquity 
of  the  diaphragm,  and  contains  the  heart,  enclosed  in  its  pericar- 
dium, with  the  great  vessels;  the  lungs,  with  their  serous  cover- 
ings, the  pleurtG ;  the  oesophagus  ;  some  important  nerves ;  and,  in 
the  foetus,  the  thymus  gland, 

THE    HEART. 

The  central  organ  of  circulation,  the  heart,  is  situated  between 
the  two  layers  of  pleura,  which  constitute  the  mediastinum,  and  is 
enclosed  in  a  proper  membrane,  the  pericardium. 

Pericardium. — The  pericardium  is  a  fibro-serous  membrane  like 
the  dura  mater,  and  resembles  that  membrane  in  deriving  its  serous 
layer  from  the  reflected  serous  membrane  of  the  viscus  which 
it  encloses.  It  consists,  therefore,  of  two  layers,  an  external  fibrous 
and  an  internal  serous.  The  fibrous  layer  is  attached  above,  to  the 
great  vessels  at  the  root  of  the  heart,  where  it  is  continuous  with 

42* 


498 


PERICARDIUM. 


the  thoracic  fascia;  and  below  to  the  tendinous  portion  of  the  dia- 
phragm.    The  serous  membrane  invests  the  heart  with  the  com- 
mencement of  its  great  vessels, 
Fig.  174,  and  is  then  reflected   upon  the 

internal  surface  of  the  fibrous 
layer. 

The  heart  is  placed  obliquely 
in  the  chest,  the  base  being  di- 
rected upwards  and  backwards 
towards  the  right  shoulder;  the 
apex  forwards,  and,  to  the  left, 
points  to  the  space  between  the 
fifth  and  sixth  ribs,  at  about  two 
or  three  inches  from  the  ster- 
num. Its  under  side  is  flatten- 
ed, and  rests  upon  the  tendinous 
portion  of  the  diaphragm ;  its 
-upper  side  is  rounded  and  con- 
vex, and  formed  principally  by 
the  right  ventricle,  and  partly 
by  the  left.  Surmounting  the  ventricles  are  the  corresponding  auri- 
cles, whose  auricular  appendages  are  directed  forwards,  and  shghtly 
overlap  the  root  of  the  pulmonary  artery.  The  pulmonary  artery  is 
the  large  anterior  vessel  at  the  root  of  the  heart ;  it  crosses  obliquely 
the  commencement  of  the  aorta.  The  heart  consists  of  two  auricles 
and  two  ventricles,  which  are  respectively  named,  from  their  position, 
right  and  left.  The  right  is  the  venous  side  of  the  heart;  it  receives 
into  its  auricle  venous  blood  from  every  part  of  the  body,  by  the  supe- 
rior and  inferior  cava  and  coronary  vein.     From  the  auricle  the 

Y'lg.  174.  The  anatomy  of  the  heart.  1.  The  right  auricle.  2.  Tiie  entrance  of 
the  superior  vena  cava.  3.  The  entrance  of  the  inferior  cava.  4.  The  opening  of  the 
coronary  vein,  half  closed  by  the  coronary  viilve.  5.  The  Eustachian  valve.  6.  The 
fossa  ovalis,  surrounded  by  the  annulus  ovalis.  7.  The  luberculum  Loweii.  8.  The 
muscuii  pectinati  in  tlie  appendix  auriculae.  9.  The  auriculo-ventiicular  opening. 
10.  The  cavity  of  the  right  ventricle.  11.  The  tricuspid  valve,  attached  by  the  chordse 
tendinea;  to  the  carnejE  columnae  (12).  13.  The  pulmonary  artery,  guarded  at  its  com- 
mencement by  three  semilunar  valves.  14.  The  right  pulmonary  artery,  passing  be- 
neatli  the  arch  and  behind  the  asuending  aorta.  15.  The  left  pulmonary  artery,  cross- 
ing in  front  of  the  descending  aorta.  *  The  remains  of  the  ductus  arteriosus,  acting 
as  a  ligament  between  the  pulmonary  artery  and  arch  of  the  aorta.  The  arrows  mark 
the  course  of  the  venous  blood  through  the  right  side  of  the  lieart.  Entering  the  auri- 
cle by  tlie  superior  and  inferior  cavne,  it  [)asses  through  the  auriculo-ventricular  open- 
ing into  the  ventricle,  and  thence  through  the  pulmonary  artery  to  the  lungs.  16.  The 
left  auricle.  17.  The  openings  of  tlie  four  pulmonary  veins.  18.  The  auriculo-ventri- 
cular opening.  19.  The  left  ventricle.  20.  The  mitral  valve,  attached  by  its  cliordse 
tendincfe  to  two  large  columna3  carnew,  which  project  from  the  walls  of  the  ventricle, 
21.  The  commencement  and  course  of  the  ascending  aorta  behind  the  pulmonary 
artery,  marked  by  an  arrow.  The  entrance  of  the  vessel  is  guarded  by  three  semi- 
lunar valves.  22.  The  arch  of  the  aorta.  The  comparntivc  thickness  of  tlie  two  ven- 
tricles is  shown  in  the  diagram.  The  course  of  the  pure  blood  through  the  left  side  of 
the  heart  is  marked  by  arrows.  The  blood  is  brought  from  the  lungs  by  the  four 
pulmonary  veins  into  the  left  auricle,  and  passes  through  the  auriculo-ventricular 
opening  into  the  Icfl  ventricle,  whence  it  is  conveyed  by  the  aorta  to  every  part  of 
the  body. 


OPENINGS  OF  THE  HEART.  499 

blood  passes  into  the  ventricle,  and  from  the  ventricle  through  the 
pulmonary  artery,  to  the  capillaries  of  the  lungs.  From  these  it  is 
returned  as  arterial  blood  to  the  left  auricle;  from  the  left  auricle 
it  passes  into  the  left  ventricle;  and  from  the  left  ventricle  is  carried 
through  the  aorta,  to  be  distributed  to  every  part  of  the  body,  and 
again  returned  to  the  heart  by  the  veins.  This  constitutes  the  course 
of  the  adult  circulation. 

The  heart  is  best  studied  in  situ.  If,  however,  it  be  removed 
from  the  body,  it  should  be  placed  in  tf)e  position  indicated  in  the 
above  description  of  its  situation.  A  transverse  incision  should  then 
be  made  along  the  ventricular  margin  of  the  right  auricle,  from  the 
appendix  to  its  right  border,  and  crossed  by  a  perpendicular  incision, 
carried  from  the  side  of  the  superior  to  the  inferior  cava.  The 
blood  must  then  be  removed.  Some  fine  specimens  of  white  fibrin 
are  frequently  found  with  the  coagula ;  occasionally  they  are 
yellow  and  gelatinous.  This  appearance  deceived  the  older  anato- 
mists, who  called  these  substances  "  polypus  of  the  heart:"  they  are 
also  frequently  found  in  the  right  ventricle,  and  sometimes  in  the 
left  cavities. 

The  Right  Auricle  is  larger  than  the  left,  and  is  divided  into  a 
principal  cavity  or  sinus,  and  an  appendix  auriculse.  The  interior 
of  the  sinus  presents  for  examination  five  openings;  two  valves; 
tw9  relics  of  foetal  structure;  and  two  peculiarities  in  the  proper 
structure  of  the  auricle.     They  may  be  thus  arranged : 

Superior  cava, 
Inferior  cava, 
Openings    .     .     .     •     •  ,•     K  Coronary  vein. 

Foramina  Thebesii, 
Auriculo-ventricular  opening. 

(  Eustachian  valve, 
I  Coronary  valve. 


Valves 

r,  T       r  X'  t  1  .      4  \  Annulus  ovalis, 

Relics  of  fcetal  structure    ■      l  -r^  v 

^  ^  (  Jb  ossa  ovahs. 

Structure  of  the  Auricle     .      ^  n^       V        -•     !•   ^'' 

•^  I  iVlusculi  pectinali. 

The  Superior  cava  returns  the  blood  from  the  upper  half  of  the 
body,  and  opens  into  the  upper  and  front  part  of  the  auricle. 

The  Inferior  cava  returns  the  blood  from  the  lower  half  of  the 
body,  and  opens  into  the  lower  and  posterior  wail,  close  to  the  par- 
tition between  the  auricles  (septum  auriculorum).  The  direction  of 
these  two  vessels  is  such,  that  a  stream  forced  through  the  superior 
cava  would  be  directed  towards  the  auriculo-ventricular  opening. 
In  like  manner,  a  stream  rushing  upwards  by  the  inferior  cava 
would  force  its  current  against  the  septum  ain-iculorum ;  this  is  the 
proper  direction  of  the  two  currents  during  foetal  life. 

The  Coronary  vein  returns  the  venous  blood  from  the  substance 


500  VALVES OPENINGS. 

of  the  heart;  it  opens  into  the  auricle  between  the  inferior  cava 
and  the  auriculo-ventricular  opening,  under  cover  of  the  coronary 
valve. 

The' Fm-amin a  Thehesii*  are  nninute  pore-Uke  openings,  by  which 
the  venous  blood  exhales  directly  from  the  muscular  structure  of  the 
heart  into  the  auricle,  without  entering  the  venous  current.  These 
openings  are  also  found  in  the  left  auricle,  and  in  the  right  and  left 
ventricles. 

The  Auriculo-ventricular  opening  is  the  large  opening  of  com- 
munication between  the  auricle  and  ventricle. 

The  Eust(icliian-\  valve  is  a  part  of  the  apparatus  of  foetal  cir- 
culation, and  serves  to  direct  the  placental  blood  from  the  inferior 
cava,  through  the  foramen  ovale  into  the  left  auricle.  In  the  adult 
it  is  a  mere  vestige  and  imperfect,  though  sometimes  it  remains  of 
large  size.  It  is  formed  by  a  fold  of  the  lining  membrane  of  the 
auricle,  containing  some  muscular  fibres,  is  situated  between  the 
opening  of  the  inferior  cava  and  the  auriculo-ventricular  opening, 
and  is  generally  connected  with  the  coronary  valve. 

The  Coronary  valve  is  a  semilimar  fold  of  the  lining  membrane, 
stretching  across  the  mouth  of  the  coronary  vein,  and  preventing 
the  reflux  of  the  blood  in  the  vein  during  the  contraction  of  the 
auricle. 

The  Annulus  ovalis  is  situated  on  the  septum  auriculorum,  oppo- 
site the  termination  of  the  inferior  cava.  It  is  the  rounded  margin 
of  the  septum,  which  occupies  the  place  of  the  foramen  ovale  of 
the  foetus. 

The  Fossa  ovalis  is  an  oval  depression  corresponding  with  the 
foramen  ovale  in  the  foetus.  This  opening  is  closed  at  birth  by  a 
thin  valvular  layer,  which  is  continuous  with  the  left  margin  of  the 
annulus  and  is  frequently  imperfect  at  its  upper  part.  The  depres- 
sion or  fossa  in  the  right  auricle  results  from  this  arrangement. 
There  is  no  fossa  ovalis  in  the  left  auricle. 

The  Tuhnrculum  LoioeriX  is  the  portion  of  auricle  intervening  be- 
tween the  openings  of  the  superior  and  inferior  cava.  Being  thicker 
than  the  walls  of  the  veins  it  forms  a  projection,  which  was  supposed 
by  Lower  to  direct  the  blood  from  the  superior  cava  into  the  auri- 
culo-ventricular opening. 

The  Musculi  pectinati  are  small  muscular  columns  situated  in  the 
appendix  auriculae.  They  are  very  numerous,  and  are  arranged 
parallel  with  each  other ;  hence  their  cognomen,  '' pectinati,"  Wke 
the  teeth  of  a  comb. 

The  RIGHT  VENTRICLE  is  triangular  and  three-sided  in  its  form. 

*  AfJam  Christian  Thclorsiiis.  His  discovery  of  the  opcninfrs  now  known  by  his 
namn,  is  conliiincd  in  his  "  Dissertatio  Mcfiioa  de  Circulo  Sanjruinia  in  Corde,"  1708. 

+  Bartholomew  (Oustachins,  boin  at  Sun  Scvorino,  in  Naples,  was  Professor  of  Medi- 
cine in  Rome,  wlicrc  ho  di(!d  in  1570.  He  was  one  of  the  founders  of  modern  anatomy, 
and  the  first  who  ilhjstrated  his  works  with  <jood  eni^raviria-s  on  copper. 

t  Richard  [jower,  M.D.  "7'ractitns  de  C^orde ;  item  de  Mot'i  ct  Colore  Sanguinis," 
16G3.  His  dissections  were  made  upon  quadrupeds,  and  his  observations  relate  rather 
to  animals  than  to  rnan. 


EIGHT  VENTRICLE.  501 

Its  anterior  side  is  convex,  and  forms  the  larger  proportion  of  the 
front  of  the  heart.  The  inferior  side  is  flat,  and  rests  upon  the  dia- 
phragm :  and  the  inner  side  corresponds  with  the  partition  between 
the  two  ventricles,  septum  ventriculorum. 

The  right  ventricle  is  to  be  laid  open  by  making  an  incision  pa- 
rallel with,  and  a  little  to  the  right  of,  the  nriiddle  line,  from  the  pul- 
monary artery  in  front,  to  the  apex  of  the  heart,  and  thence  by  the 
side  of  the  middle  line  behind,  to  the  auriculo-ventricular  opening. 

It  contains,  to  be  examined,  two  openings,  the  auriculo-ventricular 
and  that  of  the  pulmonary  artery ;  two  apparatus  of  valves,  the 
tricuspid  and  semilunar;  and  a  muscular  and  tendinous  apparatus 
belonging  to  the  tricuspid  valves.     They  may  be  thus  arranged: 

Auriculo-ventricular  opening, 
Opening  of  the  pulmonary  artery. 
Tricuspid  valves, 
Semilunar  valves. 
Chordas  tendineae, 
Carnese  columnss. 

The  Auriculo-ventricular  opening  is  surrounded  by  a  fibrous  ring, 
covered  by  the  lining  membrane  of  the  heart.  It  is  the  opening  of 
communication  between  the  right  auricle  and  ventricle. 

The  Opening  of  the  ■pulmonary  artery  is  situated  close  to  the  sep- 
tum ventriculorum,  on  the  left  side  of  the  right  ventricle,  and  upon 
the  anterior  aspect  of  the  heart. 

The  Tricuspid  valves  are  three  triangular  folds  of  the  lining  mem- 
brane, strengihened  by  a  thin  layer  of  fibrous  tissue.  They  are 
connected  by  their  base  around  the  auriculo-ventricular  opening  ; 
and  by  their  sides  and  apices,  which  are  thickened,  they  give  at- 
tachment to  a  number  of  slender  tendinous  cords,  called  chordae 
tendineoe.  The  cliordcB  tendinece  are  the  tendons  of  the  thick  mus- 
cular columns  (columnce  carnea-)  which  stand  out  from  the  walls  of 
the  ventricle,  and  serve  as  muscles  to  the  valves.  A  number  of  these 
tendinous  cords  converge  to  a  single  muscular  attachment.  The 
tricuspid  valves  prevent  the  regurgitation  of  blood  into  the  auricle 
during  the  contraction  of  the  ventricle,  and  they  are  prevented  from 
being  themselves  driven  back,  by  the  chordae  tendiness  and  their 
muscular  attachments. 

This  connexion  of  the  muscular  columns  of  the  heart  to  the  valves 
has  caused  their  division  into  active  and  passive.  The  active  valves 
are  the  tricuspid  and  mitral ;  the  passive  the  mere  folds  of  lining 
membrane,  viz.  the  semilunar,  Eustachian,  and  coronary. 

Mr.  T.  W.  King,  of  Guy's  Hospital,  has  made  the  tricuspid 
valves  a  subject  of  special  investigation,  and  has  recorded  his  obser- 
vations in  a  very  interesting  paper*  in  the  Guy's  Hospital  Reports. 
The  valves  consist,  according  to  Mr.  King,  of  curtains,  cords,  and 

*  "Essay  on  tlie  Safety  Valve  Function  in  the  Right  Ventricle  of  the  Human  Heart," 
by  T.  W.  King.     Guy's  Hospital  Reports,  vol.  ii. 


502  COLUJIN.E  CARNEjE. 

columns.  The  anterior  valve  or  curtain  is  the  largest,  and  is  so 
placed  as  to  prevent  the  filHns;  of  the  pulmonary  artery  during  the 
distension  of  the  ventricle.  The  right  valve  or  curtain  is  of  smaller 
size,  and  is  situated  upon  the  right  side  of  the  auriculo-ventricular 
opening.  The  third  valve,  or  ''fixed  curtain"  is  connected  by  its 
cords  to  the  septum  ventriculoruni.  The  cor'ls  (chordae  tendinea) 
of  the  anterior  curtain  are  attached,  principally,  to  a  long  column 
(columna  carnea),  which  is  connected  with  the  "  right  or  thin  and 
yielding  ivall  of  the  ventricle."  From  the  lower  part  of  this  column 
a  transverse  muscular  band,  the  "  lovg  moderator  hand"  is  stretched 
to  the  septum  ventriculorum  or  "  solid  ivall"  of  the  ventricle.  The 
right  curtain  is  connected,  by  means  of  its  cords,  partly  with  the 
long  column,  and  partly  with  its  own  proper  column,  the  second 
column,  which  is  also  attached  to  the  "yielding  loalV  of  the  ven- 
tricle. A  third  and  smaller  column  is  generally  connected  with  the 
right  curtain.  The  "fixed  curtain"  is  named  from  its  attachment  to 
the  "solid  ivall"  of  the  ventricle,  by  means  of  cords  only,  without 
fleshy  columns. 

From  this  remarkable  arrangement  of  the  valves  it  follows,  that 
if  the  right  ventricle  be  over  distended,  the  thin  or  "yielding  ivall" 
will  give  way,  and  carry  with  it  the  columns  of  the  anterior  and 
right  valves.  The  cords  connected  with  these  columns  will  draw 
down  the  edges  of  the  corresponding  valves,  and  produce  an  open- 
ing between  the  curtains,  through  which  the  superabimdant  blood 
may  escape  into  the  auricle,  and  the  ventricle  be  relieved  from 
over-pressure.  This  beautiful  mechanism  is  therefore  adapted,  to 
fulfil  the  "  function  of  a  safety  valve." 

The  Columnar  carnecE  (fleshy  columns)  is  a  name  expressive  of 
the  appearance  of  the  internal  walls  of  the  ventricles,  which  seem 
formed  of  muscular  columns  interlacing  in  almost  every  direction. 
They  are  divided  into  three  sets,  according  to  the  manner  of  their 
connexion.  1.  The  greater  number  are  attached  by  the  whole  of 
one  side,  and  merely  form  convexities  into  the  cavity  of  the  ven- 
tricle. 2.  Others  are  connected  by  both  extremities,  being  free  in 
the  middle.  3.  A  few  (columnse  papillares)  are  attached  by  one 
extremity  to  the  walls  of  the  heart,  and  by  the  other  give  insertion 
to  the  chordae  tendinese. 

The  Semilunar  valves,  three  in  number,  are  situated  around  the 
commencement  of  the  pulmonary  artery,  being  formed  by  a  folding 
of  its  lining  membrane,  strengthened  by  a  thin  layer  of  fibrous  tissue. 
They  are  attached  by  their  convex  borders,  and  free  by  the  con- 
cave, which  are  directed  upwards  in  the  course  of  the  vessel,  so  that, 
during  the  current  of  the  blood  along  the  artery  they  are  pressed 
against  the  sides  of  the  cylinder;  but  if  any  attern[)t  at  regurgitation 
ensue  they  are  immediately  expanded,  and  effectually  close  the 
entrance  of  the  lube.  The  mai'gins  of  the  valves  are  thicker  than 
the  rest  of  their  extent,  and  each  valve  presents  in  the  centre  of  this 


LEFT  AURICLE  AND  VENTRICLE.  503 

margin  a  small  fibro-cartilaginous  tubercle,  called  cor-pus  Jlrantii,* 
which  locks  in  with  the  two  others  during  the  closure  of  the  valves, 
and  secures  the  triangular  space  that  would  otherwise  be  left  by  the 
approximation  of  three  semilunar  folds. 

Between  the  semilunar  valves  and  the  cylinder  of  the  artery  are 
three  pouches,  called  the  ■pulmonary  sinuses.  Similar  sinuses  are 
situated  behind  the  valves  at  the  commencement  of  the  aorta,  and 
are  much  larger  and  more  capacious  than  those  of  the  pulmonary 
artery. 

The  Pulmonary  artery  commences  by  a  scalloped  border,  corre- 
sponding with  the  three  valves  which  are  attached  along  its  edge. 
It  is  connected  to  the  ventricle  by  muscular  fibres,  and  by  the  lining 
membrane  of  the  heart. 

The  Left  Auricle  is  somewhat  smaller  than  the  right ;  of  a 
cuboid  form,  and  situated  more  posteriorly.  The  appendix  ouriculcB 
is  constricted  at  its  junction  with  the  auricle,  and  has  an  arborescent 
appearance;  it  is  directed  forwards  towards  the  root  of  the  pul- 
.  monary  artery,  to  which  the  auriculas  of  both  sides  appear  to  con- 
verge. 

The  left  auricle  is  to  be  laid  open  by  a  -"-  shaped  incision,  the 
horizontal  section  being  made  along  the  border  which  is  attached  to 
the  base  of  the  ventricle. 

It  presents  for  examination  five  openings,  and  the  muscular  struc- 
ture of  the  appendix;  these  are, — 

Four  pulmonary  veins, 
A.uriculo-ventricular  opening, 
Musculi  pectinati. 

The  Pulmonary  veins,  two  from  the  right  and  two  from  the  left 
lung,  open  into  the  corresponding  sides  of  the  auricle.  The  two  left 
pulmonary  veins  terminate  frequently  by  a  common  opening. 

The  Auriculo-ventricular  opening  is  the  aperture  of  communica- 
tion between  the  auricle  and  ventricle. 

The  Musculi  pectinali  are  fewer  in  number  than  in  the  right 
auricle,  and  are  situated  only  in  the  appendix  auriculae. 

Left  Ventricle. — The  left  ventricle  is  to  be  opened,  by  making 
an  incision  a  little  to  the  left  of  the  septum  ventriculorum,  and  con- 
tinuing it  around  the  apex  of  the  heart,  to  the  auriculo-ventricular 
opening  behind. 

The  left  ventricle  is  conical,  both  in  external  figure  and  in  the 
form  of  its  internal  cavity.  It  forms  the  apex  of  the  heart,  by  pro- 
jecting beyond  the  right  ventricle,  while  the  latter  has  the  advantage 
in  length  towards  the  base.  Its  walls  are  about  seven  lines  in  thick- 
ness, those  of  the  right  ventricle  being  about  two  lines  and  a  half. 

It  presents  for  examination,  in  its    interior,  two  openings,  two 

*  Julius  Coesar  Arantius,  Professor  of  Medicine  in  Bolofifna.  Ho  was  a  disciple  of 
Vcsaliubi,  one  of  the  founders  of  modern  anatomy.  His  treatise  "  De  Ilumani  Fretu," 
was  published  at  Rome,  in  1564. 


504  STRUCTURE  OF  THE  HEART. 

valves,  and  the  tendinous  cords  and  nriuscular  colun:ins ;  they  may 
be  thus  arransjed : 

Auriculo-ventricular  opening, 
Aortic  opening. 

Mitral  valves, 
Semilunar  valves. 

Chordae  tendinese, 
Columnse  earner. 

The  Auriculo-ve'ntricular  openivg  is  a  dense  fibrous  ring,  covered 
by  the  lining  membrane  of  the  heart,  but  sm.aller  in  size  than  that  of 
the  right  side. 

The  Mitral  valves  are  attached  around  the  auriculo-ventricular 
opening,  as  are  the  tricuspid  in  the  right  ventricle.  They  are  thicker 
than  the  tricuspid,  and  consist  of  only  two  segments,  of  which  the 
larger  is  placed  betw^een  the  auriculo-ventricular  opening  and  the 
commencement  of  the  aorta,  and  acts  the  part  of  a  valve  to  that 
foramen,  during  the  filling  of  the  ventricle.  The  difference  in  size 
of  the  two  valves,  bolh  being  triangular,  and  the  space  between 
them,  has  given  rise  to  the  idea  of  a  "  bishop's  mitre,^^  after  which 
they  are  named.  These  valves,  like  the  tricuspid,  are  furnished 
with  an  apparatus  of  tendinous  cords,  cliordce  tendinecB,  which  are 
attached  to  two  very  large  column ce  carnece. 

The  Columnce  carnece  admit  of  the  same  arrangement  into  three 
kinds,  as  on  the  right  side.  Those  which  are  free  by  one  extremity, 
the  columnar  papillares,  are  only  two  in  number,  and  much  larger 
than  those  on  the  opposite  side. 

The  Semilunar  values  are  placed  around  the  commencement  of 
the  aorta,  like  those  of  the  puh'nonary  artery  ;  "they  are  similar  in 
structure,  and  are  attached  to  the  scalloped  border  by  which  the 
aorta  is  connected  with  the  ventri(;le.  The  tubercle  in  the  centre 
of  each  fold  is  larger  than  those  in  the  pulmonary  valves,  and  it  was 
these  that  Arantius  particularly  described  ;  but  the  term  "  corpora 
AranLii.^'  is  now  applied  indiscriminately  to  both.  The  fossa?,  between 
the  semilunar  vnlves  and  the  cylinder  of  the  artery  are  much  larger 
than  those  of  the  pulmonary  artery ;  they  are  called  the  "  sinus 
aortici." 

STRUCTURE    OF    THE    HEART. 

The  arrangement  of  the  fibres  of  the  heart  has  been  made  the 
subject  of  careful  and  accurate  investigation  by  Mr.  Searle,  to 
whose  excellent  article,  "Fibres  of  the  Heart,"  in  the  Cyclopaedia 
of  Anatomy  and  Physiology,  I  am  indebted  for  the  following  sum"- 
mary  of  their  distribution : 

For  the  sake  of  clearness  of  description  the  fibres  of  the  ventri- 
cles have  been  divided  into  three  layers, — superficial,  middle,  and 
internal — all  of  which  are  disposed  in  a  spiral  direction  around  the 
cavities  of  the  ventricles.     The   mode  of  formation  of  these  three 


FIBRES  OF  THE  VENTRICLES.  505 

layers  will  be  best  iinderstood  by  adopting  the  plan  pursued  by  Mr. 
Searle  in  tracing  the  course  of  the  fibres  from  the  centre  of  the 
heart  towards  its  periphery. 

The  left  surface  of  the  septum  ventriculorum  is  formed  by  a 
broad  and  thick  layer  of  fibres,  which  proceed  backwards  in  a  spiral 
direction  around  the  posterior  aspect  of  the  left  ventricle,  and 
become  augmented  on  the  left  side  of  that  ventricle,  by  other  fibres 
derived  from  the  bases  of  the  two  columnse  papillares.  The  broad 
and  thick  band  formed  by  the  fibres  from  these  two  sources,  curves 
around  the  apex  and  lower  third  of  the  left  ventricle,  to  the  anterior 
border  of  the  septum,  where  it  divides  into  two  bands, — a  short  or 
apicial  band,  and  a  long  or  basial  band. 

The  Sfwrt  or  apicial  band  is  increased  in  thickness  at  this  point 
by  receiving  a  layer  of  fibres  (derived  from  the  root  of  the  aorta 
and  carnece  columnee)  upon  its  internal  surface,  from  the  right  sur- 
face of  the  septum  ventriculorum ;  it  is  then  continued  onwards  in 
a  spiral  direction  from  left  to  right,  around  the  lower  third  of  the 
anterior  surface,  and  the  middle  third  of  the  posterior  surface  of 
the  right  ventricle  to  the  posterior  border  of  the  septum.  From  the 
latter  point  the  short  band  is  prolonged  around  the  posterior  and 
outer  border  of  the  left  ventricle  to  the  anterior  surface  of  the  base 
of  that  ventricle,  and  is  inserted  into  the  anterior  border  of  the  left 
auriculo-ventricular  ring,  and  the  anterior  part  of  the  root  of  the 
aorta  and  pulmonary  artery. 

The  Lovg  or  basial  band,  at  the  anterior  border  of  the  septum, 
passes  directly  backwards  through  the  septum,  forming  its  middle 
layer,  to  the  posterior  ventricular  groove,  where  it  becomes  joined 
by  fibres  derived  from  the  root  of  the  pulmonary  artery.  It  then 
winds  spirally  around  the  middle  and  upper  third  of  the  left  ven- 
tricle to  the  anterior  border  of  the  septum,  where  it  is  connected  by 
means  of  ils  internal  surface  with  the  superior  fibres  derived  from 
the  aorta,  which  form  part  of  the  right  wall  of  the  septum.  From 
this  point  it  is  continued  around  the  upper  third  of  the  anterior  and 
posterior  surface  of  the  right  ventricle  to  the  posterior  border  of 
the  septum,  where  it  is  connected  with  the  fibres  constituting  the 
right  surface  of  the  septum  ventriculorum.  At  the  latter  point  the 
fibres  of  this  band  begin  to  be  twisted  upon  themselves,  like  the 
strands  of  a  rope,  the  direction  of  the  twist  being  from  below  up- 
wards. This  arrangement  of  fibres  is  called,  by  Mr.  Searle,  *'  the 
rope;"  it  is  continued  spirally  upwards,  forming  the  brim  of  the 
left  ventricle,  to  the  anterior  surface  of  the  base  of  that  ventricle, 
where  the  twisting  of  the  fibres  ceases.  The  long  band  then  curves 
inwards  towards  the  septum,  and  spreads  out  upon  the  left  surface 
of  the  septum  into  the  broad  and  thick  layer  of  fibres  with  which 
this  description  commenced. 

The  most  inferior  of  the  fibres  of  the  left  surface  of  the  septum 
ventriculorum,  after  winding  spirally  around  the  internal  surface  of 
the  apex  of  the  left  ventricle,  so  as  to  close  its  extremity,  form  a 
small  fasciculus,  which  is  excluded  from  the  interior  of  the  ventricle, 

43 


506  FIBRES  OF  THE  ACRICLES. 

and  expands  in  a  radiated  manner  over  the  surface  of  the  heart, 
constituting  its  superficial  layer  of  fibres.  The  direction  of  these 
fibres  is,  for  the  most  part,  oblique,  passing  from  left  to  right  on  the 
anterior,  and  from  right  to  left  on  the  posterior  surface  of  the  heart, 
becoming  more  longitudinal  near  its  base,  and  terminating  by  being 
inserted  into  the  fibrous  rings  of  the  auriculo-ventricnlar  openings, 
and  of  the  pulmonary  artery  and  aorta.  Over  the  right  ventricle 
the  superficial  fibres  are  increased  in  number  by  the  addition  of 
accessory  fibres  from  the  right  surface  of  the  septum,  which  pierce 
the  middle  layer,  and  take  the  same  direction  with  the  superficial 
fibres  from  the  apex  of  the  left  ventricle,  and  of  other  accessory 
fibres  from  the  surface  of  both  ventricles. 

From  this  description  it  will  be  perceived,  that  the  superficial 
layer  of  fibres  is  very  scanty,  and  is  pretty  equally  distributed  over 
the  surface  of  both  ventricles.  The  middle  layer  of  both  ventricles 
is  formed  by  the  two  bands,  short  and  long.  But  the  internal  layer 
of  the  two  ventricles  is  very  differently  constituted  :  that  of  the  left 
is  formed  by  the  spiral  expansion  of  the  fibres  of  the  rope,  and  of 
the  two  columnae  papillares;  that  of  the  right  remains  to  be  described. 
The  septum  ventriculorum  also  consists  of  three  layers,  a  left  layer, 
the  radiated  expansion  of  the  rope  and  carneas  columnse ;  a  middle 
layer,  the  long  band  ;  and  a  right  layer,  belonging  to  the  proper  wall 
of  the  right  ventricle,  and  continuous  both  in  front  and  behind  with 
the  long  band,  and  in  front  also  with  the  short  band,  and  with  the 
superficial  layer  of  the  right  ventricle. 

The  Intey^nal  layer  of  the  right  ventricle  is  formed  by  fasciculi 
of  fibres  which  arise  from  the  right  segment  of  the  root  of  the  aorta, 
from  the  entire  circumference  of  the  root  of  the  pulmonary  artery, 
and  from  the  bases  of  the  columnee  papillares.  The  fibres  from 
the  root  of  the  aorta,  associated  with  some  from  the  carneas  columnae, 
constitute  a  layer  which  passes  obliquely  forwards  upon  the  right 
side  of  the  septum.  The  superior  fibres  coming  directly  from  the 
aorta  join  the  internal  surface  of  the  long  band  at  the  anterior  bor- 
der of  the  septum,  while  the  lower  two-thirds  of  the  layer  are  con- 
tinuous with  the  internal  surface  of  the  short  band,  some  of  its 
fibres  piercing  that  band  to  augment  the  number  of  superficial 
fibres.  The  fibres  derived  from  the  root  of  the  pulmonary  artery, 
conjoined  with  those  from  the,base  of  one  of  the  columnae  papillares, 
curve  forwards  from  their  origin,  and  wind  obliquely  downwards 
and  backwards  around  the  internal  surface  of  the  wall  of  the  ven- 
tricle to  the  posterior  border  of  the  septum,  where  they  become 
continuous  with  the  long  band,  directly  that  it  has  passed  backwards 
through  the  septum. 

Fibres  of  the  Auricles. — The  fibres  of  the  auricles  are  disposed  in 
two  layers,  external  and  internal.  The  internal  layer  is  formed  of 
fasciculi  which  arise  from  the  fibrous  rings  of  the  auriculo-ventri- 
cular  openings,  and  proceed  upwards  to  enlace  with  each  oiher, 
and  constitute  the  appendices  auriculorum.  These  fasciculi  are 
parallel  in  their  arrangement,  and  in  the  appendices  form  projec- 


ORGANS  OF  RESPIRATION  AND  VOICE.  507 

tions  and  give  rise  to  the  appearance  which  is  denominated  mus- 
cuU  pectinati.  In  their  course  they  give  off  branches  which  con- 
nect adjoining  fasciculi,  and  fornn  a  columnar  interlacement  between 
them. 

External  Layer. — The  fibres  of  the  right  auricle  having  com- 
pleted the  appendix,  wind  from  left  to  right  around  the  right  border 
of  this  auricle,  and  along  its  anterior  aspect,  beneath  the  appendix, 
to  the  anterior  surface  of  the  septum.  From  the  septum  they  are 
continued  to  the  anterior  surface  of  the  left  auricle,  where  they 
separate  into  three  bands, — superior,  anterior,  and  posterior.  The 
superior  band  proceeds  onwards  to  the  appendix,  and  encircles  the 
apex  of  the  auricle.  The  anterior  band  passes  to  the  left,  beneath 
the  appendix,  and  winds  a  broad  layer  completely  around  the  base 
of  the  auricle,  and  through  the  septum  to  the  root  of  the  aorta,  to 
which  it  is  partly  attached,  and  from  this  point  is  continued  onwards 
to  the  appendix,  where  its  fibres  terminate  by  interlacing  with  the 
musculi  pectinati.  The  posterior  band  crosses  the  left  auricle 
obhquely  to  its  posterior  part,  and  winds  from  left  to  right  around 
its  base,  encircling  the  openings  of  the  pulmonary  veins;  some  of 
its  fibres  are  lost  upon  the  surface  of  the  auricle,  others  are  con- 
tinued onwards  to  the  base  of  the  aorta ;  and  a  third  set,  forming  a 
small  band,  is  prolonged  along  the  anterior  edge  of  the  appendix  to 
its  apex,  where  it  is  continuous  with  the  superior  band.  The  sep- 
tum auriculorum  has  four  sets  of  fibres  entering  into  its  formation ; 
1.  The  fibres  arising  from  the  auriculo-ventricular  rings  at  each 
side;  2.  Fibres  arising  from  the  root  of  the  aorta,  which  pass 
upwards  to  the  transverse  band,  and  to  the  root  of  the  superior 
cava;  H.  Those  fibres  of  the  anterior  band  that  pass  through  the 
lower  part  of  the  septum  in  their  course  around  the  left  auricle ; 
and  4.  A  slender  fasciculus,  which  crosses  through  the  septum 
from  the  posterior  part  of  the  right  auriculo-ventricular  ring  to  the 
left  auricle. 

It  will  be  remarked  from  this  description,  that  the  left  auricle  is 
considerably  thicker  and  more  muscular  than  the  right. 

Vessels  and  Nerves. — The  Arteries  supplying  the  heart  are  the 
anterior  and  posterior  coronary. 

The  Veins  accompany  the  arteries,  and  empty  themselves  by 
the  common  coronary  vein  into  the  right  auricle.  The  lymphatics 
terminate  in  the  glands  about  the  root  of  the  heart.  The  nerves 
of  the  heart  are  derived  from  the  cardiac  plexuses,  which  are 
formed  by  communicating  filaments  from  the  sympathetic  and 
pneumogastric. 

ORGANS   OF   RESPIRATION    AND   VOICE. 

The  organs  of  respiration  are  the  two  lungs,  with  their  air-tube, 
the  trachea,  to  the  upper  part  of  which  is  adapted  an  apparatus  of 
cartilages,  constituting  the  organ  of  voice,  or  larynx. 


508 


THE  LARYNX. 


THE    LARYNX. 


The  Larynx  is  situated  at  the  forepart  of  the  neck,  between  the 
trachea,  and  at  the  base  of  the  tongue.  It  is  composed  oi  cartilages, 
ligaments,  muscles,  vessels,  and  nerves,  and  mucous  membrane. 

The  Cartilages  are  the — 

Thyroid, 

Cricoid, 

Two  Arytenoid, 

Epiglottis. 

The  Thyroid  (Sugsoj — sT^ag,  hke  a  shield)  is  the  largest  cartilage  of 
the  larynx :  it  consists  of  two  lateral  portions,  or  alee,  which  meet 
at  an  acute  angle  in  front,  and  form  the  projection  which  is  known 
by  the  name  of  'pomum  Adami.  Where  the  pomum  Adami  is  pro- 
minent, a  bursa  mucosa  is  often  found  between  it  and  the  skin. 

Each  ala  is  quadrilateral,  and  forms  a  rounded  border  poste- 
riorly, which  terminates  above,  in  the  superior  cornu,  and  below,  in 
the  inferior  cornu.  Upon  the  side  of  the  ala  is  an  oblique  line,  into 
"which  the  sterno-thyroid  muscle  is  inserted,  and  from  which  the 
thyro-hyoid  takes  its  origin.  Behind  this  is  a  vertical  line,  which 
gives  origin  to  the  inferior  constrictor  muscle.  In  the  receding 
angle,  formed  by  the  meeting  of  the  two  alee  upon  the  inner  side 
of  the  cartilage,  and  near  to  its  lower  border,  are  attached  the 
epiglottis,  the  chordse  vocales,  the  thyro-arytenoid,  and  thyro- 
epif^lottidean  muscles. 

The  Cricoid  (x^ixog — sTSos,  like  a  ring)  is  a  ring  of  cartilage,  nar- 
row in  front  and  broad  behind,  where  it  is  surmounted  by  two 
rounded  surfaces,  which  articulate  with  the  arytenoid  cartilages. 
Upon  the  middle  line,  posteriorly,  is  a  vertical  ridge,  which  gives 
attachment  to  the  oesophagus,  and  on  each  side  of  the  ridge  are  the 
depressions  which  lodge  the  crico-arytenoidei  postici  muscles.  On 
either  side  of  the  ring  is  a  glenoid  cavity,  which  articulates  with  the 
inferior  cornu  of  the  thyroid  cartilage. 

The  Arytenoid  cart'dages  (apurai'va,  a  pitcher,)*  two  in  number, 
are  triangular  in  form.  They  are  broad  below,  where  they  articu- 
late with  the  upper  border  of  the  cricoid,  and  give  attachment  to 
the  crico-arytenoidei  postici,  crico-arytenoidei  laterales,  and  thyro- 
arytenoidei  muscles,  and  chordce  vocales;  and  pointed  adove,  where 
they  articulate  with  two  little  curved  cartilages,  called  cornicula 
laryngis  (capitula  laryngis).  On  the  posterior  surface  they  are 
concave,  and  lodge  the  arytenoideus  muscle. 

*  This  dnrivalion  has  reference  to  the  appearance  of  both  cartilages  taken  together 
and  Covered  by  mucous  membrane.  In  animals,  which  were  the  principal  subjects  of 
dissection  among  the  ancients,  the  opening  of  the  larynx  with  the  arytenoid  cartilages 
bears  a  striking  rescinblunce  to  the  mouth  of  a  pitcher  having  a  large  spout. 


MUSCLES  OF  THE  LARYNX.  509 

The  Epiglottis  {lii\y'kwrk,  upon  the  tongue)  is  a  fibro-cartilage  of 
a  yellowish  colour,  studded  with  a  number  of  small  mucous  glands, 
"which  are  lodged  in  shallow  piis  upon  its  surface.  It  is  shaped  like 
a  cordate  leaf,  and  is  placed  immediately  in  front  of  the  opening  of 
the  larynx,  which  it  closes  completely  when  the  larynx  is  drawn  up 
beneath  the  base  of  the  tongue.  It  is  attached  by  its  point  to  the 
receding  angle,  between  the  two  alse  of  the  thyroid  cartilage. 

Two  small  cartilaginous  tubercles  (cuneiform)  are  often  found  in 
the  folds  of  the  mucous  membrane  which  bound  the  opening  of  the 
larynx  laterally. 

Ligaments. — The  Ligaments  of  the  larynx  are  numerous,  and 
may  be  arranged  into  four  groups  :  1.  Those  which  articulate  the 
thyroid  with  the  os  hyoides.  2.  Those  which  connect  it  with  the 
cricoid.  3.  Ligaments  of  the  arytenoid  cartilages.  4.  Ligaments 
of  the  epiglottis. 

L  The  ligaments  which  connect  the  thyroid  cartilage  with  the 
OS  hyoides  are  three  in  number: 

The  two  Thyroliyoidean  ligaments  pass  between  the  superior 
cornua  of  the  thyroid  and  the  extremities  of  the  greater  cornua  of 
the  OS  hyoides  :  a  sesamoid  bone  is  found  in  each. 

The  Thyro-hyoidean  membrane  is  a  broad  membranous  layer, 
occupying  the  entire  space  between  the  thyroid  cartilage  and  os 
hyoides.     It  is  pierced  by  the  superior  laryngeal  nerve  and  artery. 

2.  The  ligaments  connecting  the  thyroid  to  ihe  cricoid  cartilage 
are  also  three  in  number: — 

Two  Capsular  ligaments,  with  their  synovial  membranes,  which 
form  the  articulation  between  the  inferior  cornua  of  the  thyroid  and 
the  sides  of  the  cricoid,  and  the  aico-thyroidean  membrane,  through 
which  the  operation  of  laryngotomy  is  performed,  fi'he  latter  is 
generally  crossed  by  a  small  artery,  the  inferior  laryngeal. 

3.  The  ligaments  of  the  arytenoid  cartilages  are  four  in  number: 
Two  Capsular  ligaments,  and  synovial  membranes,  which  arti- 
culate the  arytenoid  cartilages  with  the  cricoid  ;  and  the  thyro- 
arytenoid ligaments,  or  chordcB  vocaJes,  which  pass  backwards  from 
the  receding  angle  of  the  thyroid  cartilage,  near  to  its  lower  border, 
to  be  inserted  into  the  bases  of  the  arytenoid  cartilages.  The  space 
between  these  two  ligaments  is  the  glottis,  or  rima  glottidis. 

4.  The  ligaments  of  the  epiglottis  are  five  in  number  : — 

1.  Three  folds  of  mucous  membrane,  one  at  the  middle,  and  one 
at  each  side,  called  frana  epiglottidis,  which  hold  the  epiglottis 
back  to  the  tongue.  2.  Epiglotto-liyoidean  ligament,  which  connecis 
the  epiglottis  to  the  posterior  surface  of  the  os  hyoides.  3.  The 
ligament  which  attaches  the  epiglottis  to  the  receding  angle  of  the 
thyroid  cartilage. 

The  Muscles  of  the  larynx  are  eight  in  number:  the  five  larger 
are  the  muscles  of  the  chordcc  vocales  and  rima  glottidis;  the  three 
smaller  are  muscles  of  the  epiglottis. 

The  five  muscles  of  the  chordoe  vocales  and  rima  glottidis  are 
the— 

43* 


510 


LARYNX. 


Crico-thyroid, 

Crico-arytenoideus  posticus, 
Crico-arytenoideus  lateralis, 
Thyro-arytenoideus, 
Arytenoideus. 

Fig.  175. 


Fig.  176. 


The  Crico-thyroid  muscle  arises  from  the  anterior  surface  of  the 
cricoid  cartilage,  and  is  inserted  into  the  lower  and  inner  border  of 
the  thyroid. 

The  Crico-arytenoideus  posticus  arises  from  the  depression  on  the 
posterior  surface  of  the  cricoid  cartilage,  and  is  inserted  into  the 
outer  angle  of  the  base  of  the  arytenoid. 

The  Crico-arytenoideus  lateralis  arises  from  the  upper  border  of 
the  side  of  the  cricoid,  and  is  inserted  into  the  outer  angle  of  the 
base  of  the  arytenoid  cartilage. 

The  Thyro-arytenoideus  arises  hom  the  receding  angle  of  the  thy- 
roid cartilage,  close  to  the  outer  side  of  the  chorda  vocalis,  and 
passes  backwards  parallel  with  the  chord,  to  be  inserted  into  the 
base  of  the  arytenoid  cartilage. 

The  Arytenoideus  muscle  occupies  the  posterior  concave  surface 
of  the  arytenoid  cartilages,  between  which  it  is  stretched.  It  con- 
sists of  three  planes  of  transverse  and  oblique  fibres ;  hence  it  was 
formerly  considered  as  several  muscles,  under  the  names  of  trans- 
versi  and  obliqui. 

The  three  muscles  of  the  epiglottis  are  the — 
Thyro-epiglottideus, 
Aryieno-epigloltideus  superior, 
Aryteno-epiglottideus  inferior  (Hilton's  muscle). 

Fig.  175.  A  posterior  view  of  the  larynx.  1.  The  thyroid  carlilagc.  2.  One  of  its 
ascending  cornua.  3.  One  of  the  descending  cornua.  4,  7.  The  cricoid  cartilage. 
5,  5.  The  arytenoid  cartilages.  G.  The  arytenoideus  muscle,  consisting  of  oblique  and 
transverse  fasciculi.     7.  'J'he  crico-arytcnoidei  postici  muscles.     8.  Th(!  epiglottis. 

Fig.  176.  A  side  view  of  the  larynx,  one  ala  of  the  tJiyroid  cartilage  h;i8  been  re- 
moved. 1.  The  remaining  ala  of  the  thyroid  cartilage.  2.  One  of  the  arytenoid  car- 
tilages. 3.  One  of  the  cornicula  laryngis.  4.  The  cricoid  cartiLige.  5.  The  crico- 
arytenoideus  posticus  muscle.  G.  The  crico  arytenoideus  lateralis.  7.  The  thyro- 
arytenoideus.  8.  The  cricothyroidean  membrane.  9.  One  half  of  the  epiglottis.  10. 
The  upper  part  of  the  trachea. 


MUSCLES  OF  THE  LARYNX.  511 

The  T/iyro-epigJoUideus  appears  to  be  formed  by  ihe  upper  fibres 
of  the  thyro-arytenoideus  muscle;  they  spread  out  upon  the  external 
surface  of  the  sacculus  laryugis,  on  which  they  are  lost;  a  few  of 
the  anterior  fibres  being  continued  onwards  to  the  side  of  the  epi- 
glottis. 

The  Aryteno-epighttideus  superior  consists  of  a  few  scattered 
fibres,  which  pass  i'orwards  in  the  fold  of  mucous  membrane  form- 
ing the  lateral  boundary  of  the  entrance  into  the  larynx,  from  the 
apex  of  the  arytenoid  cartilage  to  the  side  of  the  epiglottis. 

The  Aryteno-epighttideus  ivferior. — This  muscle  was  discovered 
by  Mr.  Hilton,  and  is  very  important  in  relation  to  the  sacculus 
laryngis,  with  which  it  is  closely  connected.  It  may  be  found  by 
raising  the  mucous  membrane  immediately  above  the  ventricle  of 
the  larynx.  It  arises  by  a  narrow  and  fibrous  origin  from  the  ary- 
tenoid cartilage,  just  above  the  attachment  of  the  chorda  vocalis; 
and  passing  forwards,  and  a  little  upwards,  expands  over  the  upper 
half,  or  two-thirds  of  the  sacculus  laryngis,  and  is  inserted  by  a 
broad  attachment  into  the  side  of  the  epiglottis. 

Actions. — The  crico-thyroid  and  arytenoid  muscles  are  contractors 
of  the  rima  glottidis;  the  crico-arytenoideus  posticus  and  lateralis, 
and  the  thyro-arytenoideus,  are  dilators. 

The  crico-thyroid  muscles  elongate,  and  thereby  bring  together 
the  chordae  vocales,  by  drawing  the  thyroid  cartilage  downwards 
and  forwards;  their  posterior  attachment  at  the  arytenoid  cartilages 
being  fixed.  The  arytenoid  muscle  approximates  the  arytenoid  car- 
tilages, and  consequently  the  chordae  vocales  directly.  The  crico- 
thyroidei  postici  being  attached  to  the  outer  angles  of  the  bases  of 
the  arytenoid  cartilages,  draw  them  from  each  other,  and  stretch 
the  chordae  vocales.  Tiie  crico-arytenoidei  laterales  draw  the  ary- 
tenoid cartilages  from  each  other,  but  relax  the  chordae  vocales ; 
and  the  thyro-arytenoidei  increase  the  width  of  the  glottis,  by  directly 
relaxing  the  chordae  vocales. 

The  thyro-epiglottideus  acts  principally  by  compressing  the  glands 
of  the  sacculus  laryngis  and  the  sac  itself:  by  its  attachment  to  the 
epiglottis  it  would  act  feebly  upon  that  valve.  The  aryteno-epiglot- 
tideus  superior  serves  to  keep  the  mucous  membrane  of  the  sides  of 
the  opening  of  the  glottis  tense,  when  the  larynx  is  drawn  upwards, 
and  the  opening  closed  by  the  epiglottis.  Of  the  aryteno-epiglotti- 
deus,  the  "functions  appear  to  be,"  writes  Mr.  Hilton,  "to  compress 
the  subjacent  glands  which  open  into  the  pouch:  to  diminish  the 
capacity  of  that  cavity,  and  change  its  form  ;  and  to  approximate 
the  epiglottis  and  the  arytenoid  cartilage." 

Mucous  Membrane. — The  larypx  is  lined  by  the  mucous  mem- 
brane, which  is  continued  from  the  mouth  and  pharynx,  and  pro- 
longed onwards  through  the  trachea  and  bronchi  to  the  bronchial 
cells.  The  chordae  vocales  form  two  horizontal  projections  of  the 
mucous  meinbrane,  and  constitute  the  lateral  boundaries  of  the 
l^lotlis.  or  rima  glottidis.  Immediately  above  the  horizontal  projec- 
tion of  the  chorda  vocalis,  at  each  side,  is  a  depressed  fossa,  the 


512  MUCOUS  MEMBRANE  OF  THE  LARYNX. 

ventricle  of  the  larynx.  The  superior  boundary  of  the  ventricle  is 
an  arched  border  of  nnucous  membrane,  which  is  v'ery  incorrectly 
termed  the  superior  c/iorda  vocalis.  If  the  rounded  extremity  of  a 
probe  be  introduced  into  the  ventricle  of  the  larynx,  and  then  directed 
upwards,  it  will  enter  a  considerable  pouch,  Vv'hich  has  been  recently 
described  by  Mr.  Hilton  as  the  sacculus  laryngis.*  From  the  ven- 
tricle of  the  larynx  the  sacculus  is  continued  upwards,  nearly  as 
high  as  the  upper  border  of  the  thyroid  cartilage,  and  sometimes 
beyond  it.  When  dissected  from  the  interior  of  the  larynx  it  is 
found  covered  by  the  aryteno-epiglottideus  muscle  and  a  fibrous 
membrane,  W'hich  is  attached  to  the  superior  chorda  vocalis  below; 
to  the  epiglottis  in  front ;  and  to  the  upper  border  of  the  thyroid 
cartilage  above.  If  examined  from  the  exterior  of  the  larynx,  it 
will  be  seen  to  be  covered  by  the  thyro-epiglotiideus  muscle.  On 
the  surface  of  its  mucous  membrane  are  the  openings  of  sixty  or 
seventy  small  follicular  glands,  which  are  situated  in  the  sub-mucous 
tissue,  and  give  to  its  external  surface  a  rough  and  ill-dissected  ap- 
pearance. This  mucous  secretion  is  intended  for  the  lubrication  of 
the  chordse  vocales,  and  is  directed  upon  them  by  two  small  valvular 
folds  of  mucous  membrane,  which  are  situated  at  the  entrance  of 
the  sacculus. 

The  Fai trance  of  the  larynx  is  formed  by  two  folds  of  mucous 
membrane,  stretched  between  the  apices  of  the  arytenoid  cartilages 
and  the  sides  of  the  epiglottis.  The  arytenoid  glands  and  superior 
aryteno-epiglottidean  muscles  are  situated  within  these  folds. 

The  Glands  of  the  larynx  are,  1.  The  epiglottic — most  impro- 
perly named — for  it  consists  merely  of  a  mass  of  fat,  situated  be- 
tween the  convexity  of  the  epiglottis  and  the  thyro-hyoid  membrane. 
2.  The  arytenoid  glands,  some  small  granules  found  in  the  folds  of 
mucous  membrane  near  the  apex  of  the  arytenoid  cartilage. 

Vessels  and  Nerves. — The  Arteries  of  the  larynx  are  derived  from 
the  superior  and  inferior  thyroid.  The  nerves  are  the  superior 
laryngeal  and  recurrent  laryngeal ;  both  branches  of  the  pneumo- 
gastric.     The  two  nerves  communicate  with  each  other  freely;  but 

*  This  sac  was  discovered  and  described  by  Mr.  Hilton  before  he  was  aware  that  it 
had  jilroady  been  pointed  out  by  the  older  anatomists.  I  myself  made  a  dissection, 
which  I  still  possess,  of  the  same  sac  in  an  enlarged  state  during  tlie  month  of  August, 
1837,  without  any  knowledge  cither  of  Mr.  Hilton's  labours,  or  M'>rgagni's  account. 
The  sac  projected  considerably  above  the  upper  border  of  tlie  thyroid  cartilage,  and  the 
extrcmiiy  had  been  snipped  off  on  one  side  in  ihe  removal  of  the  muscles.  The  larynx 
was  presented  to  me  by  Dr.  George  Moore  of  Camberwell :  he  had  obtained  it  from  a 
child  who  died  of  bronchial  disease;  and  he  conceived  that  this  peculiar  disposition  of 
the  mucous  membrane  miglit  possibly  explain  some  of  the  symptoms  by  which  the  case 
was  accompanied.  Cruveiihicr  made  the  same  discovery  in  equal  ignorance  of  Mor- 
gagni's  dcHcrifition,  for  we  read  in  a  note  at  page  677,  vol.  ii.  of  his  Anotoniie  Descrip- 
tive,— ".I'ai  vu  pour  la  premit're  fois  cette  arricre  eavite  ehez  un  individu  iitfueti'  de 
phthisic  laryngeo,  oil  ellc  etait  trcsdevcloppee.  Je  fis  dcs  rechcrches  sur  le  l.irynx 
d'.-i.utres  individus,  et  je  trouvai  que  cette  disposition  etait  constanle.  Je  ne  savais  pas 
alors  que  Morgagni  avail  indiqne  el  tail  rcpreRcnter  la  m6mc  disposition."  Cruvcilhier 
compares  its  form  very  aptly  to  a  "  I'lirysrian  casque"  and  Morgagni's  figure,  Advers. 
1,  Episl.  Anat.  .3,  pl.ite  2,  fig.  4,  h;is  the  same  appearance.  But  neither  of  these  anato. 
rnisls  notice  the  follicular  glands  described  by  Mr.  Hilton. 


TRACHEA.  513 

the  superior  laryngeal  is  distributed  principally  to  the  nnucous  mem- 
brane at  the  entrance  of  the  larynx  ;  the  recurrent,  to  the  muscles. 

In  children,  and  in  the  female,  the  larynx  is  less  developed  than 
in  the  adult  male;  the  thyroid  cartilage  forms  a  more  obtuse  angle, 
and  is  less  firm:  in  the  male  the  angle  is  acute,  and  the  cartilages 
often  converted  into  bone. 

THE     TRACHEA. 

The  Trachea  extends  from  opposite  the  fifth  cervical  vertebra  to 
opposite  the  third  dorsal,  where  it  divides  into  the  two  bronchi.  The 
right  bronchus,  larger  than  the  left,  passes  off  nearly  at  right  angles 
to  the  upper  part  of  the  corresponding  lung.  The  left  descends 
obliquely,  and  passes  beneath  the  arch  of  the  aorta,  to  reach  the  left 
lung. 

The  Trachea  is  composed  of — 

Fibro-cartilaginous  rings, 
Fibrous  membrane, 
Mucous  membrane, 
Longitudinal  elastic  fibres, 
Muscular  fibres. 
Glands. 

The  Fibro-cartilaginous  rings  are  from  fifteen  to  twenty  in  num- 
ber, and  extend  for  two-thirds  around  the  cylinder  of  the  trachea. 
They  are  deficient  at  the  posterior  part,  where  the  tube  is  completed 
by  fibrous  membrane.  The  last  ring  has  usually  a  triangular  form 
in  front.  The  rings  are  connected  to  each  other  by  a  membrane 
of  yellow  elastic  fibrous  tissue,  which  in  the  space  between  the  ex- 
tremities of  the  cartilages,  posteriorly,  forms  a  distinct  layer. 

The  Longitudinal  elastic  ftbres  are  situated  immediately  beneath 
the  mucous  membrane  on  the  posterior  part  of  the  trachea,  and 
enclose  the  entire  cylinder  of  the  bronchial  tubes  to  their  ultimate 
terminations. 

The  Muscular  fibres  form  a  thin  layer,  extending  transversely  be- 
tween the  extremities  of  the  cartilages.*  On  the  posterior  surface 
they  are  covered  in  by  a  cellulo-fibrous  lamella,  in  which  are  lodged 
the  tracheal  glands.  These  are  small  flattened  ovoid  bodies,  situated 
in  great  number  between  the  fibrous  and  muscular  layers  of  the 
membranous  portion  of  the  trachea,  and  also  between  the  two  layers 
of  elastic  fibrous  tissue  connecting  the  rings.  They  pour  their 
secretion  upon  the  mucous  membrane. 

Thyroid  Gland. 

The  thyroid  gland  is  one  of  those  organs  which  it  is  found  ex- 
tremely difficult  to  classify  from  the  absence  of  any  positive  know- 
ledge with  regard  to  its  function.     It  is  situated  upon  the  trachea, 

*  I  have  several  times  seen  a  layer  of  longitudinal  muscular  fibres  superadded  to  the 
transverse. — G. 


514  TUVROID  GLAND — LUNGS. 

and  in  an  anatomical  arrangement  should  therefore  be  considered 
in  this  place,  although  bearing  no  part  in  the  function  of  >  respira- 
tion. 

This  gland  consists  of  two  lobes,  which  are  placed  one  on  each 
side  of  the  trachea,  and  are  connected  with  each  other  by  means  of 
an  isthmus,  which  crosses  its  upper  rings.  There  is  considerable 
variety  in  the  situation  and  breadth  of  this  isthmus;  which  should 
be  recollected  in  the  performance  of  operations  upon  the  trachea. 
In  structure  it  appears  to  be  composed  of  a  dense  cellular  paren- 
chyma, enclosing  a  great  number  of  vessels.  The  gland  is  larger 
in  young  subjects  and  in  females,  than  in  the  adult  and  males.  It 
is  the  seat  of  an  enlargement  called  bronchocele,  goitre,  or  the  Der- 
byshire neck. 

A  muscle  is  occasionally  found  connected  with  its  upper  border 
or  with  its  isthmus;  and  attached,  superiorly,  to  the  body  of  the  os 
hyoides,  or  to  the  thyroid  cartilage.  It  was  named  by  Soemmering 
the  "  levator  glandules  thyroidecB." 

Vessels  and  Nerves. — It  is  abundantly  supplied  with  blood  by  the 
superior  and  inferior  thyroid  arteries.  Sometimes  an  additional 
artery  is  derived  from  the  arteria  innominata,  and  ascends  upon  the 
front  of  the  trachea  to  be  distributed  to  the  gland.  The  wounding 
of  this  vessel,  in  tracheotomy,  might  be  fatal  to  the  patient.  The 
nerves  are  derived  from  the  superior  laryngeal  and  sympathetic. 

THE    LUNGS. 

The  lungs  are  two  conical  organs,  situated  one  on  each  side  of 
the  chest,  embracing  the  heart,  and  separated  from  each  other  by  a 
membranous  partition,  the  mediastinum.  On  the  external  or  thoracic 
side  they  are  convex,  and  correspond  with  the  form  of  the  cavity 
of  the  chest;  internally  they  are  concave,  to  receive  the  convexity 
of  the  heart.  Superiorly  they  terminate  in  a  tapering  cone  which 
extends  above  the  level  of  the  first  rib,  and  inferiorly  they  are  broad 
and  concave,  and  rest  upon  the  convex  surface  of  the  diaphragm. 
Their  posterior  border  is  rounded  and  broad,  the  anterior  sharp  and 
marked  by  one  or  two  deep  fissures,  and  the  inferior  which  sur- 
rounds the  base  is  also  sharp. 

The  colour  of  the  lungs  is  pinkish  gray,  mottled,  and  variously 
marked  with  black.  The  surface  is  figured  with  irregularly  poly- 
gonal outlines  which  represent  the  lobules  of  the  organ,  and  the 
area  of  each  of  these  polygonal  spaces  is  crossed  by  lighter  lines. 

Each  lung  is  divided  into  two  lobes  by  a  long  and  deep  fissure, 
which  extends  from  the  posterior  surface  of  the  upper  part  of  the 
organ,  downwards  and  forwards  to  near  the  anterior  angle  of  its 
base. 

In  the  right  lung  the  upper  lobe  is  subdivided  by  a  second  fissure, 
which  extends  obliquely  forwards  from  the  middle  of  the  preceding 
to  the  anterior  border  of  the  organ,  and  marks  oil'  a  small  triangu- 
lar lobe. 

The  Right  lung  is  larger  than  the  left,  in  consequence  of  the  in- 


STRUCTURE  OF  LUNG. 


515 


clination  of  the  heart  to  the  left  side.  It  is  also  shorter,  from  the 
great  convexity  of  the  liver,  which  presses  the  diaphragm  upwards 
upon  the  right  side  of  the  chest  considerably  above  the  level  of  the 
left.     It  has  three  lobes. 


Fig.  177. 


The  left  lung  is  smaller,  has  but  two  lobes,  but  is  longer  than  the 
right. 

Each  lung  is  retained  in  its  place  by  its  root,  which  is  formed  by 
the  pulmonary  artery,  pulmonary  veins  and  bronchial  tubes,  toge- 
ther with  the  bronchial  vessels  and  pulmonary  plexuses  of  nerves. 
The  large  vessels  of  the  root  of  each  lung  are  arranged  in  a  similar 
order  from  before,  backwards,  on  both  sides,  viz. 

Pulmonary  veins. 
Pulmonary  artery. 
Bronchus. 

From  above,  downwards,  on  the  right  side  this  order  is  exactly 
reversed  ;  but  on  the  left  side  the  bronchus  has  to  stoop  beneath  the 

Fig.  177.  Anatomy  of  the  heart  and  lungfs.  1.  The  right  ventricle  ;  the  vessels  to 
the  right  of  the  figure  are  the  middle  coronary  artery  and  veins  ;  and  (hose  to  its  left, 
the  anterior  coronary  artery  and  veins.  2.  The  left  ventricle.  3.  The  right  auricle. 
4.  The  left  auricle.  5.  The  pulmonary  artery.  6,  6.  The  riwht  pulmonary  artery. 
7.  The  left  pulmonary  artery.  8.  The  remains  of  the  ductus  arteriosus.  9.  The  arch 
of  the  aorta.  10.  The  superior  vena  cava.  11.  The  right  vena  innominata,  and  the 
arteria  innominata.  12.  The  right  subclavian  artery  and  vein.  13.  The  right  com- 
mon  carotid  artery  and  vein.  14.  The  left  vena  innominata.  15.  The  left  carotid 
artery  and  vein.  16.  The  left  subclavian  artery  nnd  vein.  17.  The  trachea.  18.  The 
right  bronchus.  19.  The  left  bronchus.  20,20.  The  pulmonary  veins  ;  18,  6,  20,  form 
the  root  of  the  right  lung;  and  7,  19,  20,  the  root  of  the  left.  21.  The  superior  lobe  of 
the  right  lung.  22.  Its  middle  lobe.  23.  Its  inferior  lobe.  24.  The  superior  lobe  of 
the  left  lung.     25.  Its  inferior  lobe. 


516  ROOT  OF  LUNG. 

arch  of  the  aorta,  which  ahers  its  position  to  the  vessels.     They  are 
thus  disposed  on  the  two  sides : 

Right.  Left. 

Bronchus,  Artery, 

Artery,  Bronchus, 

Veins.  Veins. 

Structure. — The  lungs  are  composed  of  the  ramifications  of  the 
bronchial  tubes  which  terminate  in  bronchial  cells  (air  cells),  of  the 
ramifications  of  the  pulmonary  artery  and  veins,  bronchial  arteries 
and  veins,  lymphatics  and  nerves;  the  whole  of  these  structures 
being  held  together  by  cellular  tissue,  which  constitutes  the  paren- 
chyma. The  parenchyma  of  the  hmgs,  when  examined  on  the  sur- 
face or  by  means  of  a  section,  is  seen  to  consist  of  small  polygonal 
divisions,  or  lobules,  which  are  connected  to  each  other  by  an  in- 
terlobular cellular  tissue.  These  lobules  again  consist  of  smaller 
lobules,  and  the  latter  are  formed  by  a  cluster  of  air  cells,  in  the 
parietes  of  Vv'hich  the  capillaries  of  the  pulmonary  artery  and  pul- 
monary veins  are  distributed.* 

Bronchial  tubes. — The  two  bronchi  proceed  from  the  bifurcation 
of  the  trachea  to  their  corresponding  lungs.  The  right  takes  its 
course  nearly  at  ri^ht  angles  with  the  trachea,  and  enters  the  upper 
part  of  the  right  lung,  while  the  left,  longer  and  smaller  than  the 
right,  passes  obliquely  beneath  the  arch  of  the  aorta,  and  enters  the 
lung  at  about  the  middle  of  its  root.  Upon  entering  the  lungs  they 
divide  into  two  branches,  and  each  of  these  divides  and  subdivides 
dichotomously  to  their  ultimate  termination  in  small  dilated  sacs, 
the  bronchial  or  pulmonary  cells. 

The  fibro-cartilaginous  rings  which  are  observed  in  the  trachea 
become  incomplete  and  irregular  in  shape  in  the  bronchi,  and  in  the 
smaller  bronchial  tubes  are  lost  altogether.  At  the  termination  of 
these  tubes  the  fibrous  and  muscular  coats  become  extremely  thin, 
and  are  probably  continued  upon  the  lining  mucous  membrane  of 
the  air  cells. 

The  Pulmonarij  artery,  conveying  the  dark  and  impure  venous 
blood  to  the  lungs,  terminates  in  capillary  vessels,  which  form  a 
minute  network  upon  the  parietes  of  the  bronchial  cells,  and  then 
converge  to  form  the  pulmonary  veins,  by  which  the  arterial  blood, 
purified  in  its  passage  through  the  capillaries,  is  returned  to  the  left 
auricle  of  the  heart. 

The  Bronchial  arierhis,  branches  of  the  thoracic  aorta,  ramify 
upon  the  bronchial  tubes  and  in  the  tissue  of  the  lungs,  and  supply 
them  with  nutrition,  while  the  venous  blood  is  returned  by  the 
bronchial  veins  to  the  vena  azygos. 

The  Lymphatics,  commencing  upon  the  surface  and  in  the  sub- 

*  The  walls  of  the  air  colls  nro  so  imperfect  that  all  the  colls  of  any  lohnlc  commu- 
nicate freely  with  each  otiior,  whilst  llie  cont.ijrurtus  loi)iilcs  are  separated  by  the  paren- 
chyma.  Dr.  Horner's  dissections  cxiiibit  this  in  a  bej-titiful  manner.  Sec  Horner's 
Special  Anatomy,  3d  editiSn. — G. 


PLEURjE MEDIASTINUM.  517 

stance  of  the  lungs,  terminate  in  the  bronchial  glands.  These 
glands,  very  numerous  and  often  of  large  size,  are  placed  at  the 
roots  of  the  lungs,  around  the  bronchi,  and  at  the  bifurcation  of  the 
trachea.  In  early  life  they  resemble  lymphatic  glands  in  other 
situations;  but  in  old  age,  and  often  in  the  adult,  they  are  quite 
black,  and  filled  with  carbonaceous  matter,  and  occasionally  with 
calcareous  deposits. 

The  JVerves  are  derived  from  the  pneumogastric  and  sympathe- 
tic. They  form  two  plexuses, — anterior  pulmonary  plexus,  situated 
upon  the  front  of  the  root  of  the  lungs,  and  composed  chiefly  of 
filaments  from  the  great  cardiac  plexus ;  and  posterior  pulmonary 
plexus  on  the  posterior  aspect  of  the  root  of  the  lungs,  composed 
principally  of  branches  from  the  pneumogastric.  The  branches 
from  these  plexuses  follow  the  course  of  the  bronchial  tubes,  and 
are  distributed  to  the  bronchial  cells. 

PLEURiE. 

Each  lung  is  enclosed,  and  its  structure  maintained,  by  a  serous 
membrane — the  pleura,  which  invests  it  as  far  as  the  root,  and  is 
thence  reflected  upon  the  parietes  of  the  chest.  That  portion  of  the 
membrane  which  is  in  relation  with  the  lung  is  called  pleura  puJmo- 
nalis,  and  that  in  contact  with  the  parietes,  pleura  costalis.  The 
reflected  portion,  besides  forming  the  internal  lining  to  the  ribs  and 
intercostal  muscles,  also  covers  the  diaphragm  and  the  thoracic 
surface  of  the  vessels  at  the  root  of  the  neck. 

The  pleura  must  be  dissected  from  off  the  root  of  the  lung,  to 
see  the  vessels  by  which  it  is  formed  and  the  pulmonary  plexuses. 

MEDIASTINUM. 

The  approximation  of  the  two  reflected  pleurae  in  the  middle  line 
of  the  thorax  forms  a  septum  which  divides  the  chest  into  the  two 
pulmonary  cavities.  This  is  the  mediastinum.  The  two  pleurae 
are  not,  however,  in  contact  with  each  other  at  the  middle  line  in 
the  formation  of  the  mediastinum,  but  leave  a  space  between  them 
which  contains  all  the  viscera  of  the  chest  with  the  exception  of  the 
lungs.  The  mediastinum  is  divided  into  the  anterior,  middle,  and 
postei'ior. 

The  Anterior  mediastinum  is  a  triangular  space,  bounded  in  front 
by  the  sternum,  and  on  each  side  by  the  pleura.  It  contains  a 
quantity  of  loose  cellular  tissue,  in  which  are  found  some  lymphatic 
glands  and  vessels  passing  upwards  from  the  liver;  the  remains  of 
the  thymus  gland,  the  origins  of  the  sterno-hyoid,  sterno-thyroid, 
and  triangularis  sterni  muscles,  and  the  internal  mammary  vessels 
of  the  left  side. 

The  Middle  mediastinum  contains  the  heart  enclosed  in  its  peri- 
cardium; the  ascending  aorta;  the  superior  vena  cava ;  the  bifur- 
cation of  the  trachea ;  the  pulmonary  arteries  and  veins ;  and  the 
phrenic  nerves. 

The  Posterior  mediastinum  is  bounded  behind  by  the  vertebral 

44 


518  PERITONEUM REFLECTIONS. 

coUimn,  in  front  by  the  pericardiunn,  and  on  each  side  by  the 
pleura.  It  contains  the  descending  aorta;  the  greater  and  lesser 
azygos  veins,  and  superior  intercostal  vein;  the  thoracic  duct;  the 
oesophagus  and  pneumogastric  nerves;  and  the  great  splanchnic 
nerves. 

ABDOMEN. 

The  abdomen  is  the  inferior  cavity  of  the  trunk  of  the  body;  it 
is  hounded  in  front  and  at  the  sides  by  the  lower  ribs  and  abdominal 
muscles;  behind,  by  the  vertebral  column  and  abdominal  muscles; 
above,  by  the  diaphragm;  and,  behno,  by  the  pelvis:  and  contains 
the  alimentary  canal,  the  organs  subservient  to  digestion,  viz.  the 
liver,  pancreas,  and  spleen,  and  the  organs  of  excretion,  the  kid- 
neys, with  the  supra-renal  capsules. 

Regions. — For  convenience  of  description  of  the  viscera,  and  for 
reference  to  the  morbid  affections  of  this  cavity,  the  abdomen  is 
divided  into  certain  districts  or  regions.  Thus,  if  two  transverse 
lines  be  carried  around  the  body,  the  one  parallel  with  the  convexi- 
ties of  the  ribs,  the  other  wiih  the  highest  points  of  the  crests  of  the 
ilia,  the  abdomen  will  be  divided  into  three  zones.  Again,  if  a  per- 
pendicular line  be  drawn  at  each  side,  from  the  cartilage  of  the 
eighth  rib  to  the  middle  of  Poupart's  ligament,  the  three  primary 
zones  will  each  be  subdivided  into  three  compartments  or  regions, 
a  middle  and  two  lateral. 

The  middle  region  of  the  upper  zone  being  immediately  over  the 
small  end  of  the  stomach,  is  called  epigastric  {sirl — ya.(fTrj^,  over  the 
stomach).  The  two  lateral  regions  being  under  the  cartilages  of 
the  ribs  are  called  hypochondriac  (l/to — -xovS^oi,  under  the  cartilages). 
The  middle  region  of  the  middle  zone  is  the  umbilical;  the  two 
lateral,  the  lumbar.  The  middle  region  of  the  inferior  zone  is  the 
hypogastric  {^'^o — yadrri^,  below  the  stomach) ;  and  the  two  lateral, 
the  iliac.  In  addition  to  these  divisions,  we  constantly  use  the  term 
inguinal  region,  in  reference  to  the  vicinity  of  Poupart's  ligament. 

Position  of  the  Viscera. — In  the  upper  zone  will  be  seen  the  liver, 
extending  across  from  the  right  to  the  left  side ;  the  stomach  and 
spleen  on  the  left,  and  the  pancreas  and  duodenum  behind.  In  the 
middle  zone  is  the  transverse  portion  of  the  colon,  with  the  upper 
part  of  the  ascending  and  descending  colon,  omentum,  small  intes- 
tines, mesentery,  and,  behind,  the  kidneys  and  supra-renal  capsules. 
In  the  inferior  zone  is  the  lower  part  of  the  omentum  and  small  in- 
^testines,  the  caecum,  ascending  and  descending  colon  with  the  sig- 
moid flexure,  and  ureters. 

The  smooth  and  polished  surface  which  the  viscera  and  parietes 
of  the  abdomen  present,  is  due  to  the  peritoneum  which  should  in 
the  next  place  be  studied. 

P  E  R  I  T  O  N  R  U  M. 

The  Peritoneum  (nrs^irslvsiv  to  extend  around)  is  a  serous  mem- 
brane, and  therefore  a  shut  sac:  a  single  exception  exists  in  the 


PERITONEUM — DUPLICATURES. 


519 


human  subject  to  this  character,  viz.  in  the  female,  where  the  peri- 
toneum is  perforated  by  the  open  extremities  of  the  Fallopian  tubes, 
and  is  continuous  with  their  mucous  lining. 

The  simplest  idea  that  can  be  given  of  a  serous  membrane,  which 
may  apply  equally  to  all,  is,  that  it  invests  the  viscus  or  viscera, 
and  is  then  reflected  upon  the  parietes  of  the  containing  cavity.  If 
the  cavity  contain  only  a  single  viscus,  the  consideration  of  the 
serous  membrane  is  extremely 
simple.     But    in   the   abdomen,  ^^S- 1'''^- 

where  there  are  a  number  of 
viscera,  the  serous  membrane 
passes  from  one  to  the  other 
until  it  has  invested  the  whole, 
before  it  is  reflected  on  the  pari- 
etes. Hence  its  reflections  are 
a  little  more  complicated. 

In  tracing  the  reflections  of 
the  peritoneum  in  the  middle 
line,  we  commence  with  the 
diaphragm,  which  is  lined  by 
two  layers,  one  from  the  pari- 
etes in  front,  anterior,  and  one 
from  the  parietes  behind,  poste- 
rior. These  two  layers  of  the 
same  membrane,  at  the  posterior 
part  of  the  diaphragm,  descend 
to  the  upper  surface  of  the  liver, 
forming  the  coronary  and  lateral 
ligaments  of  the  liver.  They 
then  surround  the  livei%  one 
going  in  front,  the  other  behind 
that  viscus,  and,  meeting  at  its 
under  surface,  pass  to  the  sto- 
mach, forming  the  lesser  omen- 
tum. They  then,  in  the  same 
manner,  surround  the  stomach, 

Fig.  178.  The  reflections  of  tlie  peritoneum.  D.  Tlie  diaphragm.  L.  The  liver.  S. 
The  stomach.  C.  The  transverse  colon.  D.  The  transverse  duodenum.  P.  The  pan- 
creas.  I.  The  small  intestines.  R.  Tlie  rectum.  B.  The  urinary  bladder.  1.  The 
anterior  layer  of  the  peritoneum,  lining  the  under  surface  of  the  diaphragm.  2.  The 
posterior  layer.  3.  Tlie  two  layers  passing  to  the  posterior  border  of  the  liver,  and 
forming  the  coronary  ligament.  4.  The  lesser  omentum  :  the  two  layers  passing  from 
the  under  surface  of  the  liver  to  the  lesser  curve  of  the  stomach.  5.  The  iwo  layers 
meeting  at  the  greater  curve,  then  passing  downwards  and  returning  upon  themselves, 
forming  (6)  the  greater  omentum.  7.  The  transverse  mesocolon.  8.  The  posterior 
layer  traced  upwards  in  front  of  D,  the  transverse  duodenum,  and  P,  the  pancreas,  to 
become  continuous  with  the  posterior  layer  (2).  9.  The  foramen  of  Winslow  ;  the 
dotted  line  bounding  this  foramen  inferiorly,  marks  the  course  of  the  hep;itic  artery 
tnrwards,  to  enter  between  the  layers  of  the  lesser  omentum.  10.  The  mesentery  en- 
circling  the  small  intestine.  II.  The  recto-vesical  f  ild,  formed  by  the  descending  an- 
terior layer.  I'i.  The  anterior  layer  traced  upwards  upon  the  internal  surface  of  the 
abdominal  parietes  to  the  layer  (I),  with  wliich  the  examination  commenced. 


520  PERITOUEUM DUPLICATURES. 

and  meeting  at  its  lower  border  descend  for  some  distance  in  front 
of  the  intestines,  and  return  to  the  transverse  colon,  forming  the 
great  omentum ;  they  then  surround  the  transverse  colon,  and  pass 
directly  backwards  to  the  vertebral  column,  forming  the  transverse 
meso-cohn.  Here  the  two  layers  separate  ;  the  posterior  ascends  in 
front  of  the  pancreas  and  aorta,  and  returns  to  the  posterior  part  of 
the  diaphragm,  where  it  forms  the  posterior  layer,  with  which  we 
commenced.  The  anterior  descends,  invests  all  the  small  intestines, 
and  returning  to  the  vertebral  column  forms  the  mesentery.  It  then 
descends  into  the  pelvis  in  front  of  the  rectum,  which  it  holds  in  its 
place  by  means  of  a  fold  called  meso-rectum,  forms  a  pouch,  the 
recto-vesical  fold,  between  it  and  the  bladder,  ascends  upon  the  pos- 
terior surface  of  the  bladder,  forming  its  false  ligaments,  and  re- 
turns upon  the  anterior  parietes  of  the  abdomen  to  the  diaphragm, 
whence  we  first  traced  it. 

In  the  female,  after  descending  into  the  pelvis  in  front  of  the 
rectum,  it  is  reflected  upon  the  posterior  surface  of  the  vagina  and 
uterus.  It  then  descends  on  the  anterior  surface  of  the  uterus,  and 
forms  at  either  side  the  broad  ligaments  of  that  organ.  From  the 
uterus  it  ascends  upon  the  posterior  surface  of  the  bladder  and  ante- 
rior parietes  of  the  abdomen,  and  is  continued,  as  in  the  male,  to 
the  diaphragm. 

In  this  way  the  continuity  of  the  peritoneum,  as  a  whole,  is  dis- 
tinctly shown,  and  it  matters  not  where  the  examination  commence 
or  where  it  terminate,  still  the  same  continuity  of  surface  will  be 
discernible  throughout.  If  we  trace  it  from  side  to  side  of  the 
abdomen,  we  may  commence  at  the  umbilicus ;  we  then  follow  it 
outwards  lining  the  inner  side  of  the  parietes  to  the  ascending  colon ; 
it  surrounds  that  intestine  ;  it  then  surrounds  the  small  intestine, 
and  returning  on  itself  forms  the  mesentery.  It  then  invests  the 
descending  colon,  and  reaches  the  parietes  on  the  opposite  side  of 
the  abdomen,  whence  it  may  be  traced  to  the  exact  point  from 
which  we  started. 

The  viscera,  which  are  thus  shown  to  be  invested  by  the  perito- 
neum in  its  course  downwards,  are  the — 

Liver, 
Stomach, 
Transverse  colon, 
Small  intestines. 
Pelvic  viscera. 

The  folds,  formed  between  these  and  between  the  diaphragm  and 
the  liver,  are 

(Diaphragm.) 

Broad,  coronary,  and  lateral  ligaments. 

(Liver.) 

Lesser  omentum. 


PERITONEUM OMENTA.  521 

(Stomach.) 

Greater  omentum. 

(Transverse  colon.) 

Transverse  meso-colon, 
Mesentery, 
Meso-recium, 
Recto-vesical  fold, 

False  ligaments  of  the  bladder. 
And  in  the  female,  the 

Broad  ligaments  of  the  uterus. 

The  ligaments  of  the  liver  will  be  examined  with  that  organ. 

The  Lesser  omentum  is  the  duplica'ure  passing  between  the  liver 
and  the  upper  border  of  the  stomach.  It  is  extremely  thin,  except- 
ing at  its  right  border,  where  it  is  free,  and  contains  between  its 
layers,  the 

Hepatic  artery. 

Ductus  communis  choledochus, 

Portal  vein, 

Hepatic  plexus  of  nerves. 

Lymphatics. 

These  structures  are  enclosed  in  a  loose  cellular  tissue,  called 
Glisson^s  capsu/e*  The  relative  position  of  the  three  vessels  is, — 
the  a/tery  to  the  left,  the  duct  to  the  right,  and  the  vein  between  and 
behind. 

If  the  finger  be  introduced  behind  this  right  border  of  the  lesser 
omentum,  it  will  be  situated  in  an  opening  called  the  foramen  of 
Winslow.]  In  front  of  the  finger  will  lie  the  right  border  of  the 
lesser  omentum  ;  behind  it  the  diaphragm,  covered  by  the  ascend- 
ing or  posterior  layer  of  the  peritoneum;  below,  the  hepatic  artery, 
curving  forwards  from  the  coeliac  axis ;  and  above,  the  lobus 
Spigelii.  These,  therefore,  are  the  boundaries  of  the  foramen  of 
Winslow,  which  is  nothing  more  than  a  constriction  of  the  general 
cavity  of  the  peritoneum  at  this  point,  arising  out  of  the  necessity 
for  the  hepatic  and  gastric  arteries  to  pass  forwards  from  the 
ccEliac  axis  to  reach  their  respective  viscera. 

If  air  be  blown  through  the  foramen  of  Winslow,  it  will  descend 
behind  the  lesser  omentum  and  stomach  to  the  space  between  the 
descending  and  ascending  pair  of  layers,  forming  the  great  omen- 
tum.    This  is  sometimes  called  the  lesser  cavity  of  the  peritoneum, 

*  Francis  Glisson,  Professor  of  Medicine  in  the  University  of  Cambridge.  His 
work,  "  De  Anatomia  Hep;itis,"  was  published  in  1654. 

t  Jacob  Beniunus  Winslow  :  his  "  Exposition  Anatomique  de  la  Structure  du  Corps 
Humain,"  was  publislied  in  Paris  in  173i. 

44* 


522  OMENTA MESENTEET. 

and  that  external  to  the  foramen  the  greater  cavity ;  in  which  case 
the  foramen  is  considered  as  the  means  of  communication  between 
the  two.  There  is  a  great  objection  to  this  division,  as  it  might 
lead  the  inexperienced  to  believe  that  there  were  really  two  cavi- 
ties. There  is  but  one  only,  the  foramen  of  Winslow  being  merely 
a  constriction  of  that  one,  to  facilitate  the  communication  betvi^een 
the  nutrient  arteries  and  the  viscera  of  the  upper  part  of  the 
abdomen. 

The  Great  omentum  consists  of  four  layers  of  peritoneum,  the  two 
which  descend  from  the  stomach,  and  the  same  two,  returning 
upon  themselves  to  the  transverse  colon.  A  quantity  of  adipose 
substance  is  deposited  around  the  vessels  which  ramify  through  its 
structure.  It  would  appear  to  perform  a  double  function  in  the 
economy.  1st,  Protecting  the  intestines  from  cold,  and,  2dly, 
Facilitating  the  movement  of  the  intestines  upon  each  other  during 
their  vermicular  action. 

The  Transverse  meso-colon  (m-sVoj,  middle,  being  attached  to  the 
middle  of  the  cylinder  of  the  intestine)  is  the  medium  of  connexion 
between  the  transverse  colon  and  the  posterior  wall  of  the  abdomen. 
It  also  affords  to  the  nutrient  arteries  a  passage  to  reach  the  intes- 
tine ;  and  encloses  between  its  layers,  at  the  posterior  part,  the 
transverse  portion  of  the  duodenum. 

The  Mesentery  (p-stfov  svrs^ov,  being  connected  to  the  middle  of  the 
cylinder  of  the  small  intestine)  is  the  medium  of  connexion  between 
the  small  intestines  and  the  posterior  wall  of  the  abdomen.  It  is 
oblique  in  its  direction,  being  attached  to  the  posterior  wall,  from 
the  left  side  of  the  second  lumbar  vertebra  to  the  right  iliac  fossa. 
It  retains  the  small  intestines  in  their  places,  and  gives  passage  to 
the  mesenteric  arteries,  veins,  nerves,  and  lymphatics. 

The  Meso-rectum,  in  like  manner,  retains  the  rectum  in  connexion 
with  the  front  of  the  sacrum.  Besides  this,  there  are  some  minor 
folds  in  the  pelvis,  as  the  recto-vesical  fold,  the  false  ligaments  of  the 
bladder,  and  broad  ligaments  of  the  uterus. 

The  Appendices  epiploiccB  are  small  irregular  pouches  of  peri- 
toneum, filled  with  fat,  and  situated  like  fringes  upon  the  large 
intestine. 

Three  other  duplicatures  of  peritoneum  are  situated  in  the  sides 
of  the  abdomen  ;  they  are  the  gastro-phrenic  ligament ;  the  gastro- 
splenic  omentum,  the  ascending  and  descending  meso-colon.  The 
gastro-phrenic  ligament  is  a  small  duplicature  of  the  peritoneum, 
which  descends  from  the  diaphragm  to  the  extremity  of  the  oeso- 
phagus, and  to  the  lesser  curve  of  the  stomach.  The  g astro-splenic 
omentum  is  the  duplicature  which  connects  the  spleen  to  the  sto- 
mach. The  ascending  meso-colon  is  the  fold  which  connects  the 
upper  part  of  the  ascending  colon  with  the  posterior  wall  of  the 
abdomen ;  and  the  descending  meso-colon,  that  which  retains  the 
sigmoid  flexure  in  connexion  with  the  abdominal  wall. 

Structure  of  serous  mem,brane. — Serous  membrane  consists  of  two 
layers,  an  external  or  cellular  layer,  and  an  internal  layer  or  epithe- 


ALIMENTARY  CANAL.  523 

lium.  The  cellular  layer  upon  its  outer  surface  is  rough  and  vascu- 
lar, and  adherent  to  surrounding  structures;  but  on  its  inner  surface 
is  dense  and  smooth,  and  wholly  deficient  of  vessels  carrying  red 
blood.  The  smooth  and  brilliant  surface  of  serous  membrane  is  due 
to  a  distinct  epithelium,  which  has  been  shown  by  the  excellent  re- 
searches of  Henle,  to  be  composed  of  laminae  of  vesicles,  and  of 
flattened  polygonal  scales  with  central  nuclei,  like  the  epithelium  of 
mucous  membrane.  Dr.  Henle  has  observed  this  structure,  which 
may  be  easily  demonstrated  with  a  good  microscope  upon  the  sur- 
face of  all  the  serous  membranes  of  the  body,  upon  the  surface  of 
the  lining  membrane  of  arteries  and  veins,  and  upon  synovial  mem- 
branes. 

The  general  characters  of  a  serous  membrane  are  its  resemblance 
to  a  shut  sac,  and  its  secretion  of  a  peculiar  fluid,  resembling  the 
serum  of  the  blood;  but  the  former  of  these  characters  is  not  abso- 
lutely essential  to  the  identity  of  a  serous  membrane;  for,  as  we 
have  shown  above,  the  peritoneum  in  the  female  is  perforated  by  the 
extremities  of  the  Fallopian  tubes;  while  in  aquatic  reptiles  there  is 
a  direct  communication  between  its  cavity  and  the  medium  in  which 
they  live. 

From  the  variable  nature  of  the  secretion  of  these  membranes, 
they  have  been  divided  into  two  classes — the  true  serous  membranes, 
viz.  the  arachnoid,  pericardium,  pleurae,  peritoneum,  and  tunicas  va- 
ginales,  which  pour  out  a  secretion  containing  but  a  small  propor- 
tion of  albumen;  and  the  synovial  membranes  and  bursas  which 
secrete  a  fluid  containing  a  larger  quantity  of  albumen. 

ALIMENTARY     CANAL. 

The  Alimentary  canal  is  a  musculo-membranous  tube,  extending 
from  the  mouth  to  the  anus.  It  is  variously  named  in  the  different 
parts  of  its  course;  hence  it  is  divided  into  the 

Mouth, 
Pharynx, 

(Esophagus, 
Stomach. 

(  Duodenum, 
Small  intestine  <  Jejunum, 
(  Ileum. 

(  Cascum, 
Large  intestine  }  Colon, 
(  Rectum. 

The  Mouth  is  the  irregular  cavity  which  contains  the  organs  of 
taste  and  the  principal  instruments  of  tnastication.  It  is  bounded  in 
front  by  the  lips:  on  either  side  by  the  internal  surface  of  the 
cheeks;  above  by  the  hard  palate  and  teeth  of  the  upper  jaw;  below 
by  the  tongue,  by  the  mucous  membrane  stretched  between  the 
arch  of  the  lower  jaw  and  the  under  surface  of  the  tongue,  and  by 


524 


ALIMENTARY  CANAL. 


the  teeth  of  the  hiferior  maxilla;  and  behind  by  the  soft  palate  and 
fauces. 

The  Lips  are  two  fleshy  folds,  formed  externally  by  common  in- 
tegument, and  internally  by  mucous  membrane,  and  containing 
between  these  two  layers  the  muscles  of  the  lips,  a  qunntity  of  fat, 
and  numerous  small  labial  glands.  They  are  attached  to  the  sur- 
face of  the  upper  and  lower  jaw,  and  each  lip  is  connected  to  the 
gum  in  the  middle  line  by  a  fold  of  mucous  membrane,  the  frasnum 
labii  superioris  and  frcenum  labii  inferioris,  the  former  being  the 
larger. 

The  CheeJiS  (buccas)  are  continuous  on  either  hand  with  the  lips, 
and  form  the  sides  of  the  face;  they  are  composed  of  integument, 
a  large  quantity  of  fat,  muscles,  mucous  membrane,  and  buccal 
glands. 

The  mucous  membrane  lining  the  cheeks  is  reflected  above  and 
below  upon  the  sides  of  the  jaws,  and  is  attached  postei  iorly  to  the 
anterior  margin  of  the  ramus  of  the  lower  jaw.  At  about  its  mid- 
dle, opposite  to  the  second  molar  tooth  of  the  upper  jaw,  is  a  piipilla, 
upon  which  may  be  observed  a  small  opening,  the  entrance  of  the 
duct  of  the  parotid  gland. 

The  Hard  palate  is  a  dense  structure,  composed  of  mucous  mem- 
brane, palatal  glands,  fibrous  tissue,  vessels  and  nerves,  and  firmly 
connected  to  the  palate  processes  of  the  superior  maxillary  and 
palate  bones.  It  is  bounded  in  front  and  on  each  side  by  the  alveolar 
processes  and  gums,  and  is  continuous  behind  with  the  soft  palate. 
It  is  marked  along  the  middle  line  by  an  elevated  raphe,  and  pre- 
sents upon  each  side  of  the  raphe  a  number  of  transverse  ridges 
and  grooves.  Near  the  anterior  extremity,  and  immediately  behind 
the  middle  incisor  teeth,  is  a  papilla  which  corresponds  with  the 
termination  of  the  naso-palatine  canal,  and  has  been  supposed  to  be 
endowed  with  a  peculiar  sensibility. 

The  Gums  are  composed  of  a  thick  and  dense  mucous  membrane, 
"which  is  closely  adherent  to  the  periosteum  of  the  alveolar  pro- 
cesses, and  embraces  the  necks  of  the  teeth.  They  are  remarkable 
for  their  hardness  and  insensibility,  and  for  their  close  contact, 
without  adhesion  to  the  surface  of  the  tooth.  From  the  neck  of 
the  tooth  they  are  reflected  into  the  alveolus,  and  become  continuous 
with  the  periosteal  membrane  of  that  cavity. 

The  Tongue  has  been  already  described  as  an  organ  of  sense;  it 
is  invested  by  mucous  membrane,  which  is  reflected  from  its  under 
part  upon  the  inner  surface  of  the  lower  jaw,  and  constitutes,  with 
the  muscles  beneath,  the  floor  of  the  mouth.  Upon  the  under  sur- 
face of  the  tongue,  near  to  its  anterior  part,  the  mucous  membrane 
forms  a  consideraljle  fold,  which  is  called  the  fra^num  Iingua3;  and 
on  each  side  ol"  the  fracnum  is  a  large  papilla,  the  commencement 
of  the  duct  of  the  submaxillary  gland,  and  several  smaller  openings, 
the  ducts  of  the  sublingual  gland. 

The  Sofl  pahdc  (velum  pendulum  palati)  is  a  fold  of  mucous  mem- 
brane situated  at  the  posterior  part  of  the  mouth.     It  is  continuous, 


^  SALIVARY  GLANDS.  525 

superiorly  with  the  hard  palate,  and  is  composed  of  mucous  mem- 
brane, palatal  glands,  and  muscles.  Hanging  from  the  middle  of  its 
inferior  border  is  a  small  rounded  process,  the  uvula ;  and  passing 
outwards  from  the  uvula  on  each  side  are  two  curved  folds  of  the 
mucous  membrane,  the  arches,  or  pillars  of  the  palate.  The  anterior 
pillar  is  continued  downwards  to  the  side  of  the  base  of  the  tongue, 
and  is  formed  by  the  projection  of  the  palato-glossus  muscle.  The 
posteiior  jjillar  is  prolonged  downwards  and  backwards  into  the 
pharynx,  and  is  formed  by  the  convexity  of  the  palato-pharyngeus 
muscle.  These  two  pillars,  closely  united  above,  are  separated 
below  by  a  triangular  interval  or  niche,  in  which  the  tonsil  is 
lodged. 

The  Tonsils  (amygdalae)  are  two  glandular  organs,  shaped  like 
almonds,  and  situated  between  the  anterior  and  posterior  pillar  of 
the  soft  palate,  on  each  side  of  the  fauces.  They  are  cellular  in 
texture,  and  composed  of  an  assemblage  of  mucous  follicles,  which 
open  upon  the  surface  of  the  gland.  Externally  they  are  invested 
by  the  pharyngeal  fascia,  which  separates  them  from  the  superior 
constrictor  muscle  and  internal  carotid  artery,  and  prevents  an  ab- 
scess from  opening  in  that  direction.  In  relation  to  surrounding 
parts,  they  correspond  with  the  angle  of  the  lower  jaw. 

The  space  included  between  the  soft  palate  and  the  root  of  the 
tongue  is  the  isthmus  of  the  fauces.  It  is  bounded  above  by  the  soft 
palate ;  on  each  side  by  the  pillars  of  the  soft  palate  and  tonsils ; 
and  beloiv  by  the  root  of  the  tongue.  It  is  the  opening  between  the 
mouth  and  pharynx. 

SALIVARY    GLANDS. 

Communicating  with  the  mouth  are  the  excretory  ducts  of  three 
pairs  of  salivary  glands,  the  parotid,  submaxillary,  and  sublingual. 

The  Parotid  gla.nd  (-Tra^a,  near,  ouj,  wto?,  the  ear),  the  largest  of 
the  three,  is  situated  immediately  in  front  of  the  external  ear,  and 
extends  superficially  for  a  short  distance  over  the  masseter  muscle, 
and  deeply  behind  the  ramus  of  the  lower  jaw.  It  reaches  infe- 
riorly  to  below  the  level  of  the  angle  of  the  lower  jaw,  and  poste- 
riorly to  the  mastoid  process,  slightly  overlapping  the  insertion  of 
the  sterno-mastoid  muscle.  Embedded  in  its  substance  are  the 
external  carotid  artery,  temporo-maxillary  vein,  and  facial  nerve  ; 
and,  emerging  from  its  anterior  border,  the  transverse  facial  artery 
and  branches  of  the  pes  anserinus  ;  and  above,  the  temporal  artery. 

The  duct  of  the  parotid  gland  (vStenon's*  duct)  commences  at  the 
papilla  upon  the  internal  surface  of  the  cheek,  opposite  the  second 
molar  tooth  of  the  upper  jaw  ;  and,  piercing  the  buccinator  muscle, 
crosses  the  masseter  to  the  anterior  border  of  the  gland,  where  it 
divides  into  several  branches,  which  subdivide  and  ramify  through 

*  Nicholas  Stenon,  an  anatomist  of  great  research.  He  discovered  the  parotid  duct 
while  in  Paris.  He  was  appointed  professor  of  medicine  in  Copenhagen  in  1672.  His 
work,  "  De  Musculis  et  Glandulis  Observationes,"  was  published  in  1664. 


5:26  THE  SALIVARY  GLAXDS. 

its  structure,  to  terminate  in  the  smnll  ca3cal  pouches  of  which  the 
gland  is  composed.  A  small  branch  is  generalk  given  off  from  the 
duct  while  crossing  the  masseter  muscle,  which  fcjrms,  by  its  rami- 
fications and  terminal  dilatations,  a  small  glandular  appendage,  the 
socia  parotidis.  Stenon's  duct  is  remarkably  dense  and  of  con- 
siderable thickness,  while  the  area  of  its  canal  is  extremely  small. 

The  SuhmuxUIary  gland  is  situated  in  the  posterior  angle  of  the 
submaxillary  triangle  of  the  neck.  It  rests  upon  the  hyo-glossus 
and  mylo-hyoideus  muscles,  and  is  covered  in  by  the  body  of  the 
lower  jaw  and  by  the  deep  cervical  fascia.  It  is  separated  from 
the  parotid  gland  by  the  stylo-maxillary  ligament,  and  from  the 
sublingual  by  the  mylo-hyoideus  muscle.  Embedded  among  its 
lobules  is  the  facial  artery  and  the  submaxillary  ganglion. 

The  Excrptory  duct  (Wharton's)  of  the  submaxillary  gland  com- 
menc^es  upon  the  papilla,  by  the  side  of  the  frcenum  linguas,  and 
passes  backwards  beneath  the  mylo-hyoideus  and  resting  upon  the 
hyo-glossus  muscle,  to  the  middle  of  the  gland,  where  it  divides  inio 
numerous  branches,  which  ramify  through  the  structure  of  the  gland 
to  its  csecal  terminations.  It  lies  in  its  course  against  the  mucous 
membrane  forming  the  floor  of  the  mouth,  and  causes  a  projecting 
ridge  upon  its  surface. 

The  Sublingual  is  an  elongated  and  flattened  gland,  situated  be- 
neath the  mucous  membrane  of  the  floor  of  the  mouth,  on  each 
side  of  the  frrenum  linguas.  It  is  in  relation  abore  with  the  mucous 
membrane;  in  front  with  the  depression  by  the  side  of  the  symphy- 
sis of  the  lower  jaw  ;  externally  whh  the  mylo-hyoideus  muscle; 
and  internally  with  the  lingual  nerve  and  genio-hyo-glossus  muscle. 

It  pours  its  secretion  into  the  mouih  by  seven  or  eight  small  ducts, 
which  commence  by  small  openings  on  each  side  of  the  frsenum 
linguas. 

Structure. — The  salivary  are  conglomerate  glands,  consisting  of 
lobes,  which  arc  made  up  of  angular  lobules,  and  these  of  still 
smaller  lobules. 

The  smallest  lobule  is  apparently  composed  of  granules,  which 
are  minute  cajcal  pouches,  formed  by  the  dilatation  of  the  extreme 
ramifications  of  the  ducts.  These  minute  ducts  unite  to  form  lobu- 
lar ducts,  and  the  lobular  ducts  constitute  by  iheir  union  a  single 
excretory  duct. 

The  csecal  pouches  are  connected  by  cellular  tissue,  so  as  to 
form  a  minute  lobule;  the  lobules  are  held  together  by  a  more  con- 
densed cellular  layer ;  and  the  larger  lobes  are  enveloped  by  a  dense 
cellulo-fibrous  capsule,  which  is  firmly  attached  to  the  deep  cervical 
fascia. 

Vessels  and  JVerves. — The  parotid  gland  is  abundantly  supplied 
with  arteries  by  the  external  carotid  ;  the  submaxillary  by  the 
facial;  and  the  sublingual  by  the  sublingual  branch  of  ihe  lingual 
artery. 

The  JVeroes  of  the  parotid  gland  are  derived  from  the  auricular 
branch  of  the  inferior  maxillary  nerve,  from  the  auricularis  mag- 


•PHARYNX ITS  OPENINGS. 


527 


Fiff.  179. 


nus,  and  from  the  nervi  molles  of  the  external  carotid  artery.  The 
submaxillary  aland  is  supplied  by  the  branches  of  the  submaxillary 
ganglion,  and  "by  filaments  from'the  mylo-hyoidean  nerve;  and  the 
sublingual  by  filaments  from  the  submaxillary  ganglion  and  gusta- 
tory nerve. 

PHARYNX. 

The  pharynx  ((pa^u/l,  the  throat)  is  a  musculo-membranous  sac, 
situated  upon  the  cervical  portion  of  the  vertebral  column,  and 
extending  from  the  base  of  the  skull  to  a  point  corresponding  with 
the  cricoid  cartilage  in  front,  and  the  fifth  cervical  vertebra  behind. 
It  is  composed  of  mucous  membrane,  muscles,  vessels,  and  nerves, 
and  is  invested  by  a  strong  fascia,  situated 
between  the  mucous  membrane  and  mus- 
cles, which  serves  to  connect  it  with  the 
basilar  process  of  the  occipital  bone  and 
with  the  petrous  portions  of  the  temporal 
bones.  Upon  its  anterior  part  it  is  incom- 
plete, and  has  opening  into  it  seven  fora- 
mina, viz. 

Posterior  nares,  two, 

Eustachian  tubes,  two, 

Mouth, 

Larynx, 

CEsophagus- 

The  Posterior  nares  are  the  two  large 
openings  at  the  upper  and  front  part  of  the 
phnrynx.  On  each  side  of  these  openings, 
and  slightly  above  the  posterior  termination  of  the  inferior  turbi- 
nated bone,  is  the  irregular  depression  in  the  mucous  membrane, 
marking  the  entrance  of  the  Eustachian  tube.  Beneath  the  poste- 
rior nares  is  the  large  opening  into  the  moulh,  partly  veiled  by  the 
soft  palate;  and,  beneath  the  root  of  the  tongue,  the  opening  of  the 
larynx.  The  cesophageal  opening  is  the  lower  constricted  portion 
of  the  pharynx. 

(Esnphagvs. — The  oesophagus  (oi'siv,  to  bear,  (paystv,  to  eat)  is  a 
slightly  flexuous  canal,  inclining  to  the  left  in  the  neck,  to  the  right 
in  the  upper  part  of  the  thorax,*  and  again  to  the  left  in  its  course 

Fig.  179.  The  pharynx  laid  open  from  behind.  1.  A  section  carried  transversely 
through  tlie  base  of  the  skull.  2,  2.  The  walls  of  the  ph.irynx  drawn  to  each  side. 
3,  3.  The  posterior  nares,  separated  by  the  vomer.  4.  The  extrctnity  of  the  Eusta- 
chian tulie  of  one  side.     5.  Tlie  sotl  palate.     6.  The  posterior  pillar  of  the  soil  palate. 

7.  Us  anterior  pillar;  the  tonsil  is  seen  situated  in  the  niche  Ijetuecn  the  two  pillars. 

8.  The  root  of  the  tongue,  partly  concealed  by  the  uvula.  9.  The  epiglottis,  over- 
hanging (10)  the  opening  of  the  glottis.  11.  The  posterior  part  of  the  larynx-.  1"3  The 
opening  into  the  oesophagus.  13.  The  external  surface  of  the  oesophagus.  14.  Tiie 
trachea. 

*  Cruveilhier  remarks  that  this  inflexion  explains  the  obstruction  which  a  bougie 
sometimes  meets  with  in  its  passage  along  the  oesophagus  opposite  the  first  rib. 


528  STOMACH — DUODENUM. 

through  the  posterior  mediastinum ;  it  commences  at  the  termina- 
tion of  the  pharynx,  opposite  the  lower  border  of  the  cricoid  carti- 
lage and  fifth  cervical  vertebra,  and  descends  the  neck,  behind  and 
rather  to  the  left  of  the  trachea.  It  then  passes  behind  the  arch  of 
the  aorta,  and  along  the  posterior  mediastinum,  lying  in  front  of  the 
thoracic  aorta,  to  the  oesophageal  opening  in  the  diaphragm,  where 
it  enters  the  abdomen,  and  terminates  at  the  cardiac  orifice  of  the 
stomach  at  a  point  about  opposite  to  the  tenth  dorsal  vertebra.  The 
oesophagus  is  flattened  and  narrow  in  the  cervical  region,  and  cylin- 
drical in  the  rest  of  its  course ;  its  largest  diameter  is  met  with  near 
to  the  lower  part  of  its  course. 

THE    STOMACH. 

The  stomach  is  an  expansion  of  the  alimentary  canal,  situated  in 
the  left  hypochondriac,  and  extending  into  the  epigastric  region.  It 
is  directed  somewhat  obliquely  from  above  downwards,  from  left  to 
right  and  from  before  backwards;  and  in  the  female  where  the 
injurious  system  of  tight-lacing  has  been  pursued  is  longer  than  in 
the  male.  On  account  of  the  peculiarity  of  its  form,  it  is  divided 
into  a  greater  or  splenic,  and  a  lesser  or  fyloric,  end ;  a  lesser  cur- 
vature above,  and  a  greater  curvature  below ;  an  anterior  and  a 
posterior  surface ;  a  cardiac  orifice,  and  a  pyloric  orifice.  The  great 
end  is  not  only  of  large  size,  but  expands  beyond  the  point  of 
entrance  of  the  oesophagus,  and  is  embraced  by  the  concave  sur- 
face of  the  spleen.  The  pylorus  is  the  small  and  contracted  extre- 
mity of  the  organ;  near  to  its  extremity  is  a  small  dilatation,  which 
was  called  by  Willis  the  antrum  of  the  pylorus.  The  two  curva- 
tures give  attachment  to  the  peritoneum ;  the  upper  curve  to  the 
lesser  omentum,  and  the  lower  to  the  greater  omentum.  The 
anterior  surface  looks  upwards  and  forwards,  and  is  in  relation 
with  the  diaphragm,  which  separates  it  from  the  viscera  of  the 
thorax  and  from  the  six  lower  ribs,  with  the  left  lobe  of  the  liver, 
and  in  the  epigastric  region,  with  the  abdominal  parietes.  The 
posterior  surface  looks  downwards  and  backwards,  and  is  in  rela- 
tion with  the  diaphragm,  the  pancreas,  the  third  portion  of  the 
duodenum,  the  transverse  meso-colon,  the  right  kidney,  and  supra- 
renal capsule  ;  this  surface  forms  the  anterior  boundary  of  that  cul 
de  sac  of  the  peritoneum  which  is  situated  behind  the  lesser  omen- 
tum and  extends  into  the  greater  omentum. 

Small  Intestines. — The  small  intestine  is  about  twenty-five  feet  in 
length,  and  is  divisible  into  three  portions,  duodenum,  jejunum,  and 
ileum. 

The  Duodenum  (called  5u5zxadaxTvkov  by  Herophilus)  is  somewhat 
larger  than  the  rest  of  the  small  intestines,  and  has  received  its 
name  from  being  about  equal  in  length  to  the  breadth  of  twelve 
fingers.  Commencing  at  the  pylorus,  it  ascends  ohliquehj  back- 
wards to  the  under  surface  of  the  liver  :  it  next  descends  perpendi- 
cularly  m  front  of  the  right  kidney,  and  then  passes  nearly  trans- 
versely across  the  third  lumbar  vertebra  ;  terminating  in  the  jejunum 


THE  DUODENUM. 


629 


on  the  left  side  of  the  second  lumbar  vertebra,  where  it  is  crossed 
by  the  superior  mesenteric  artery  and  portal  vein.  The  first  or 
oblique  portion  of  its  course,  between  two  and  three  inches,  is  com- 
pletely enclosed  by  the  peritoneum :  ii  is  in  relation,  above  with  the 
liver  and  neck  of  the  gall-bladder ;  in  front  with  the  greater 
omentum  and  abdominal  parietes ;  and  behind  with  the  right  border 
of  the  lesser  omentum  and  its  vessels.  The  second  or  -perpendicular 
portion  is  situated  altogether  behind  the  peritoneum  ;  it  is  in  relation 

Fig.  180. 


by  its  anterior  surface  with  the  commencement  of  the  arch  of  the 
colon  ;  by  its  posterior  surface  with  the  concave  margin  of  the  right 
kidney,  the  inferior  vena  cava,  and  the  ductus  communis  chole- 
dochus;  by  its  right  border  with  the  ascending  colon;  and  by  its 
left  border  with  the  pancreas.  The  ductus  communis  choledochus 
and  pancreatic  duct  open  into  the  internal  and  posterior  side  of  the 
perpendicular  portion,  a  little  below  its  middle.  The  third  or  trans- 
verse portion  of  the  duodenum  lies  between  the  diverging  layers  of 
the  transverse  meso-colon,  with  which  and  with  the  stomach  it  is 
in  relation  in  front;  above  it  is  in  contact  with  the  lower  border  of 

Fig.  180.  A  vertical  and  longitudinal  section  of  the  stomach  and  duodenum,  made 
in  such  a  direction  as  to  include  the  two  orifices  of  the  stomach.  1.  The  oesophagus  ; 
upon  its  internal  surface  the  plicated  arrangement  of  the  cuticular  epithelium  is  shown. 
2.  The  cardiac  orifice  of  the  stomach,  around  wiiich  the  fringed  border  of  the  cuticular 
epithelium  is  seen.  3.  The  great  end  of  the  stomach.  4.  Its  lesser  or  pyloric  end. 
5.  The  lesser  curve.  6.  The  greater  curve.  7.  The  dilatation  at  the  lesser  end  of  the 
stomach  which  received  from  Willis  the  name  of  antrum  of  the  pylorus.  This  may 
be  regarded  as  the  rudiment  of  a  second  stomacii.  8.  The  rugae  of  the  stomach 
formed  by  the  mucous  membrane  :  their  longitudinal  direction  is  shown.  9.  The 
pylorus.  10.  The  oblique  portion  of  the  duodenum.  11.  The  descending  portion.  12. 
The  pancreatic  duct,  and  the  ductus  communis  choledochus  close  to  their  termination. 
13.  The  papilla  upon  which  the  ducts  open.  14.  The  transverse  portion  of  tiie  duo- 
denum. 15.  The  commencement  of  the  jejunum.  In  the  interior  of  the  duodenum 
and  jejunum,  the  valvulae  conniventes  are  seen. 

45 


530  JEJUNUM ILEUM CECUM — COLON. 

the  pancreas,  the  superior  mesenteric  artery  and  portal  vein  being 
interposed ;  and  behind  it  rests  upon  the  inferior  vena  cava  and  the 
aorta. 

The  Jejunum  (jejunus,  empty)  is  named  from  being  generally 
found  empty.  It  forms  the  upper  two-fifths  of  the  small  intestine  ; 
commencing  at  the  duodenum  on  the  left  side  of  the  second  lumbar 
vertebra,  and  terminating  in  the  ileum.  It  is  thicker  to  the  touch 
than  the  rest  of  the  intestine,  and  has  a  pinkish  tinge  from  contain- 
ing more  mucous  membrane  than  the  ileum. 

The  Ileum  {slXsiv,  to  twist,  to  convolute)  includes  the  remaining 
three-fifths  of  the  small  intestine.  It  is  somewhat  smaller  in  calibre, 
thinner  in  texture,  and  paler  than  the  jejunum  ;  but  there  is  no 
mark  by  which  to  distinguish  the  termination  of  the  one  or  the 
commencement  of  the  other.  It  terminates  in  the  right  iliac  fossa, 
by  opening  at  an  obtuse  angle  into  the  colon. 

The  jejunum  and  ileum  are  surrounded  above  and  at  the  sides  by 
the  colon  ;  in  front  they  are  in  relation  with  the  omentum  and  abdo- 
minal parietes;  they  are  retained  in  their  position  by  the  mesentery, 
which  connects  them  with  the  posterior  wall  of  the  abdomen  ;  and 
below  they  descend  into  the  cavity  of  the  pelvis.  At  about  the 
lower  third  of  the  ileum  a  pouch-like  process  or  diverticulum  of  the 
intestine  is  occasionally  seen.  This  is  a  remnant  of  embryonic  struc- 
ture, and  is  formed  by  the  obliteration  of  the  vitelline  duct  at  a 
short  distance  from  the  cylinder  of  the  intestine. 

Large  intestine. — The  large  intestine,  about  five  feet  in  length,  is 
sacculated  in  appearance,  and  is  divided  into  the  ccecum,  colon,  and 
rectum. 

The  CcBcum  (cascus,  blind)  is  the  blind  pouch,  or  cul-de-sac,  at 
the  commencement  of  the  large  intestine.  It  is  situated  in  the  right 
iliac  fossa,  and  is  retained  in  its  place  by  the  peritoneum,  which 
passes  over  its  anterior  surface;  its  posterior  surface  is  connected 
by  loose  cellular  tissue  with  the  iliac  fascia.  Attached  to  its  ex- 
tremity is  the  appendix  vermiformis,  a  long  worm-shaped  tube,  the 
rudiment  of  the  lengthened  caecum  found  in  all  mammiferous  animals 
except  man  and  the  higher  quadrumana.  The  appendix  varies  in 
length,  from  one  to  five  or  six  inches ;  it  is  about  equal  in  diameter 
to  a  goose-quill,  and  is  connected  with  the  posterior  and  left  aspect 
of  the  caicum  near  to  the  extremity  of  the  ileum.  It  is  usually  more 
or  less  coiled  upon  itself,  and  retained  in  that  coil  by  a  falciform 
duplicature  of  peritoneum.  Its  canal  is  extremely  small,  and  the 
orifice  by  which  it  opens  into  the  cascum  not  unfrequently  provided 
with  an  incomplete  valve.  Occasionally  the  peritoneum  invests  the 
oeecum  so  completely  as  to  constitute  a  meso-caicum,  which  per- 
mits of  an  unusual  degree  of  movement  in  this  portion  af  the  intes- 
tine, and  serves  to  explain  the  occurrence  of  hernia  of  the  caecum 
upon  the  left  side.  The  caecum  is  the  most  dilated  portion  of  the 
large  intestine. 

The  Colon  is  divided  into  ascending,  transverse,  and  descending. 
The  ascending  colon  passes  upwards  from  the  right  iliac  fossa, 


KECTUM.  531 

through  the  right  lumbar  region,  to  the  under  surface  of  the  Uver. 
It  then  bends  inwards,  and  crosses  the  upper  part  of  the  umbilical 
region  under  the  name  of  transverse  colon,  and  on  the  left  side  de- 
scends {descending  colon)  through  the  left  lumbar  region  to  the  left 
iliac  fossa,  where  it  makes  a  remarkable  curve  upon  itself,  which  is 
called  the  sigmoid  Jiexure. 

The  ascending  colon,  the  most  dilated  portion  of  the  large  intes- 
tine, next  to  the  caecum,  is  retained  in  its  position  in  the  abdomen 
either  by  the  peritoneum  passing  simply  in  front  of  it  or  by  a  narrow 
meso-colon.  It  is  in  relation  in  front  with  the  small  intestine  and 
with  the  abdominal  parietes  ;  behind  with  the  quadratus  lumborum 
muscle  and  with  the  right  kidney;  internally  with  the  small  intes- 
tine and  with  the  perpendicular  portion  of  the  duodenum;  and  by  its 
upper  extremity  with  the  under  surface  of  the  liver  and  with  the 
gall-bladder.  The  transverse  colon,  the  longest  portion  of  the  large 
intestine,  forms  a  curve  across  the  cavity  of  the  abdomen,  the  con- 
vexity of  which  looks  forwards  and  sometimes  downwards.  It  is 
in  relation  by  its  upper  surface  with  the  liver,  the  gall-bladder,  the 
stomach,  and  with  the  lower  extremity  of  the  spleen  ;  by  its  lower 
surface  with  the  small  intestine ;  by  its  anterior  surface  with  the 
anterior  layers  of  the  great  omentum  and  with  the  abdominal  pari- 
etes ;  and  by  its  jjosterior  surface  with  the  transverse  meso-colon. 
The  descending  colon  is  smaller  in  calibre,  and  is  situated  more 
deeply  than  the  ascending  colon.  Its  relations  are  precisely  similar. 
The  sigmoid  flexure  is  the  narrowest  part  of  the  colon  ;  it  curves  in 
the  first  place  upwards  and  then  downwards,  and  to  one  or  the 
other  side,  and  is  retained  in  its  place  by  a  meso-colon.  It  is  in 
relation  in  front  with  the  small  intestine  and  with  the  abdominal 
parietes ;  behind  with  the  iliac  fossa  ;  and  on  either  side  with  the 
small  intestine. 

The  Rectum  is  the  termination  of  the  large  intestine.  It  has  re- 
ceived its  name,  not  so  much  from  the  direction  of  its  course,  as 
from  the  straightness  of  its  form  in  comparison  with  the  colon.  It 
descends  from  opposite  the  left  sacro-iliac  symphysis,  in  front  of 
the  sacrum,  forming  a  gentle  curve  to  the  right  side,  and  then  re- 
turning to  the  middle  line;  near  the  extremity  of  the  coccyx  it 
curves  backwards  to  terminate  at  the  anus  at  about  an  inch  in  front 
of  the  apex  of  that  bone.  The  rectum,  therefore,  forms  a  double 
flexure  in  its  course,  the  one  being  directed  from  side  to  side,  the 
other  from  before  backwards.  It  is  smaller  in  calibre  at  its  upper 
part  than  the  sigmoid  flexure,  but  becomes  gradually  larger  as  it 
descends,  and  its  lower  extremity,  previously  to  its  termination  at 
the  anus,  forms  a  dilatation  of  considerable  but  variable  size. 

With  reference  to  its  relations,  the  rectum  is  divided  into  three 
portions;  the  j^rsi,  including  half  its  length,  extends  to  about  the 
middle  of  the  sacrum,  is  completely  surrounded  by  peritoneum,  and 
connected  to  the  sacrum  by  means  of  the  meso-rectum.  It  is  in  re- 
lation above  with  the  left  sacro-iliac  symphysis  and  below  with  the 
branches  of  the  internal  iliac  artery,  and  with  the  sacral  plexus  of 


532  STRUCTURE  OF  INTESTINES. 

nerves ;  one  or  two  convolutions  of  the  small  intestine  are  interposed 
beivi'een  the  front  of  the  rectum  and  the  bladder  in  the  male ;  and 
between  the  rectum  and  the  uterus  with  its  appendages  in  the  female. 
The  second  portion,  about  three  inches  in  length,  is  closely  attached 
to  the  surface  of  the  sacrum,  and  covered  by  the  peritoneum  only  in 
front;  it  is  in  relation  by  its  lower  part  with  the  base  of  ihe  bladder, 
vesiculse  seminales,  and  the  prostate  gland,  and  in  the  female  with 
the  vagina.  The  thii^d  portion  curves  backwards  from  opposite  the 
prostate  gland  to  terminate  at  the  anus;  it  is  embraced  by  the  leva- 
tores  ani,  and  is  about  one  inch  and  a  half  in  length.  It  is  separated 
from  the  membranous  portion  of  the  urethra  by  a  triangular  space; 
in  the  female  this  space  intervenes  between  the  vagina  and  the  rec- 
tum, and  constitutes  by  its  base  the  perineum. 

The  Anus  is  situated  at  a  little  more  than  an  inch  in  front  of  the 
extremity  of  the  coccyx.  The  integument  arourid  it  is  covered  with 
hairs,  and  is  drawn  into  numerous  radiated  plaits  which  are  oblite- 
rated during  the  passage  of  fosces.  The  margin  of  the  anus  is  pro- 
vided with  an  abundance  of  sebaceous  glands,  and  the  cuticle  may 
be  seen  terminating  by  a  fringed  and  scalloped  border,  at  a  few  lines 
above  the  extremity  of  the  opening. 

Structure  of  the  Intestinal  Canal. — The  pharynx  has  three  coats; 
a  mucous  coat,  a  fibrous  coat  derived  from  the  pharyngeal  fascia, 
and  a  muscular  layer.  The  oesophagus  has  but  two  coats,  the  mu- 
cous and  muscular.  The  stomach  and  intestines  have  three,  wztcows 
and  muscular,  and  an  external  serous  investment,  derived  from  the 
peritoneum. 

Mucous  coat. — The  mucous  membrane  of  the  mouth  invests  the 
■whole  internal  surface  of  that  cavity,  and  is  reflected  along  the 
parotid,  submaxillary,  and  sublingual  ducts,  into  the  corresponding 
glands.  It  terminates  anteriorly  upon  the  outer  margin  of  the  red 
border  of  the  lips,  and  posteriorly  is  continuous  with  the  mucous 
lining  of  the  pharynx.  The  mucous  membrane  of  the  pharynx 
is  continuous  with  the  mucous  lining  of  the  Eustachian  tubes,  the 
nares,  the  mouth  and  the  larynx.  In  the  oesophagus  it  is  thick,  very 
loosely  connected  with  the  muscular  coat,  and  is  disposed  in  longi- 
tudinal pHccB.  In  the  stomach  the  mucous  membrane  is  thin  and 
vascular  at  the  great  extremity,  and  becomes  thicker  and  lighter  in 
colour  towards  the  pyloric  extremity.  It  is  formed  into  plaits  or 
rugce,  which  are  disposed  for  the  most  part  in  a  longitudinal  direc- 
tion. The  rugae  are  most  numerous  towards  the  lesser  end  of  the 
stomach;  while  around  the  cardiac  orifice  they  assume  a  radiated 
arrangement.  At  the  pylorus  the  mucous  membrane  forms  a  cir- 
cular or  spiral  fold  which  constitutes  a  part  of  the  apparatus  of  the 
pyloric  valve.  In  the  lower  half  of  the  duodenum,  the  whole  length 
of  the  jejunum,  and  in  the  upper  part  ol  the  ileum,  it  forms  valvular 
folds  called  voIvuIcb  conniventes,  which  are  several  lines  in  breadth 
in  the  lower  part  of  the  duodenum  and  upper  portion  of  the  jejunum, 
and  diminish  gradually  in  size  towards  each  extremity.  These 
folds  do  not  entirely  surround  the  cylinder  of  the  intestine,  but  ex- 


POUCHES  AND  COLUMNS  OF  RECTUM.  533 

tend  for  about  one  half  or  three-fourths  of  its  circumference.  In  the 
lower  half  of  the  ileum  the  mucous  lining  is  without  folds;  hence 
the  thinness  of  the  coats  of  this  intestine  as  compared  with  the  jeju- 
num and  duodenum.  At  the  termination  of  the  ileum  in  the  c^cum, 
the  mucous  membrane  forms  two  folds,  which  are  strengthened  by 
the  muscular  coat,  and  project  into  the  caecum.  These  are  the  ilio- 
ccEcal  valve  (Valvula  Bauhini).  In  the  caecum  and  colon  the  mucous 
membrane  is  raised  into  crescentic  folds,  which  correspond  with  the 
sharp  edges  of  the  sacculi ;  and,  in  the  rectum,  it  forms  three  val- 
vular folds,*  one  of  which  is  situated  near  the  commencement  of  the 
intestine ;  the  second,  extending  from  the  side  of  the  tube,  is  placed 
opposite  the  middle  of  the  sacrum ;  and  the  third,  which  is  the 
largest  and  most  constant,  projects  from  the  anterior  wall  of  the 
intestine  opposite  the  base  of  the  bladder.  Besides  these  folds,  the 
membrane  in  the  empty  state  of  the  intestine  is  thrown  into  longitu- 
dinal plaits,  somewhat  similar  to  those  of  the  oesophagus ;  these 
have  been  named  the  columvs  of  the  rectum.f 

Structure  of  Mucous  Membrane. — This  membrane  is  analogous  to 
the  cutaneous  covering  of  the  exterior  of  the  body,  and  resembles 
that  tissue  very  closely  in  its  structure.  It  is  composed  of  three 
layers,  an  epitlieUum,  a  proper  mucous,  and  a  fibrous  layer. 

The  Epithelium  is  the  cuticle  of  the  mucous  membrane.  Through- 
out the  pharynx  and  oesophagus  it  resembles  the  cuticle,  both  in 
appearance  and  character.  It  is  continuous  with  the  cuticle  of  the 
skin  at  the  margin  of  the  lips,  and  terminates  by  an  irregular  bor- 
der at  the  cardiac  orifice  of  the  stomach.  At  the  opposite  extre- 
mity of  the  canal  it  terminates  by  a  scalloped  border  just  within  the 
verge  of  the  anus.  In  the  mouth  it  is  composed  of  several  laminas 
of  oval  vesicles  and  thin  angular  scales.  Each  vesicle  and  each 
scale  possesses  a  central  nucleus,  and  within  the  nucleus  is  a  minute 
nucleus-corpuscle.  According  to  Mr.  NasmylhJ  the  deepest  laminae 
of  the  epithelium  appears  to  consist  of  nuclei  only,  in  the  next  the 
investing  vesicle  is  developed  ;  the  vesicles  by  degrees  enlarge  and 
become  flattened,  and  in  the  superficial  laminas  are  converted  into 
thin  scales.  .The  nuclei,  the  vesicles,  and  the  scales,  are  connected 
together  by  a  glutinous  fluid  of  the  consistence  of  jelly,  which  con- 
tains an  abundance  of  minute  opaque  granules.  The  scales  of  the 
superficial  layer  overlap  each  other  by  their  margins.  During  the 
natural  functions  of  the  mucous  membrane  the  superficial  scales 
exfoliate  continually  and  give  place  to  the  deeper  layers.     In  the 

*  Mr.  Houston,  "On  the  Mucous  Membrane  of  the  Rectum."  Dublin  Hospital  Re- 
ports, vol.  V, 

t  The  spaces  between  the  columns  of  the  rectum  become  closed  at  the  anus  so  as  to 
form  a  series  of  pouches  represented  in  the  accompanying  cut.  These  pouches  are 
sometimes  dilated  and  produce  a  disease  first  described  by  Dr.  Physick.  (See  Gibson's 
Surgery.)  The  mucous  membrane  of  the  rectum  is  connected  to  the  muscular  coat 
by  a  very  loose  cellular  tissue  as  in  the  cesoph:igus. — G. 

X  Investigations  into  the  structure  of  the  Epithelium,  presented  to  the  medical  sec- 
tion of  liie  British  Medical  Association,  in  1830,  published  in  a  work  entitled  "  Three 
Memoirs  on  the  Developement  of  the  Teeth  and  Lpithelium."  1841. 

45* 


534 


STRUCTURE  OF  MUCOUS  MEMBRANE. 


Stomach  and  intestines  these  bodies  are  pyriform  in  shape,  and  have 
a  columnar  arrangement,  the  apices  being  applied  to  the  papillary 

Fig.  181. 


surface  of  the  membrane,  and  the  bases  forming  by  their  approxi- 
mation the  free  intestinal  surface.  Each  column  is  provided  with 
a  central  nucleus  and  nucleus-corpuscle,  which  gives  to  its  middle 
a  swollen  appearance;  and,  from  the  transparency  of  its  structure, 
the  nucleus  may  be  seen  through  the  base  of  the  column,  when 
examined  from  the  surface.  Around  the  circular  villi  the  columns, 
from  being  placed  perpendicularly  to  the  surface,  have  a  radiated 
arrangement.  The  columnar  epithelium  is  produced  in  the  same 
manner  with  the  laminated  epithelium,  in  nuclei,  vesicles,  and 
columns,  and  the  latter  are  continually  thrown  off  to  give  place  to 
successive  layers. 

The  Proper  mucous,  or  Papillary  layer,  is  analogous  to  the  papil- 
lary layer  of  the  skin,  and,  like  it,  is  the  secreting  structure  by 


Fi^.  181.  A  vertical  section  of  the  anterior  parietes  of  the  anus,  with  the  whole 
canal  displayed  so  as  to  show  the  relations  of  the  sacculi  of  the  middle  region,  and 
their  relations  to  the  surrounding  parts,  their  orifices  being  marked  witfi  bristles.  1,  1. 
Columns  of  the  rectum.  2,2.  Rudiments  of  columns.  3.  Internal  sphincter.  4.  Ex- 
ternal  sphincter.  6.  Rudimentary  or  imperfect  sacculi.  5,  5.  Radiated  folds  of  the 
skin,  terminating  on  the  surface  of  the  nates.     7.  A  bristle  in  one  of  the  sacs. — G. 


HUMOURS  OF  THE  EYE.  535 

which  the  epithelium  is  produced.  Its  surface  presents  several 
varieties  of  appearance  when  examined  in  the  different  parts  of  its 
extent.  In  the  stomach  it  forms  polygonal  cells,  into  the  floor  of 
which  the  gastric  follicles  open.  In  the  small  intestine  it  presents 
numerous  minute,  projecting  papillae,  called  villi.  The  villi  are  of 
two  kinds,  cylindrical  and  laminated,  and  so  abundant  as  to  give 
to  the  entire  surface  a  beautiful  velvety  appearance.  In  the  large 
intestine  the  surface  is  composed  of  a  fine  network  of  minute  poly- 
gonal cells,  moie  numerous  than  those  of  the  stomach,  but  resem- 
bling them  in  receiving  the  secretion  from  numerous  perpendicular 
follicles  into  their  floors.* 

The  Fibrous  layer  (submucous,  nervous)  is  the  membrane  of 
support  to  the  mucous  membrane,  as  is  the  corium  to  the  papillary 
layer  of  the  skin.  It  gives  to  the  mucous  membrane  its  strength 
and  resistance,  is  but  loosely  connected  with  the  mucous  layer,  but 
is  firmly  adherent  to  the  muscular  stratum,  and  is  called,  in  the 
older  works  on  anatomy,  the  "  nervous  coat" 

In  the  loose  cellular  tissue  connecting  the  mucous  with  the  fibrous 
layer,  are  situated  the  glands  and  folUcles  belonging  to  the  mucous 
membrane :  these  are  the — 

Pharyngeal  glands, 
(Esophageal  glands, 
Gastric  follicles, 
Duodenal  glands,  (Brunner's). 
^  Glandulae  solitarise, 

Glandulse  aggregates  (Peyer's), 
Simple  follicles  (Lieberkiihn's). 

The  Pharyngeal  glands  are  situated  in  considerable  numbers 
beneath  the  mucous  membrane  of  the  pharynx,  particularly  around 
the  posterior  nares.  Two  of  these  glands,  of  larger  size  than  the 
rest,  and  lobulated  in  structure,  occupy  the  margin  of  the  opening 
of  the  Eustachian  tube. 

The  (Esop/iagea.l  glands  are  small  lobulated  bodies,  situated  in 
the  submucous  tissue,  and  opening  upon  the  surface  of  the  oeso- 
phagus by  a  long  excretory  duct,  which  passes  obliquely  through 
the  mucous  membrane. 

The  Gastric  follicles  are  long  tubular  follicular  glands,  situated 
perpendicularly  side  by  side  in  every  part  of  the  mucous  membrane 
of  the  stomach.  At  their  terminations  they  are  dilated  into  small 
lateral  pouches,  which  give  them  a  clustered  appearance.  This 
character  is  more  clearly  exhibited  at  the  pyloric  than  at  the  car- 
diac end  of  the  stomach.  They  are  intended,  very  probably,  for 
the  secretion  of  the  gastric  fluid. 

*  The  first  notice  of  the  true  structure  of  mucous  membrane  appeared  in  the 
American  Journal  of  Medical  Sciences,  and  was  from  the  pen  of  Professor  Horner. 
The  preparations  which  he  made  at  tiie  time  are  in  the  Wistar  Museum,  and  illustrate 
the  structure  beautifully. — G, 


536 


GLANDS  OF  INTESTINES. 


The  Duodenal  or  Brunner's glands*  are  small  flattened  granular 
bodies,  compared  collectively  by  Von  Brunn  to  a  second  pancreas. 
They  resemble  in  structure  the  small  salivary  glands,  so  abundant 
beneath  the  mucous  membrane  of  the  mouth  and  lips;  and,  like 
them,  they  open  upon  the  surface  by  minute  excretory  ducts. 
They  are  limited  to  the  duodenum. 

The  Solitary  glands  are  of  two  kinds,  those  of  the  small  and 
those  of  the  large  intestine.  The  former  are  small  circular  patches, 
surrounded  by  a  zone  or  wreath  of  simple  follicles.  When  opened, 
they  are  seen  to  consist  of  a  small  flattened  saccular  cavity,  con- 
taining a  mucous  secretion,  but  having  no  excretory  duct.  They 
are  chiefly  found  in  the  lower  part  of  the  ileum.  The  solitary 
glands  of  the  large  intestine  are  most  abundant  in  the  caecum  and 
appendix  cseci;  they  are  small  circular  projections,  flattened  upon 
the  surface,  and  perforated  in  the  centre  by  a  minute  excretory 
opening. 

The  Aggregate  or  Peyer's  glands;]  are  situated  near  to  the  lower 
end  of  the  ileum,  and  occupy  that  portion  of  the  intestine  which  is 

opposite  the  attachment  of  the 
mesentery.  To  the  naked  eye 
they  present  the  appearance  of 
oval  disks,  covered  with  small 
irregular  fissures;  but  with  the 
aid  of  the  microscope  they  are 
seen  to  be  composed  of  nume- 
rous small  circular  patches, 
surrounded  by  simple  follicles, 
like  the  solitary  glands  of  the 
small  intestine.  Each  patch 
corresponds  with  a  flattened 
and  closed  sac,  situated  be- 
neath the  membrane,  but  hav- 
ing no  excretory  opening,  and 
the  interspace  between  the 
patches  is  occupied  by  flat- 
tened villi. 
The  Simple  follicles,  or  follicles  of  Lieberkuhn,  are  small  pouches 
of  the  mucous  layer,  dispersed  in  immense  numbers  over  every  part 
of  the  mucous  membrane. 

Muscular  coat. — The  muscular  coat  of  the  pharynx  consists  of 
five  pairs  of  muscles,  which  have  been  already  described.  The 
muscular  coat  of  the  rest  of  the  alimentary  canal  is  composed  of 
two  planes  of  fibres,  an  external  longitudinal,  and  an  internal 
circular. 


Fig.  182. 


Fig.  182.  Portion  of  one  of  the  patches  of  Pcycr's  glands  from  the  end  of  the 
ileum:  highly  magnified.     The  villi  are  also  shown. — (Boehm.) 

*  John  (;onrad  von  Rrunn ;  "Glandulne  Duodcni  sen  Pancreas  Sccundarium,"  1715. 

t  Jolin  Conrad  Peycr,  an  anatomist  of  Schauft'hauaen,  in  Switzerland.  His  essay, 
"De  Glandulis  Intcstinorum,"  was  pjublished  in  1677. 


MUSCULAR  COAT.  537 

The  (Esophagus  is  very  muscular;  its  longitudinal  fibres  are  con- 
tinuous above  with  the  pharynx,  and  are  attached  in  front  to  the 
vertical  ridge  on  the  posterior  surface  of  the  cricoid  cartilage ;  the 
uppermost  circular  fibres  are  also  attached  on  each  side  to  the 
cricoid  cartilage.  Belovv^,  both  sets  of  fibres  are  continued  upon 
the  stomach.  On  the  stomach  the  longitudinal  fibres  are  most  appa- 
rent along  the  lesser  curve,  and  the  circular  at  the  smaller  end.  At 
the  pylorus  the  latter  are  aggregated  into  a  thick  circular  ring, 
which,  with  the  spiral  fold  of  mucous  membrane,  constitutes  the 
pyloric  valve.  At  the  great  end  of  the  stomach  a  new  order  of 
fibres  is  introduced,  having  for  their  object  to  strengthen  and  com- 
press that  extremity  of  the  organ.  They  are  directed  more  or  less 
horizontally  from  the  great  end  towards  the  lesser  end,  and  are 
generally  lost  upon  the  sides  of  the  stomach  at  about  its  middle : 
these  are  the  oblique  fibres. 

The  Small  intestine  is  provided  with  both  layers,  equally  distri- 
buted over  the  entire  surface.  At  the  termination  of  the  ileum  the 
circular  fibres  are  continued  into  the  two  folds  of  the  ilio-caecal 
valve,  while  the  longitudinal  fibres  pass  onwards  to  the  large  intes- 
tine. In  the  large  intestine  the  longitudinal  fibres  commence  at 
the  appendix  vermiformis  and  are  collected  into  three  bands,  an 
anterior,  broad ;  and  two  posterior  and  narrower  bands.  These 
bands  are  nearly  one  half  shorter  than  the  intestine,  and  give  to  it 
the  sacculated  appearance  which  is  characteristic  of  the  csecum 
and  colon.  In  the  descending  colon  the  posterior  bands  usually  unite 
and  form  a  single  band.  From  this  point  the  two  bands  are  con- 
tinued downwards  upon  the  sigmoid  flexure  to  the  rectum,  around 
which  they  syjread  out  and  form  a  thick  and  very  muscular  lon- 
gitudinal layer.  The  circular  fibres  in  the  csecum  and  colon  *are 
exceedingly  thin;  in  the  rectum  they  are  thicker,  and  at  its  lower 
extremity  they  are  aggregated  into  the  thick  muscular  ring  which 
is  called  the  internal  sphincter  ani.* 

Serous  Coat. — The  pharynx  and  cEsophagus  have  no  covering 
of  serous  membrane.  The  alimentary  canal  within  the  abdomen 
has  a  serous  layer,  derived  from  the  peritoneum. 

The  Stomach  is  completely  surrounded  by  the  peritoneum  ex- 
cepting along  the  line  of  junction  of  the  great  and  lesser  omentum. 
The  Jirst  or  oblique  portion  of  the  duodenum  is  also  completely  in- 

*  Mr.  Wilson  does  not  seem  to  have  paid  the  same  close  attention  to  the  anatomy  of 
the  anus  as  to  otiier  parts  of  the  body,  and  we  here  find  a  deficiency  in  the  description 
which  we  shall  endeavour  to  supply. 

The  Muscular  coat  of  the  rectum  consists  of  much  stronger  fasciculi  than  that  of 
the  colon  ;  the  transverse  fibres  terminate  at  the  anus  by  aggregating  into  a  ring  which 
is  called  the  internal  sphincter  muscle,  as  in  1  fig.  183.  The  longitudinal  fibres  being 
outside  of  the  transverse,  when  they  reach  the  internal  sphincter  wind  around  it  and 
are  inserted  into  the  submucous  coat  from  one  to  four  inches  above  the  anus.  They 
tlms  form  a  pulley-like  arrangement  which  everts  the  mucous  membrane  in  defecation 
and  is  the  active  agent  in  producing  prolapsus  ani.  I  have  observed  that  when  hEcmor- 
rhoids  exist  many  of  the  fibres  run  to  be  inserted  into  then),  hence  their  ready  extru- 
sion when  the  patient  is  directed  to  force  them  down.  The  following  cut  exhibits  this 
arrangement.     See  Horner's  Special  Anatomy,  1836. — G, 


53S 


VESSELS  OF  INTESTINES. 


Fig.  183. 


eluded  by  the  serous  membrane  with  the  exception  of  the  points 
of  attachment  of  the  omenta.  The  descending  'portion  has  merely 
"a  partial  covering  on  its  anlerior  surface.  The  transverse  portion 
is  also  behind  the  peritoneum,  being  situated  between  the  two  layers 
of  the  transverse  meso-colon,  and  has  but  a  partial  covering.  The 
rest  of  the  small  intestine  is  completely  invested  by  it,  excepting 
along  the  concave  border  to  which  the  mesentery  is  attached.  The 

ccBcum  is  more  or  less  invested 
by  the  peritoneum,  the  more  fre- 
quent disposition  being  that  in 
which  the  intestine  is  surrounded 
for  three-fourths  only  of  its  cir- 
cumference. The  ascending  and 
the  descending  colon  are  covered 
by  the  serous  membrane  only  in 
front.  The  transverse  colon  is 
invested  completely,  with  the  ex- 
ception of  the  lines  of  attachment 
of  the  greateromentum  and  trans- 
'"^  verse  meso-colon.  And  the  sig- 
moid Jlexure  is  entirely  surround- 
ed, with  the  exception  of  the  part 
corresponding  with  the  junction 
of  the  left  meso-colon.  The  upper 
third  of  the  rectum  is  completely 
enclosed  by  the  peritoneum  ;  the 
middle  third  has  an  anterior  co- 
vering only,  and  the  inferior  third 
*  none  whatsoever. 

Vessels  and  Nerves. — The  Arteries  of  the  alimentary  canal,  as 
they  supply  the  tube  from  above  downwards,  are  the  pterygo-pala- 
tine,  ascending  pharyngeal,  superior  thyroid,  and  inferior  thyroid  in 
the  neck;  oesophageal  in  the  thorax;  gastric,  hepatic,  splenic,  supe- 
rior and  inferior  mesenteric  in  the  abdomen ;  and  inferior  mesenteric, 
iliac,  and  internal  pudic  in  the  pelvis.  The  veins  from  the  abdomi- 
nal alimentary  canal  unite  to  form  the  vena  portse.  The  lymphatics 
and  lacteals  open  into  the  thoracic  duct. 

The  Nerves  of  the  pharynx  and  oesophagus  are  derived  from  the 


Fig.  183.  A  vertical  section  of  the  parietes  of  the  anus,  passing;  throug^h  the  middle 
line  of  one  of  the  columns  of  the  rectum,  and  the  neig'hbouring'  parts,  1.  The  internal 
sphincter,  with  its  arched  fibres  transversely  divided.  2,  2.  I'he  plane  of  arched  fibres 
of  the  muscular  coat,  similarly  divided.  3.  The  point  of  fjreatest  contraction  of  the  in- 
ternal sphincter.  4.  The  external  sphincter.  .5.  Tlie  point  of  greatest  contraction  of 
the  same  muscle.  6.  The  |>lano  of  longitudinal  fibres  of  the  muscular  coat,  longitudi- 
nally  divided.  7.  Some  of  tlicse  fibres  terminating  in  the  internal  sphincter.  8.  Others, 
terminating  in  the  external  sphincter.  D.  The  remaining  longitudinal  fibres,  collected 
into  a  semitendinous  fasciculus,  passing  over  the  lower  mai'gin  of  the  internal  sphincter, 
to  he  reverted  upward  within  tlie  duplicature  of  the  column.  10.  'I'hcse  reverted  fibres 
again  becoming  muscular,  and  terminating  in  the  macous  coat.  11.  The  mucous  coat. 
12    A  bristle  m  one  of  the  sacs. — G. 


THE  LIVER. 


539 


glosso-pharyngeal,  pneumogastric,  and  sympathetic.  The  nerves 
of  the  stomach  are  the  pneumogastric  and  sympathetic  branches 
from  the  solar  plexus ;  and  those  of  the  intestinal  canal  are  the 
superior  and  inferior  mesenteric  and  hypogastric  plexuses.  The 
extremity  of  the  rectum  is  supplied  by  the  coccygeal  nerves  from 
the  spinal  cord. 


THE    LIVER. 


The  liver  is  a  conglomerate  gland  of  large  size,  appended  to  the 
alimentary  canal,  and  performing  the  double  office  of  separating 
impurities  from  the  venous  blood  of  the  chylo-poietic  viscera  pre- 
viously to  its  return  into  the  general  venous  circulation,  and  of 
secreting  a  fluid  necessary  to  chylification,  the  bile.  It  is  the 
largest  organ  in  the  body,  weighing  about  four  pounds,  and 
measuring  through  its  longest  diameter  about  twelve  inches.  It  is 
situated  in  the  right  hypochondriac  region,  and  extends  across  the 
epigastrium  into  the  left  hypochondriac,  frequently  reaching  by  its 
left  extremity  to  the  upper  end  of  the  spleen.  It  is  placed  obliquely 
in  the  abdomen;  its  convex  surface  looking  upwards  and  forwards, 
and  the  concave  downwards  and  backwards.  The  anterior  border 
is  sharp,  free,  and  marked  by  a  deep  notch,  the  posterior  i'ounded 
and  broad.  It  is  in  relation,  superiorly  and  posteriorly  with  the 
diaphragm,  and  inferiorly  with  the  stomach,  ascending  portion  of 
the  duodenum,  transverse  colon,  right  supra-renal  capsule  and  right 
kidney,  and  corresponds  by  its  free  border  with  the  lower  margin 
of  the  ribs. 

Fig.  184. 


The  liver  is  retained  in  its  place  by  five  ligaments  ;  four  of  which 
are  formed  by  duplicatures  of  the  peritoneum,  and  are  situated 
upon  the  convex  surface  of  the  organ ;  the  fifth  being  a  fibrous 

Fig:.  184.  The  upper  surface  of  the  liver.  1.  The  right  lobe.  2.  The  left  lobe.  3, 
The  anterior  or  free  border.  4.  The  posterior  or  rounded  border.  5.  The  broad  liga- 
ment. 6.  The  round  ligament.  7,  7,  The  two  lateral  ligaments.  8,  8.  The  space 
left  uncovered  by  tlie  peritoneum,  and  surrounded  by  the  coronary  ligament.  9.  The 
inferior  vena  cava.  10.  The  point  of  the  lobus  Spigelii.  3.  The  fundus  of  the  gall- 
bladder seen  projecting  beyond  the  anterior  border  of  the  right  lobe. 


540  LIGAMENTS  OF  THE  LIVER. 

cord  which  passes  through  a  fissure  in  its  under  surface,  from  the 
umbilicus  to  the  inferior  vena  cava.     They  are  the — ■ 

Longitudinal, 
Two  lateral, 
Coronary, 
Round. 

The  Lovgitudinal  ligament  (broad,  ligamentum  suspensorium 
hepatis)  is  an  antero-posterior  fold  of  peritoneum,  extending  from 
the  notch  on  the  anterior  margin  of  the  liver  to  its  posterior  border. 
Between  its  two  layers  in  the  anterior  and  free  margin  is  the  round 
ligament. 

The  two  Lateral  ligaments  are  formed  by  the  two  layers  of  peri- 
toneum, which  pass  from  the  under  surface  of  the  diaphragm  to 
the  posterior  border  of  the  liver;  they  correspond  with  its  lateral 
lobes. 

The  Coronary  ligament  is  formed  by  the  separation  of  the  two 
layers  forming  the  lateral  ligaments  near  their  point  of  convergence. 
The  posterior  layer  is  continued  unbroken  from  one  lateral  ligament 
into  the  other;  but  the  anterior  quits  the  posterior  at  each  side,  and 
is  continuous  with  the  corresponding  layer  of  the  longitudinal  liga- 
ment. In  this  way  a  large  oval  surface  on  the  posterior  border  of 
the  liver  is  left  uncovered  by  peritoneum,  and  is  connected  to  the 
diaphragm  by  a  dense  cellular  tissue.  This  space  is  formed  prin- 
cipally by  the  right  lateral  ligament,  and  is  pierced  near  its  left 
extremity  by  the  inferior  vena  cava,  previously  to  the  passage  of 
that  vessel  through  the  tendinous  opening  in  the  diaphragm. 

The  Round  ligament  is  a  fibrous  cord  resulting  from  the  oblitera- 
tion of  the  umbilical  vein,  and  situated  between  the  two  layers  of 
peritoneum  in  the  anterior  border  of  the  longitudinal  ligament.  It 
may  be  traced  from  the  umbilicus,  along  the  longitudinal  fissure 
upon  the  under  surface  of  the  liver  to  the  inferior  vena  cava,  to 
which  it  is  connected. 

The  under  surface  of  the  liver  is  marked  by  five  fissures  which 
divide  its  surface  into  five  compartments  or  lobes,  two  principal 
and  three  minor  lobes ;  they  are  the — 

Fissures.  Lobes. 

Longitudinal  fissure,     .  Right  lobe, 

Fissure  of  the  ductus  venosus,  Left  lobe. 

Transverse  fissure,  Lobus  quadratus, 

Fissure  for  the  gall-bladder,  Lobus  Spigelii, 

Fissure  for  the  vena  cava.  Lobus  caudatus. 

The  Longitudinal  fissure  is  a  deep  groove  running  from  the  notch 
upon  the  anterior  margin  of  the  liver,  to  the  posterior  border  of  the 
organ.  At  about  one-third  from  its  posterior  extremity  it  is  joined 
by  a  short  but  deep  fissure,  the  transverse,  which  meets  it  trans- 
versely from  the  under  part  of  the  right  lobe. 


FISSURES  OF  THE  LIVER.  541 

The  longitudinal  fissure  in  front  of  this  junction  lodges  the  fibrous 
cord  of  the  umbilical  vein,  and  is  generally  crossed  by  a  band  of 
hepatic  substance  called  the  pons  hepatis. 

Fig.  185. 


The  Fissure  for  the  ductus  venosus  is  the  shorter  portion  of  the 
longitudinal  fissure,  extending  from  the  junctional  termination  of  the 
transverse  fissure  to  the  posterior  border  of  the  liver,  and  contain- 
ing a  small  fibrous  cord,  the  remains  of  the  ductus  venosus.  This 
fissure  is  therefore  but  a  part  of  the  longitudinal  fissure. 

The  Transverse  fissure  is  the  short  and  deep  fissure,  about  two 
inches  in  length,  through  which  the  hepatic  ducts,  hepatic  artery, 
and  portal  vein  enter  the  liver.  Hence  this  fissure  was  considered 
by  the  older  anatomists  as  the  gate  (porta)  of  the  liver;  and  the 
large  vein  entering  the  organ  at  this  point,  the  portal  vein.  At  their 
entrance  into  the  transverse  fissure  the  branches  of  the  hepatic  duct 
are  the  most  anterior,  next  those  of  the  artery,  and  most  posteriorly 
the  portal  vein. 

The  Fissure  for  the  gall-bladder  is  a  shallow  fossa  extending  for- 
wards, parallel  with  the  longitudinal  fissure,  from  the  right  extre- 
mity of  the  transverse  fissure  to  the  free  border  of  the  liver,  where 
it  frequently  forms  a  notch. 

The  Fissure  of  the  vena  cava  is  a  deep  and  short  fissure  occa- 
sionally a  rounded  tunnel,  which  proceeds  from  a  little  behind  the 

Fig.  185.  Tiie  under  surface  of  the  liver.  1.  The  right  lobe.  2.  The  left  lobo.  3. 
The  lobus  quadratus.  4.  The  lobus  Spigclii.  5.  The  lobus  caudatus.  6.  The  longi- 
tudinal  fissure,  in  which  is  seen  the  rounded  cord;  the  remains  of  the  umbilical  vein. 
7.  The  pons  liepitis.  8.  The  fissure  for  the  ductus  venosus;  the  obliterated  cord  of 
the  ductus  is  seen  passing  backwards  to  be  attached  to  the  coats  of  the  inferior  vena 
cava  9.  10.  The  gall-bladder  lodged  in  its  fossa.  11.  The  transverse  fissure,  con- 
taining from  before  backwards,  the  hepatic  duct,  hepatic  artery,  and  portal  vein.  12. 
The  vena  cava.  13.  A  depression  corresponding  witli  the  curve  of  the  colon.  14.  A 
double  depression  produced  by  the  right  kidney  and  its  supra-renal  capsule.  15.  The 
rough  surface  on  the  posterior  border  of  llie  liver  left  uncovered  by  peritoneum ;  the 
cut  edge  of  peritoneum  surrounding  this  surface  forms  part  of  llie  coronary  ligament. 
16.  The  notch  on  the  anterior  border,  separating  the  two  lobes.  17.  The  notch  on  the 
posterior  border,  corresponding  with  the  vertebral  column. 

46 

.  r 


542  LOBES  OF  THE  LIVER. 

right  extremity  of  the  transverse  fissure  to  the  posterior  border  of 
the  liver,  and  lodges  the  inferior  vena  cava. 

These  five  fissures  taken  collectively  resemble  an  inverted  y, 
the  base  corresponding  with  the  free  margin  of  the  liver,  and  the 
apex  with  its  posterior  border.  Viewing  them  in  this  way,  the  two 
anterior  branches  represent  the  longitudinal  fissure  on  the  left,  and 
the  fissure  for  the  gall-bladder  on  the  right  side;  the  two  posterior, 
the  fissure  for  the  ductus  venosus  on  the  left,  and  the  fissure  for  the 
vena  cava  on  the  right  side,  and  the  connecting  bar  the  transverse 
fissure. 

Lobes. — The  Right  lobe  is  four  or  six  times  larger  than  the  left, 
from  which  it  is  separated  on  the  concave  surface  by  the  longitu- 
dinal fissure,  and  on  the  convex  by  the  longitudinal  ligament.  It  is 
marked  upon  its  under  surface  by  the  transverse  fissure,  and  by  the 
fissures  for  the  gall-bladder  and  vena  cava,  and  presents  three  de- 
pressions, one  in  front  for  the  curve  of  the  ascending  colon,  and 
two  behind  for  the  right  supra-renal  capsule,  and  kidney. 

The  Left  lobe  is  small  and  flattened,  convex  upon  its  upper  sur- 
face, and  concave  below,  where  it  lies  in  contact  with  the  anterior 
surface  of  the  stomach.  It  is  sometimes  in  contact  by  its  extremity 
with  the  upper  end  of  the  spleen,  and  is  in  relation  by  its  posterior 
border  with  the  cardiac  orifice  of  the  stomach,  and  left  pneumo- 
gastric  nerve. 

The  lobus  quadratus  is  a  quadrilateral  lobe  situated  upon  the 
under  surface  of  the  right  lobe  :  it  is  bounded  in  front  by  the  free 
border  of  the  liver;  behind  by  the  transverse  fissure  ;  to  the  right 
by  the  gall-bladder;  and  to  the  left  by  the  longitudinal  fissure. 

The  Lobus  Spigelii*  is  a  small  triangular  lobe,  also  situated  upon 
the  under  surface  of  the  right  lobe :  it  is  bounded  in  front  by  the 
transverse  fissure ;  and  on  the  sides  by  the  fissures  for  the  ductus 
venosus  and  vena  cava. 

The  Lobus  cauddlus  is  a  small  tail-like  appendage  to  the  lobus 
Spigelii,  from  which  it  runs  outwards  like  a  crest  into  the  right 
lobe,  and  serves  to  separate  the  right  extremity  of  the  transverse 
fissure  from  the  commencement  of  the  fissure  for  the  vena  cava.  In 
some  livers  this  lobe  is  extremely  well-marked,  in  others  it  is  small 
and  ill-defined. 

Reverting  to  the  comparison  of  the  fissures  with  an  inverted  y,  it 
will  be  observed  that  the  quadrilateral  interval,  in  front  of  the  trans- 
verse bar,  represents  the  lobus  quadratus;  the  triangular  space 
behind  the  bar,  represents  the  Spigelii ;  and  the  apex  of  the  letter, 
the  point  of  union  between  the  inferior  vena  cava,  and  the  remains 
of  the  ductus  venosus. 

The  Vessels  entering  into  the  structure  of  the  liver  are  alsOj^oe  in 
number;  they  are,  the 

♦Adrian  Spig-el,  a  Bclfjian  phyRicinn,  professor  at  Padua  after  Casserius  in  1616. 
He  assigned  considerahlc  importance  to  this  little  lobe,  but  it  had  been  described  by 
Sylvius  full  sixty  years  before  his  time. 


STHtJCTURE  OP  THE  LIVER.  543 

Hepatic  artery, 
Portal  vein, 
Hepatic  veins. 
Hepatic  ducts, 
Lynnphatics. 

The  Hematic  artery,  'portal  vein,  and  hepatic  duct  enter  the  liver 
at  the  transverse  fissure,  and  ramify  through  portal  canals  to  every 
part  of  the  organ;  so  that  their  general  direction  is  from  below 
upwards,  and  from  the  centre  towards  the  circumference. 

The  Hepatic  veins  commence  at  the  circumference  and  proceed 
from  before  backwards,  to  open  into  the  vena  cava,  on  the  posterior 
border  of  the  liver.  Hence  the  branches  of  the  two  veins  cross  each 
other  in  their  course. 

The  portal  vein,  hepatic  artery,  and  duct  are  moreover  enveloped 
in  a  loose  cellular  tissue,  the  capsule  of  Glisson,  which  permits  them 
to  contract  upon  themselves  when  emptied  of  their  contents  ;  the 
hepatic  veins,  on  the  contrary,  are  closely  adherent  by  their  parietes 
to  the  surface  of  the  canals  in  which  they  run,  and  are  unable  to 
contract.  By  these  characters  the  anatomist  is  enabled,  in  any  sec- 
tion of  the  liver,  to  distinguish  at  once  the  most  minute  branch  of 
the  portal  vein  from  the  hepatic  vein ;  the  former  will  be  found  more 
or  less  collapsed,  and  always  accompanied  by  an  artery  and  duct, 
and  the  latter  widely  open  and  solitary. 

The  Lymphatics  are  described  in  the  chapter  dedicated  to  those 
vessels. 

The  Nerves  of  the  liver  are  derived  from  the  systems  both  of 
animal  and  of  organic  life  ;  the  former  proceed  from  the  right 
phrenic  and  pneumogastric  nerves,  and  the  latter  from  the  hepatic 
plexus. 

Structure  and  Minute  Anatomy  of  the  Liver,  according  to  Mr. 

Kiernan. 

The  Liver  is  composed  of  lobules,  of  a  connecting  medium,  called 
Glisson^s  capsule,  of  the  ramifications  of  the  portal  vein,  hepatic  duct 
hepatic  artery,  hepatic  veins,  lymphatics,  and  nerves,  and  is  enclosed 
and  retained  in  its  proper  situation  by  the  peritoneum.  I  shall 
describe  each  of  these  structures  singly,  following  rigidly  the  dis- 
coveries of  Mr.  Kiernan. 

1.  The  Lobules  are  small  granular  bodies,  of  about  the  size  of  a 
millet  seed,  of  an  irregular  form,  and  presenting  a  number  of 
rounded  projecting  processes  upon  their  surface.  When  divided 
longitudinally,  they  have  a  foliated  appearance,  and  transversely,  a 
polygonal  outline,  with  sharp  or  rounded  angles,  according  to  the 
smaller  or  greater  quantity  of  Glisson's  capsule  contained  in  the 
liver.  Each  lobule  is  divided  upon  its  exterior  into  a  base  and  a 
capsular  surface.  The  base  corresponds  with  one  extremity  of  the 
lobule,  is  flattened,  and  rests  upon  an  hepatic  vein,  which  is  thence 
named  sublobalar.     The  capsular  surface  includes  the  rest  of  the 


544 


LOBULES  OF  THE  LIVER. 


periphery  of  the  lobule,  and  has  received  its  designation  from  being 
enclosed  in  a  cellular  capsule  derived  from  the  capsule  of  Glisson. 
In  the  centre  of  each  lobule  is  a  small  vein,  the  intralobular,  which 
is  formed  by  the  convergence  of  six  or  eight  minute  venules  from 
the  rounded  processes  situated  upon  the  surface.  The  intralobular 
vein  thus  constituted  takes  its  course  through  the  centre  of  the  lon- 
gitudinal axis  of  the  lobule,  pierces  the  middle  of  its  base,  and 
opens  into  the  sublobular  vein.  The  circumference  of  the  lobule, 
with  the  exception  of  its  base,  which  is  always  closely  attached  to 
a  sublobular  vein,  is  connected  by  means  of  its  cellular  capsule  with 
the  capsular  surface  of  surrounding  lobules.  The  cellular  interval 
between  the  lobules  is  the  interlobular  fissure,  and  the  angular  inter- 
stices formed  by  the  apposition  of  several  lobules  are  the  interlobular 
spaces. 

Fig.  186. 


The  lobules  of  the  centre  of  the  liver  are  angular,  and  somewhat 
smaller  than  those  of  the  surface,  from  the  greater  compression  to 
which  they  are  submitted.  The  superficial  lobules  are  incomplete, 
and  give  to  the  surface  of  the  organ  the  appearance,  and  all  the 
advantages  resulting  from  an  examination  of  a  transverse  section,  j 

"Each  lobule  is  composed  of  a  plexus  of  biliary  ducts,  of  a  venous 
plexus  formed  by  branches  of  the  portal  vein,  of  a  branch  (intra- 
lobular), of  an  hepatic  vein,  and  of  minute  arteries ;  nerves  and 
absorbents,  it  is  to  be  presumed,  also  enter  into  their  formation,  but 
cannot  be  traced  into  them."  "  Examined  with  the  microscope,  a 
lobule  is  apparently  composed  of  numerous  minute  bodies  of  a  yel- 
lowish colour,  and  of  various  forms,  connected  with  each  other  by 
vessels.  These  minute  bodies  are  the  acini  of  Malpighi."  "  If  an 
uninjected  lobule  be  examined  and  contrasted  with  an  injected 
lobule,   it  will  be  found  that  the  acini  of  Malpighi  in  the  former 

Fig.  186.  The  lobules  of  the  liver.  A.  The  lobules  as  they  are  seen  upon  the  surfiice 
of  the  liver,  or  wlien  divided  trnnsvcrHely.  I.  The  intralobular  vein  in  the  centre  of 
ea^  lobule.  2.  Tlie  interlobular  fissure.  3.  The  interlobular  space.  15.  A  long-itu- 
dinal  Koction  of  two  lobules.  1,  A  superficial  lobule,  terminating-  abruptly,  and  re- 
setnblinjr  a  section  at  its  extremity.  2.  A  deep  lobule,  showing'  tlie  foliated  appearance 
of  its  section.  3.  The  intralobular  vein,  with  its  converging  venules  ;  the  vein  lernii. 
nates  in  a  sublobular  vein.     4.  The  external,  or  capsular  surface  of  the  lobule. 


GLISSON  S  CAPSULE — PORTAL  VEIN. 


545 


are  identical  with  the  injected  lobular  biliary  plexus  in  the  latter, 
and  the  blood-vessels  in  both  will  be  easily  distinguished  from  the 
ducts." 


Fig.  187. 


Glisson's  capsule  is  the  cellu- 
lar tissue  which  envelopes  the 
hepatic  artery,  portal  vein,  and 
hepatic  duct,  during  their  pas- 
sage through  the  right  border  of 
the  lesser  omentum,  and  which 
continues  to  surround  them  to 
their  ultimate  distribution  in  the 
substance  of  the  lobules.  It 
forms  for  each  lobule  a  distinct 
capsule,  which  invests  it  on  all 
sides  with  the  exception  of  its 
base,  connects  all  the  lobules  to- 
gether, and  constitutes  the  pro- 
per capsule  of  the  entire  organ. 
But  "  Glisson's  capsule,"  ob- 
serves Mr.  Kiernan,  "  is  not 
mere  ceHular  tissue  ;  it  is  to  the  liver  what  the  pia  mater  is  to  the 
brain;  it  is  a  cellulo- vascular  membrane  in  which  the  vessels  divide 
and  subdivide  to  an  extreme  degree  of  minuteness ;  which  lines  the 
portal  canals,  forming  sheaths  for  the  larger  vessels  contained  in 
them,  and  a  web  in  which  the  smaller  vessels  ramify ;  which  enters 
the  interlobular  fissures,  and  with  the  vessels  forms  the  capsules  of 
the  lobules;  and  which  finally  enters  the  lobules,  and  with  the  blood- 
vessels expands  itself  over  the  secreting  biliary  ducts."  Hence 
arises  a  natural  division  of  the  capsule  into  three  portions,  avaginal, 
an  interlobular,  and  a  lobular  portion. 

The  vaginal  portion  is  that  which  invests  the  hepatic  artery, 
hepatic  duct,  and  portal 
vein,  in  the  portal  canals  ; 
in  the  larger  canals  it  com- 
pletely surrounds  these  ves- 
sels, but  in  the  smaller  is 
situated  only  on  that  side 
which  is  occupied  by  the 
artery  and  duct.  The  in- 
terlobular portion  occupies 
the  interlobular  fissures  and 
spaces,  and  the  lobular  por- 
tion forms  the  supporting 
tissue  to  the  substance  of  the  lobules. 

The  Portal  vein,  entering  the  liver  at  the  transverse  fissure,  rami- 


Fig.  188. 


vr 


A^^ 


Fig.  187.  Horizontal  section  of  three  superficial  lobules,  showing  the  two  principal 
syslems  of  bloodvessels. — (Kiernan.) 

Fig.  ]88.  Horizontal  section  of  two  superficial  lobules,  showing  interlobular  plexus 
of  biliary  ducts. — {Kieriian.) 

46* 


546  STRUCTURAL  ANATOMY  OF  THE  LIVER. 

fies  through  its  structure  in  canals  which  resemble,  by  their  surfaces, 
the  external  superficies  of  the  liver,  and  are  formed  by  the  capsular 
surfaces  of  the  lobules, — "all  their  canals  being,"  as  it  were,  "tubu- 
lar inflections  inwards  of  the  superficies  of  the  liver."  These  are 
the  portal  canals,  and  contain,  besides  the  portal  vein  with  its  rami- 
fications, the  artery  and  duct  with  their  branches. 

In  the  larger  canals,  the  vessels  are  separated  from  the  parietes 
of  the  cavity  by  a  web  of  Glisson's  capsule;  but,  in  the  smaller,  the 
portal  vein  is  in  contact  with  the  surface  of  the  canal  for  about  two- 
thirds  of  its  cylinder,  the  opposite  third  being  in  relation  with  the 
artery  and  duct  and  their  investing  capsule.  If,  therefore,  the  portal 
vein  were  laid  open  by  a  longitudinal  incision  in  one  of  these  smaller 
canals,  the  coats  being  transparent,  the  outline  of  the  lobules,  bounded 
by  their  interlobular  fissures,  would  be  as  distinctly  seen  as  upon 
the  external  surface  of  the  liver,  and  the  smaller  venous  branches 
woljld  be  observed  entering  the  interlobular  spaces. 

The  branches  of  the  portal  vein  are,  the  vaginal,  interlobular,  and 
lobular.  The  vaginal  branches  are  those  which,  being  given  off  in 
the  portal  canals,  have  to  pass  through  the  sheath  (vagina)  of  Glis- 
son's capsule,  previously  to  entering  the  interlobular  spaces.  In 
this  course  they  form  an  intricate  plexus,  the  vaginal  jylexus,  which, 
depending  for  its  existence  on  the  capsule  of  Glisson,  necessarily 
surrounds  the  vessels,  as  does  that  capsule  in  the  larger  canals,  and 
occupies  the  capsular  side  only  in  the  smaller  canals.  The  interlo- 
bular branches  are  given  oflf  from  the  vaginal  portal  plexus  where 
it  exists,  and  directly  from  the  portal  veins,  in  that  part  of  the 
smaller  canals  where  the  coats  of  the  vein  are  in  contact  with  the 
walls  of  the  canal.  They  then  enter  the  interlobular  spaces  and 
divide  into  branches,  which  cover  with  their  ramifications  every 
part  of  the  surface  of  the  lobules  with  the  exception  of  their  bases, 
and  those  extremities  of  the  superficial  lobules  which  appear  upon 
the  surfaces  of  the  liver.  The  interlobular  veins  communicate 
freely  with  each  other,  and  with  the  corresponding  veins  of  adjoin- 
ing fissures,  and  establish  a  general  portal  anastomosis  throughout 
the  entire  liver.  The  lobular  branches  are  derived  from  the  interlo- 
bular veins  ;  they  form  a  plexus  within  each  lobule,  and  converge 
from  the  circumference  towards  the  centre,  where  they  terminate 
in  the  minute  radicles  of  the  intralobular  portal  vein.  This  plexus, 
interposed  between  the  interlobular  portal  veins  and  the  intralobular 
hepatic  vein,  constitutes  the  venous  part  of  the  lobule,  and  rnay  be 
called  the  lobular  venous  'plexus.  The  irregular  islets  of  the  substance 
of  the  lobules,  seen  between  the  meshes  of  this  plexus  by  means  of 
the  microscope,  are  the  acini  of  Malpighi,  and  are  shown  by  Mr. 
Kiernan  to  be  portions  of  the  lobular  biliary  plexus. 

The  portal  vein  returns  the  venous  blood  from  the  chylopoietic 
viscera,  to  be  circulated  through  the  lobules;  it  also  receives  the 
venous  blood  which  results  from  tiie  distribution  of  the  hepatic 
artery. 

The  Hepatic  duct,  entering  the  liver  at  the  transverse  fissure, 


'  kiernan's  researches.  547 

divides  into  branches,  which  ramify  through  the  portal  canals,  with 
the  portal  vein  and  hepatic  artery,  to  terminate  in  the  substance  of 
the  lobules.  Its  branches,  like  those  of  the  portal  vein,  are  vaginal, 
interlobular,  and  lobular. 

The  Vaginal  branches  ramify  through  the  capsule  of  Glisson,  and 
form  a  vaginal  biliary  plexus,  which,  like  the  vaginal  portal  plexus, 
surrounds  tl)e  vessels  in  the  large  canals,  but  is  deficient  on  that  side 
of  the  smaller  canals  near  which  the  duct  is  placed.  The  branches 
given  off"  by  the  vaginal  biliary  plexus  are  interlobular  and  lobular. 
The  interlobular  branches  proceed  from  the  vaginal  biliary  plexus 
where  it  exists,  and  directly  from  the  hepatic  duct  on  that  side  of 
the  smaller  canals  against  which  the  duct  is  placed.  They  enter 
the  interlobular  spaces,  and  ramify  upon  the  capsular  surface  of  the 
lobules,  in  the  interlobular  fissures,  where  they  communicate  freely 
with  each  other.  The  lobular  ducts  are  derived  chiefly  from  the 
interlobular ;  but  to  those  lobules  forming  the  walls  of  the  portal 
canals,  they  pass  directly  from  the  vaginal  plexus.  They  enter  the 
lobule  and  form  a  plexus  in  its  interior,  the  lobular  biliary  plexus, 
which  constitutes  the  principal  part  of  the  substance  of  the  lobule. 
The  ducts  terminate  either  in  loops  or  in  cfecal  extremities. 

The  coats  of  the  ducts  are  very  vascular,  and  supplied  with  a 
number  of  mucous  follicles,  which  are  distributed  irregularly  in  the 
larger,  but  are  arranged  in  tvi'o  parallel  longitudinal  rows  in  the 
smaller  ducts. 

The  Hepatic  artery  enters  the  liver  with  the  portal  vein  and 
hepatic  duct,  and  ramifies  with  those  vessels  through  the  portal 
canals.  Its  branches  are  the  vaginal,  interlobular,  and  lobular.  The 
vaginal  branches,  like  those  of  the  portal  vein  and  hepatic  duct, 
form  a  vaginal  plexus,  which  exists  throughout  the  whole  extent  of 
the  portal  canals,  with  the  exception  of  that  side  of  the  smaller 
canals  which  corresponds  with  the  artery.  The  interlobular  branches, 
arising  from  the  vaginal  plexus  and  from  the  parietal  side  of  the 
artery  in  the  smaller  canals,  ramify  through  the  interlobular  fis- 
sures, and  are  principally  distributed  to  the  coats  of  the  interlobular 
ducts. 

"  From  the  superficial  interlobular  fissures  small  arteries  emerge, 
and  ramify  in  the  proper  capsule,  on  the  convex  and  concave  surface 
of  the  liver,  and  in  the  ligaments.  These  are  the  capsular  arteries^ 
Where  the  capsule  is  well  developed,  "  these  vessels  cover  the  sur- 
faces of  the  liver  with  a  beautiful  plexus,"  and  "anastomose  with 
branches  of  the  phrenic,  internal  mammary,  and  supra-renal  arte- 
ries," and  with  the  epigastric. 

The  Lobular  branches,  extremely  mioute  and  few  in  number,  are 
the  nutrient  vessels  of  the  lobules,  and  terminate  in  the  lobular 
venous  plexus. 

All  the  venous  blood  resulting  from  the  distribution  of  the  hepatic 
artery,  even  that  from  the  vasa  vasorum  of  the  hepatic  veins,  is  re- 
turned into  the  portal  vein. 

The  Hepatic  veins  commence  in  the  substance  of  each  lobule  by 


548  STRUCTCEAI.  ANATOMY  OF  THE  LIVER. 

minute  venules,  which  receive  the  blood  from  the  lobular  venous 
plexus,  and  converge  to  form  the  intralobular  vein.  The  intralobu- 
lar vein  passes  through  the  central  axis  of  the  lobule,  and  through 
the  middle  of  its  base,  to  terminate  in  a  subJobular  vein;  and  the 
union  of  the  sublobular  veins  constitutes  the  hepatic  trunks,  which 
terminate  in  the  inferior  vena  cava.  The  hepatic  venous  system 
consists,  therefore,  of  three  sets  of  vessels ;  intralobular  veins,  sub- 
lobular veins,  and  hepatic  trunks. 

The  Sublobular  veins  are  contained  in  canals  formed  solely  by  the 
bases  of  tlie  lobules,  with  which,  from  the  absence  of  Glisson's  cap- 
sule, they  are  in  immediate  contact.  Their  coats  are  thin  and  trans- 
parent ;  and  if  they  be  laid  open  by  a  longitudinal  incision,  the 
bases  of  the  lobules  will  be  distinctly  seen,  separated  by  interlobular 
fissures,  and  perforated  through  the  centre  by  the  opening  of  the 
intralobular  vein. 

The  Hepatic  trunks  are  formed  by  the  union  of  the  sublobular 
veins ;  they  are  contained  in  canals  (hepatic  venous)  similar  in 
structure  to  the  portal  canals,  and  lined  by  a  prolongation  of  the 
proper  capsule.  They  proceed  from  before  backwards,  and  termi- 
nate by  two  large  openings,  corresponding  to  the  right  and  left  lobe 
of  the  liver  in  the  inferior  vena  cava. 

It  is  to  Kiernan  that  anatomical  science  is  indebted  for  the  clear, 
distinct,  and  intelligible  idea  of  the  structure  of  this  most  compli- 
cated organ,  which  has  been  furnished  by  the  researches  of  that 
anatomist.  To  value  this  knowledge  as  it  deserves,  we  have  but  to 
reflect  upon  the  unsuccessful,  though  not  fruitless,  labours  of  those 
great  discoverers  in  structural  anatomy,  Malpighi  and  Ruysch,  upon 
the  same  subject,  and  the  strange  misconceptions  of  modern  authors, 
among  whom  Miiller  and  Cruveilhier  occupy  so  conspicuous  a  place. 
It  is  not,  however,  in  an  anatomical,  or  even  a  physiological  point 
of  view  merely,  that  we  have  to  admire  these  discoveries;  for  in 
their  practical  application  to  the  elucidation  of  pathological  appear- 
ances, and  the  explanation  of  the  phenomena  of  disease,  they  are 
still  more  interesting. 

Summary. — The  liver  has  been  shown  to  be  composed  oi  lobules ; 
the  lobules  (excepting  at  their  bases)  are  invested  and  connected 
together,  the  vessels  supported,  and  the  whole  organ  enclosed  by 
GHsson's  capsule;  and  they  are  so  arranged,  that  the  base  of  every 
lobule  in  the  liver  is  in  contact  with  an  hepatic  vein  (sublobular). 

The  Portal  vein  distributes  its  numberless  branches  through  portal 
canals,  which  are  channeled  through  every  part  of  the  organ  ;  it 
brings  the  returning  blood  from  the  chylopoietic  viscera ;  it  collects 
also  the  venous  blood  from  the  ultimate  ramifications  of  the  hepatic 
artery  in  the  liver  itself.  It  gives  ofl"  branches  in  the  canals,  which 
fire  called  vaginal,  and  form  a  venous  vaginal  plexus ;  these  give 
off  interlobular  brandies,  and  the  latter  enter  the  lobules  and  form 
lobular  venous  plexuses,  from  the  blood  circulating  in  which  the  bile 
is  secreted. 

The  Bile  in  the  lobule  is  received  by  a  network  of  minute  ducts 


STRUCTURAL  ANATOMY  OF  THE  LIVER.  549 

the  lobular  biliary  -plexus;  it  is  conveyed  from  the  lobule  inio  the 
interlobular  ducts;  it  is  thence  poured  into  the  biliary  vagival  plexus 
of  the  portal  canals,  and  thence  into  the  excreting  ducts,  by  which 
it  is  carried  to  the  duodenum  and  gall-bladder,  after  being  mingled 
in  its  course  with  the  mucous  secretion  from  the  numberless  muci- 
parous follicles  in  the  walls  of  the  ducts. 

The  Hepatic  artery  distributes  branches  through  every  portal 
canal;  gives  o^  vaginal  branches  which  form  a  vaginal  hepatic 
plexus,  from  which  the  interlobular  branches  arise,  and  these  latter 
terminate  ultimately  in  the  lobular  venous  plexuses  of  the  portal 
vein.  The  artery  ramifies  abundantly  in  the  coats  of  the  hepatic 
ducts,  enabling  them  to  provide  their  mucous  secretion  ;  and  sup- 
plies the  vasa  vasorum  of  the  portal  and  hepatic  veins,  and  the  nu- 
trient vessels  of  the  entire  organ. 

The  Hepatic  veins  commence  in  the  centre  of  each  lobule  by 
minute  radicles,  which  collect  the  impure  blood  from  the  lobular 
venous  plexus  and  convey  it  into  the  intralobular  veins;  these  open 
into  the  sublobular  veins,  and  the  sublobular  veins  unite  to  form  the 
large  hepatic  trunks  by  which  the  blood  is  conveyed  into  the  vena 
cava. 

The  physiological  deduction  arising  out  of  this  anatomical  ar- 
rangement is,  that  the  bile  is  loholly  secreted  from  venous  blood,  and 
not  from  a  mixed  venous  and  arterial  blood,  as  is  believed  by 
Miiller ;  for  although  the  portal  vein  receives  its  blood  from  two 
sources,  viz.  from  the  chylopoietic  viscera  and  from  the  capillaries 
of  the  hepatic  artery,  yet  the  very  fact  of  the  blood  of  the  latter 
vessel  having  passed  through  its  capillaries  into  the  portal  vein,  or 
in  extremely  small  quantity  into  the  capillary  network  of  the  lobular 
venous  plexus,  is  sufficient  to  establish  its  venous  character.* 

The  pathological  deductions  depend  upon  the  following  facts: — 
Each  lobule  is  a  perfect  gland ;  of  uniform  structure,  of  uniform 
colour,  and  possessing  the  same  degree  of  vascularity  throughout. 
It  is  the  seat  of  a  double  venous  circulation,  the  vessels  of  the  one 
{hepatic)  being  situated  in  the  centre  of  the  lobule,  and  those  of  the 
other  {portal)  in  the  circumference.  Now  the  colour  of  the  lobule, 
as  of  the  entire  liver,  depends  chiefly  upon  the  proportion  of  blood 
contained  within  these  two  sets  of  vessels ;  and  so  long  as  the  cir- 
culation is  natural  the  colour  will  be  uniform.  But  the  instant  that 
any  cause  is  developed  which  shall  interfere  with  the  free  circula- 
tion of  either,  there  will  be  an  immediate  diversity  in  the  colour  of 
the  lobule. 

Thus,  if  there  be  any  impediment  to  the  free  circulation  of  the 
venous  blood  through  the  heart  or  lung?,  the  circulation  in  the 
hepatic  veins  will  be  retarded,  and  the  sublobular  and  the  intra- 
lobular veins  will  become  congested,  giving  rise  to  a  more  or  less 
extensive  redness  in  the  centre  of  each  of  the  lobules,  while  the  mar- 
ginal or  non-congested  portion  presents  a  distinct  border  of  a  yel- 

*  For  arg-uments  upon  this  contested  question,  see  the  article  "Liver,"  in  the  "Cyclo- 
paedia  of  Anatomy  and  Physiology,"  edited  by  Dr.  Todd. 


550  GALL-BLADDER. 

lowish  white,  yellow,  or  green  colour,  according  to  the  quantity 
and  quality  of  the  bile  it  may  contain.  "  This  is  'passive  congestion' 
of  the  liver,  the  usual  and  natural  state  of  the  organ  after  death ;" 
and,  as  it  commences  with  the  hepatic  vein,  it  may  be  called  the 
first  stage  of  hepatic-venous  congestion. 

But  if  .he  causes  which  produced  this  state  of  congestion  con- 
tinue, or  be  from  the  beginning  of  a  more  active  kind,  the  conges- 
tion will  extend  through  the  lobular  venous  plexuses  "  into  those 
branches  of  the  portal  vein  situated  in  the  interlobular  fissures,  but 
not  to  those  in  the  spaces,  which,  being  larger,  and  giving  origin  to 
those  in  the  fissures,  are  the  last  to  be  congested."  In  this  second 
stage  the  liver  has  a  mottled  appearance,  the  non-congested  sub- 
stance is  arranged  in  isolated,  circular,  and  ramose  patches,  in  the 
centres  of  which  the  spaces  and  part  of  the  fissures  are  seen.  This 
is  an  extended  degree  of  hepatic-venous  congestion ;  it  is  "  active 
congestion"  of  the  liver,  and  very  commonly  attends  diseases  of  the 
heart  and  lungs. 

There  is  another  form  of  partial  venous  congestion  which  com- 
mences in  the  portal  vein ;  this  is,  therefore,  portal  venous  congestion. 
It  is  of  very  rare  occurrence,  and  Mr.  Kiernan  has  observed  it  in 
children  only.  "In  this  form  the  congested  substance  never  assumes 
the  deep  red  colour  which  characterizes  hepatic  venous  conges- 
tion ;  the  interlobular  fissures  and  spaces,  and  the  marginal  portions 
of  the  lobules  are  of  a  deeper  colour  than  usual ;  the  congested 
substance  is  continuous  and  cortical,  the  non-congested  substance 
being  medullary,  and  occupying  the  centres  of  the  lobules.  The 
second  stage  of  hepatic  venous  congestion,  in  which  the  congested 
substance  appears,  but  is  not  cortical,  may  be  easily  confounded 
with  portal  venous  congestion. 

These  are  instances  of  partial  congestion,  but  there  is  sometimes 
general  congestion  of  the  organ.  "In  general  congestion  the  whole 
liver  is  of  a  red  colour,  but  the  central  portions  of  the  lobules  are 
usually  of  a  deeper  hue  than  the  marginal  portions." 

GALL-BLADDER. 

The  gall-bladder  is  the  reservoir  for  the  bile;  it  is  a  pyriform  sac 
situated  in  a  fossa,  upon  the  under  surface  of  the  right  lobe  of  the 
liver,  and  extending  from  the  right  extremity  of  the  transverse  fis- 
sure to  its  free  margin.  It  is  divided  into  a  body,  fundus,  and  neck  ; 
the  fundus  or  broad  extremity  in  the  natural  position  of  the  liver  is 
placed  downwards,  and  frequently  projects  beyond  the  free  margin 
of  the  liver,  while  the  neck,  small  and  constricted,  is  directed 
upwards.  This  sac  is  composed  of  three  coats,  serous,  fibrous,  and 
mucous.  The  serous  coat  is  partial,  is  derived  from  the  peritoneum, 
and  covers  that  side  only  which  is  unattached  to  the  liver.  The 
middle  or  fihrous  coat  is  a  thin  but  strong  cellulo-fibrous  layer,  inter- 
mingled with  tendinous  fibres.  Ii  is  connected  on  one  side  to  the 
liver,  and  on  the  other  to  the  peritoneum.  The  internal  or  mucous 
coat  is  but  loosely  connected   with  the  fihrous  layer;  it  is  every 


THE  PANCREAS.  551 

where  raised  into  minute  rugss  which  give  it  a  beautifully  reticu- 
lated appearance,  and  forms  at  the  neck  of  the  sac  a  spiral  valve. 

It  is  continuous  through  the  hepatic  duct  with  the  mucous  mem- 
brane lining  all  the  ducts  of  the  liver,  and  through  the  ductus  com- 
munis choledochus,  with  the  mucous  membrane  of  the  alimentary 
canal. 

The  Biliary  ducts  are, — the  ductus  communis  choledochus,  the 
cystic  and  the  hepatic  duct. 

The  Ductus  commiuiis  choledochus  (x°'^''i  bilis,  Sixop-ai  recipio)  is 
the  common  excretory  duct  of  the  liver  and  gall-bladder ;  it  is  about 
three  inches  in  length,  and  commences  upon  the  papilla,  situated  on 
the  inner  side  of  the  cylinder  of  the  perpendicular  portion  of  the 
duodenum.  Passing  obliquely  between  the  mucous  and  muscular 
coats,  it  ascends  behind  the  duodenum,  and  through  the  right  border 
of  the  lesser  omentum  ;  and  divides  into  tv/o  branches,  the  cystic 
duct  and  the  hepatic  duct.  It  is  constricted  at  its  commencement 
in  the  duodenum,  and  becomes  dilated  in  its  progress  upwards. 

The  Cystic  duct,  about  an  inch  in  length,  passes  outwards  to  the 
neck  of  the  gallbladder,  with  which  it  is  continuous. 

The  Hepatic  duct  continues  onwards  to  the  transverse  fissure  of 
the  liver,  and  divides  into  two  branches,  which  ramify  through  the 
portal  canals  to  every  part  of  the  liver. 

The  coats  of  the  hepatic  ducts  are  an  external  or  fibrous,  and  an 
internal  or  mucous. 

The  external  coat  is  composed  of  a  contractile  fibrous  tissue, 
which  is  probably  muscular;  but  its  muscularity  has  not  yet  been 
demonstrated  in  the  human  subject.  The  mucous  coat  is  continuous 
on  the  one  hand  with  the  lining  membrane  of  the  hepatic  ducts  and 
gall-bladder,  and  on  the  other  with  that  of  the  duodenum. 

Vessels  and  Nerves. — The  gall-bladder  is  supplied  with  blood  by 
the  cystic  artery,  a  branch  of  the  hepatic.  Its  veins  return  their 
blood  into  the  portal  vein.  The  nerves  are  derived  from  the  hepatic 
plexus. 

THE    PANCREAS. 

The  Pancreas  is  a  long,  flattened,  conglomerate  gland,  analogous 
to  the  salivary  glands.  It  is  about  six  indies  in  length,  and  between 
three  or  four  ounces  in  weight,  and  is  situated  transversely  across 
the  posterior  wall  of  the  abdomen,  behind  the  stomach,  and  resting 
upon  the  aorta,  vena  portse,  inferior  vena  cava,  the  origin  of  the 
superior  mesenteric  artery,  and  the  left  kidney  and  supra-renal 
capsule ;  opposite  to  the  first  and  second  lumbar  vertebras.  It  is 
divided  into  a  body,  a  greater,  and  a  smaller  extremity;  the  great 
end  or  head  is  placed  towards  the  right,  and  is  surrounded  by  the 
curve  of  the  duodenum  ;  the  lesser  end  extends  to  the  left  as  far  as 
the  spleen.  The  anterior  surface  of  the  bod}^  of  the  pancreas  is 
covered  by  the  ascending  posterior  layer  of  the  peritoneum  and  is 
in  relation  with  the  stomach,  the  first  portion  of  the  duodenum  and 
the  commencement  of  the  transverse  arch  of  the  colon.     The  pos- 


552  THE  SPLEEN. 

terior  surface  is  grooved  for  tfie  splenic  vein,  and  tunneled  ,by  a 
complete  canal  for  the  superior  mesenteric  and  portal  vein,  and 
for  the.  superior  mesenteric  artery.  The  upper  border  presents  a 
deep  groove,  sometimes  a  canal  for  the  splenic  artery  and  vein, 
and  is  in  relation  with  the  oblique  portion  of  the  duodenum,  the 
lobus  Spigelii,  and  the  coeliac  axis.  And  the  lower  border  is  sepa- 
rated from  the  transverse  portion  of  the  duodenum  by  the  superior 
mesenteric  artery  and  vein.  Upon  the  posterior  part, of  the  head 
of  the  pancreas  is  a  lobular  fold  of  the  gland  which  completes  the 
canal  of  the  superior  mesenteric  vessels,  and  is  called  the  lesser 
pancreas. 

In  structure  it  is  composed  of  reddish-yellow  angular  lobules  ; 
these  consist  of  smaller  lobules,  and  the  latter  are  made  up  of  the 
arborescent  ramifications  of  minute  ducts,  terminating  in  ccecal 
pouches. 

The  pancreatic  duct  commences  at  the  papilla  upon  the  inner  and 
posterior  surface  of  the  perpendicular  portion  of  the  duodenum  by  a 
small  dilatation  which  is  common  to  it  and  to  the  ductus  communis 
choledochus,  and  passing  obliquely  between  the  mucous  and  muscu- 
lar coats  runs  from  right  to  left  through  the  middle  of  the  gland, 
lying  nearer  to  its  anterior  than  to  its  posterior  surface.  At  about 
the  commencement  of  the  apicial  third  of  its  course  it  divides  into 
two  parallel  terminal  branches.  It  gives  off  numerous  small 
branches,  which  are  distributed  through  the  lobules,  and  constitute 
with  the  latter  the  substances  of  the  gland.  The  duct  which  re- 
ceives the  secretion  from  the  lesser  pancreas  is  called  the  ductus 
pancreaticus  minor;  it  opens  into  the  principal  duct  near  to  the 
duodenum,  and  sometimes  passes  separately  into  that  intestine.  As 
a  variety,  two  pancreatic  ducts  are  occasionally  met  with. 

Vessels  and  Nerves. — The  arteries  of  the  pancreas  are  branches 
of  the  splenic,  hepatic,  and  superior  mesenteric  ;  the  veins  open  into 
the  splenic  vein  ;  the  lymphatics  terminate  in  the  lumbar  glands. 
The  nerves  are  filaments  of  the  splenic  plexus. 

THE    SPLEEPT. 

The  spleen  is  an  oblong  flattened  organ  of  a  dark  bluish-red 
colour,  situated  in  the  left  hypochondriac  region.  It  is  very  variable 
in  size  and  weight,  spongy  and  vascular  in  texture  and  exceedingly 
friable.  The  external  surface  is  convex,  the  internal  slightly  con- 
cave, indented  along  the  middle  line,  and  pierced  by  several  large 
and  irregular  openings  for  the  entrance  and  exit  of  vessels;  this  is 
the  hilus  lienis.  The  upper  extremity  is  somewhat  larger  than  the 
lower,  and  rounded ;  the  inferior  is  flattened ;  the  posterior  border 
is  obtuse;  the  anterior  is  sharp  and  marked  by  several  notches. 
The  spleen  is  in  relation  by  its  external  or  convex  surface  with  the 
diaphragm,  which  separates  it  from  the  ninth,  tenth,  and  eleventh 
ribs;  by  its  concave  surface  with  the  great  end  of  the  stomach,  the 
extremity  of  the  pancreas,  the  gastro-splenic  omentum  with  its  ves- 
sels, the  left  kidney  and  supra-renal  capsule,  and  with  the  left  crus 


CAPSUL.E  RENALES.  553 

of  the  diaphragm  ;  by  its  npperend  with  the  diaphragm,  and  some- 
times with  the  extremity  of  the  left  lobe  of  the  liver,  and  by  its  lower 
end  with  the  left  extremity  of  the  transverse  arch  of  the  colon.  It 
is  connected  to  the  stomach  by  the  gastro-splenic  omentum  and  by 
the  vessels  contained  in  that  duplicature.  A  second  spleen  (lien 
succenturiatus)  is  sometimes  found  appended  to  one  of  the  branches 
of  the  splenic  artery,  near  to  the  great  end  of  the  stomach;  when  it 
exists,  it  is  round  and  of  very  small  size,  rarely  larger  than  a  hazel- 
nut. I  have  seen  two  and  even  three  of  these  bodies.  The  spleen 
is  invested  by  the  peritoneum  and  by  a  tunica  propria  of  yellow 
elastic  tissue,  which  enables  it  to  yield  to  the  greater  or  less  disten- 
sion of  its  vessels.  The  elastic  tunic  forms  sheaths  for  the  vessels 
in  their  ramifications  through  the  organ,  and  from  these  sheaths 
small  fibrous  bands  are  given  off  in  all  directions,  which  become 
attached  to  the  internal  surface  of  the  elastic  tunic,  and  constitute 
the  cellular  framework  of  the  spleen.  The  substance  occupying 
the  interspaces  of  this  tissue  is  soft  and  granular,  and  of  a  bright 
red  colour;  in  animals  it  is  interspersed  with  small,  white,  soft 
corpuscules. 

Vessels  and  Nerves. — The  Splenic  artery  is  of  a  very  large  size 
in  proportion  to  the  bulk  of  the  spleen  ;  it  is  a  division  of  the  coeliac 
axis.  The  branches  which  enter  the  spleen  are  distributed  to  dis- 
tinct sections  of  the  organ,  and  anastomose  very  sparingly  with 
each  other.  The  veins  by  their  numerous  dilatations  constitute  the 
principal  part  of  the  bulk  of  the  spleen ;  they  pour  their  blood  into 
the  splenic  vein,  which  is  one  of  the  two  great  formative  trunks  of 
the  portal  vein.  The  lymphatics  are  remarkable  for  their  number 
and  large  size,  they  terminate  in  the  lumbar  glands.  The  nerves 
are  the  splenic  plexus,  derived  from  the  solar  plexus. 

THE   SUPRA-RENAL   CAPSULES. 

The  supra-renal  capsules  are  two  small  yellowish  and  flattened 
bodies  surmounting  the  kidneys,  and  inclining  inwards  towards  the 
vertebral  column.  The  right  is  somewhat  three-cornered  in  shape, 
the  left  more  semilunar;  they  are  connected  to  the  kidneys  by  the 
common  investing  cellular  tissue,  and  each  capsule  is  marked  upon 
its  anterior  surface  by  a  fissure  which  appears  to  divide  it  into  two 
lobes.  The  right  supra-renal  capsule  is  closely  adherent  to  the  pos- 
terior and  under  surface  of  the  liver,  and  the  left  lies  in  contact  with 
the  pancreas.  Both  capsules  rest  upon  the  crura  of  the  diaphragm 
on  a  level  with  the  tenth  dorsal  vertebra,  while  by  their  inner  border 
they  are  in  relation  with  the  great  splanchnic  nerve,  and  with  the 
semilunar  ganglion.  They  are  larger  in  the  foetus  than  in  the  adult, 
and  appear  to  perform  some  office  connected  with  embryonic  life. 
The  anatomy  of  these  organs  in  the  foetus  will  be  found  in  the  suc- 
ceeding chapter. 

In  structure  they  are  composed  of  two  substances,  cortical  and 
medullary.  The  cortical  substance  is  of  a  yellowish  colour,  and 
consists  of  straight  parallel  fibres  placed  perpendicularlv  side  by 

47 


654  THE  KIDNEYS. 

side.  The  medullary  substance  is  generally  of  a  dark  brown 
colour,  double  the  quantity  of  the  yellow  substance,  soft  in  texture, 
and  contains  within  its  centre  the  trunk  of  a  large  vein — the  vena 
supra-renalis.  It  is  the  large  size  of  this  vein  that  gives  to  the  fresh 
supra-renal  capsule  the  appearance  of  a  central  cavity;  the  dark- 
coloured  pulpy  or  fluid  contents  of  the  capsule,  at  a  certain  period 
after  death,  are  produced  by  softening  of  the  medullary  substance. 
Dr.  Nagel*  has  shown,  by  his  injections  and  microscopic  examina- 
tions, that  the  appearance  of  straight  fibres  in  the  cortical  substance 
is  caused  by  the  direction  of  a  plexus  of  capillary  vessels.  Of  the 
numerous  minute  arteries,  supplying  the  supra-renal  capsule,  he 
says,  the  greater  number  enter  the  cortical  substance  at  every  point 
of  its  surface,  and,  after  proceeding  for  scarcely  half  a  line  in  its 
substance,  divide  into  a  plexus  of  straight  capillary  vessels.  Some 
few  of  the  small  arteries  pierce  the  cortical  layer  and  give  off  seve- 
ral branches  in  the  medullary  substance,  which  proceed  in  different 
directions,  and  re-enter  the  conical  layer  to  divide  into  a  capillary 
plexus  in  a  similar  manner  with  the  preceding.  From  the  capillary 
plexus,  composing  the  cortical  layer,  the  blood  is  received  by  nume- 
rous small  veins  which  form  a  venous  plexus  in  the  medullary  sub- 
stance, and  terminate  at  acute  angles  in  the  large  central  vein. 

Vessels  and  JVerves. — The  supra-renal  arteries  are  derived  from 
the  aorta,  from  the  renal,  and  from  the  phrenic  arteries ;  they  are 
remarkable  for  the  innumerable  minute  arteries  into  which  they 
divide  previously  to  entering  the  capsule.  The  supra-renal  vein 
collecting  the  blood  from  the  medullary  venous  plexus  and  receiv- 
ing the  several  branches  which  pierce  the  cortical  layer,  opens 
directly  into  the  vena  cava  on  the  right  side,  and  into  the  renal 
vein  on  the  left. 

The  Lymphatics  are  large  and  very  numerous ;  they  terminate 
in  the  lumbar  glands.  The  nerves  are  derived  from  the  renal  and 
from  the  phrenic  plexus. 

THE    KIDNEYS. 

The  kidneys,  the  secreting  organs  of  the  urine,  are  situated  in 
the  lumbar  regions  behind  the  peritoneum,  and  on  each  side  of  the 
vertebral  column,  which  they  approach  by  their  upper  extremities. 
Each  kidney  is  between  four  and  five  inches  in  length,  about  two 
inches  and  a  half  in  breadth,  and  somewhat  more  than  one  inch  in 
thickness;  and  weighs  between  three  and  five  ounces.  The  kidneys 
are  usually  enclosed  in  a  quantity  of  fat,  they  rest  upon  the  dia- 
phragm, upon  the  anterior  lamella  of  the  transversalis  muscle,  which 
separates  them  from  the  quadratus  lumborum,  and  upon  the  psoas 
magnus.  The  right  kidney  is  somewhat  lower  than  the  left,  from 
the  position  of  the  liver;  it  is  in  relation  by  its  anterior  surface  with 
the  liver  and  descending  portion  of  the  duodenum,  which  rest  upon 
it,  and  is  covered  in  by  the  ascending  colon  and  by  its  flexure.  The 

*  Mailer's  Archiv.  1836. 


STKUCTURE  OF  KIDNEYS. 


555 


Fiff.  189. 


left  kidney,  higher  than  the  right,  is  covered  in  front  by  the  great 
end  of  the  stomach,  by  the  spleen,  descending  colon  with  its  flexure, 
and  by  a  portion  of  the  small  intestines.  The  anterior  surface  of 
the  kidney  is  convex,  while  the  posterior  is  flat;  the  superior  ex- 
tremity is  in  relation  with  the  supra- renal  capsule;  the  convex 
border  is  turned  outwards  towards  the  parietes  of  the  abdomen ; 
and  the  concave  border  looks  inwards  towards  the  vertebral  column, 
and  is  excavated  by  a  deep  fissure — the  hilus  renalis — in  which  are 
situated  the  vessels  and  nerves  and  pelvis  of  the  kidney;  the  renal 
vein  being  the  most  anterior,  next  the  renal  artery,  and  lastly  the 
pelvis. 

The  kidney  is  dense  and  fragile  in  texture,  and  is  invested  by  a 
proper  fibrous  capsule,  which  is  easily  torn 
from  its  surface.  When  divided  by  a  longi- 
tudinal incision  carried  from  the  convex  to 
the  concave  border,  it  presents  in  its  interior 
two  structures,  an  external  or  vascular  (cor- 
tical), and  an  internal  or  tubular  (medullary) 
substance.  The  tubular  portion  is  formed 
of  pale  reddish-coloured  conical  bodies  cor- 
responding by  their  bases  with  the  vascular 
structure,  and  by  their  apices  with  the  hilus 
of  the  organ  ;  these  bodies  are  named  cones, 
and  are  from  eight  to  fifteen  in  number. 
The  vascular  portion  is  composed  of  blood- 
vessels, and  of  the  plexiform  convolutions 
of  uriniferous  tubuli,  and  not  only  forms 
the  surface  of  the  kidney,  but  dips  between 
the  cones  and  surrounds  them  nearly  to  their 
apices.  The  tubuli  uriniferi  communicate 
frequently  with  each  other  in  the  vascular  structure  of  the  kidney, 
and  terminate  in  anastomosing  loops  and  csecal  extremities.  They 
are  each  surrounded  by  a  fine  network  of  capillary  vessels.  When 
examined  with  a  lens  of  low  power,  a  multitude  of  small  globular 
bodies,  glomeruli  (corpora  Malpighiana)  are  seen  to  be  interspersed 
through  the  vascular  structure  of  the  organ,  and  to  be  connected  to 
the  minute  twigs  of  the  arteries.  They  are  about  y^o^h  of  an  inch 
in  diameter,  are  composed  of  an  aggregated  plexus  of  capillary 
vessels,  and  enclose  a  small  central  cavity,  the  use  of  which  is  as 
yet  unknown. 

The  Cones  are  composed  of  minute  straight  tubuli  uriniferi  of 
about  the  diameter  of  a  fine  hair;  they  divide  into  parallel  branches 
in  their  course,  and  commence  by  minute  openings  upon  the  apex 

Fi^.  189.  A  section  of  the  kidney,  surmounted  by  the  supra-renal  capsule  ;  the  swell- 
ings upon  the  surface  mark  the  original  constiUition  of  the  orsfan  by  distinct  lobes.  1. 
The  supra-renal  capsule.  D.  The  vascular  portion  of  the  kidney,  'i,  3.  Its  tubular 
portion,  consisting-  of  cones.  4,  4.  Two  of  the  papillae  projecting;  into  tiiin  correspond, 
ing  calices.  5,  5,  5.  The  three  infundibuli;  the  middle  5  is  situated  in  the  mouth  of  a 
calyx.     6.  The  pelvis.     7.  The  ureter. 


556 


MALE  PEIiVIS — CONTENTS. 


or  papilla  of  each  cone.  The  papillae  are  invested  by  mucous  mem- 
brane, which  is  continuous  with  the  lining  membrane  of  the  tubuli, 
and  forms  a  cup-like  pouch,  the  calyx,  around  each  papilla. 

The  calices  communicate  with  a  common  cavity  of  larger  size, 
situated  at  each  extremity,  and  in  the  middle  of  the  organ  ;  and 
these  three  cavities — the  infundibula — constitute  by  their  union  the 
large  membranous  sac,  which  occupies  the  hilus  renalis,  the  pelvis 
of  the  kidney. 

The  kidney  in  the  embryo  and  foetus  consists  of  lobules.  See  the 
anatomy  of  the  foetus  in  the  succeeding  chapter. 

Fiff.  190. 


The  Ureter  (ou^ov,  urine,  r-^fsiv,  to  keep),  the  excretory  duct  of  the 
kidney,  is  a  membranous  tube  of  about  the  diameter  of  a  goose-quill, 
and  nearly  eighteen  inches  in  length;  it  is  continuous  superiorly 
with  the  pelys  of  the  kidney,  and  is  constricted  inferiorly,  where  it 
lies  in  an  oblique  direction  between  the  muscular  and  mucous  coats 

Fi^.  190,  A  side  view  of  the  viscera  of  the  male  pelvis  in  situ.  The  right  side  of  the 
pelvis  has  been  removed  by  a  vertical  section  made  through  the  os  pubis  near  to  the 
symphysis;  and  another  through  the  middle  of  the  sacrum.  1.  The  divided  surface  of 
the  OS  pubis.  2.  The  divided  surface  of  the  sacrum.  3.  The  body  of  the  bladder.  4. 
Its  fundus;  from  the  apex  is  seen  passing  upwards  the  urachus.  5.  The  base  of  the 
bladder.  6.  The  ureter.  7.  The  neck  of  the  bladder.  8,  8.  The  pelvic  fascia ;  the 
fibres  immediately  above  7  are  given  off  from  the  pelvic  fascia  and  represent  the  an- 
terior ligaments  of  tiie  bladder.  9.  The  prostate  gland.  10.  The  membranous  portion 
of  the  urethra,  between  the  two  layers  of  the  deep  perineal  fascia.  1 1 .  The  deep  perineal 
fascia  formed  of  two  layers.  12.  One  of  Cowper's  glands  between  the  two  layers  of 
deep  perineal  fascia,  and  beneath  the  membranous  portion  of  the  urethra.  13.  The 
bulb  of  the  corpus  spongiosum.  14.  The  body  of  the  corpus  spongiosum.  15.  The 
right  crus  penis.  16.  The  upper  part  of  the  first  portion  of  the  rectum.  17.  The  recto- 
vesical fold  of  peritoneum.  18.  The  second  portion  of  the  rectum.  19.  The  right 
vchicula  seminalis.  20.  'I'he  vas  deferens.  21.  Tlie  rectum  covered  with  the  descend- 
ing layer  of  the  pelvic  fascia,  just  as  it  is  making  its  bend  backwards  to  constitute  the 
third  portion.  22.  A  part  of  the  levator  ani  mu.scle  investing  the  lower  part  of  the  rcc- 
tiun.  23.  The  external  spliinclcr  ani.  21.  Th(!  interval  between  the  deep  and  supcr- 
fix;idl  perineal  fascia  ;  they  are  seen  to  be  continuous  beneath  the  figure. 


THE  PELVIS  AND  BLADDER.  557 

of  the  base  of  the  bladder,  and  opens  upon  its  mucous  surface. 
Lying  along  the  posterior  wall  of  the  abdomen,  it  is  situated  behind 
the  peritoneum  and  is  crossed  by  the  spermatic  vessels ;  in  its  course 
downwards  it  rests  upon  the  anterior  surface  of  the  psoas,  and 
crosses  the  common  iliac  artery  and  vein,  and  then  the  external 
iliac  vessels.  Within  the  pelvis  it  crosses  the  umbilical  artery  and 
the  vas  deferens  in  the  male,  and  the  upper  part  of  the  vagina  in 
the  female.     There  are  sometimes  two  ureters  to  one  kidney. 

The  ureter,  the  pelvis,  the  infundibula,  and  the  calices  are  com- 
posed of  two  coats,  an  external  or  fibrous  coat,  the  tunica  propria; 
and  an  internal  mucous  coat,  which  is  continuous  with  the  mucous 
membrane  of  the  bladder  inferiorly,  and  with  the  lining  of  the 
tubuli  uriniferi  above. 

Vessels  and  Nerves. — The  renal  artery  is  derived  from  the  aorta ; 
it  divides  into  several  large  branches  before  entering  the  hilus. 
There  are  frequently  two.renal  arteries  and  sometimes  three. 

The  Veins  terminate  in  the  vena  cava  by  a  single  large  trunk  on 
each  side;  the  left  renal  vein  receiving  the  left  spermatic  vein. 
Injections  thrown  into  the  renal  artery  and  returning  by  the  vein, 
generally  make  their  way  into  those  vessels  by  rupture;  and  when 
the  injection  returns  by  the  tubuli  uriniferi,  it  aKvays  occurs  from 
the  bursting  of  the  capillary  vessels  of  the  ducts  into  their  cavities. 
The  lymphutic  vessels  terminate  in  the  lumbar  glands. 

The  Nerves  are  derived  from  the  renal  plexus,  which  is  formed 
partly  by  the  solar  plexus,  and  partly  by  the  lesser  splanchnic 
nerve.  The  renal  plexus  gives  branches  to  the  spermatic  plexus, 
and  branches  which  accompany  the  ureters:  hence  the  morbid 
sympathies  which  exist  between  the  kidney,  the  ureter,  and  the 
testicle;  and  by  the  communications  with  the  solar  plexus,  with 
the  stomach  and  diaphragm,  and  indeed  with  the  whole  system. 

THE    PELVIS. 

The  cavity  of  the  pelvis  is  that  portion  of  the  great  abdominal 
cavity  which  is  included  within  the  bones  of  the  pelvis,  below  the 
level  of  the  linea-ilio-pectinea  and  the  promontory  of  the  sacrum. 
It  is  bounded  by  the  cavity  of  the  abdomen  above,  and  by  the  peri- 
neum below  ;  its  internal  parietes  are  formed  in  front,  below,  and 
at  the  sides,  by  the  peritoneum,  pelvic  fascia,  levatores  ani  muscles, 
obturator  fasciee  and  muscles;  and  behind,  by  the  sacrum,  and 
sacral  plexus  of  nerves. 

The  Viscera  of  the  pelvis  in  the  male  are  the  urinary  bladder,  the 
prostate  gland,  vesiculae  seminales,  and  the  rectum. 

BLADDER. 

The  Bladder  is  an  oblong  membranous  viscus  of  an  ovoid  shape, 
situated  behind  the  os  pubis  and  in  front  of  the  rectum.  It  is  larger 
in  its  vertical  diameter  than  from  side  to  side;  and  its  long  axis  is 
directed  from  above,  obliquely  downwards  and  backwards.  It  is 
divided  into  body,  fundus,  base,  and  neck.     The  body  comprehends 

47* 


558  IIGAMENTS  OF  THE  BLADDER. 

the  middle  zone  of  the  organ ;  the  fundus,  its  upper  segment ;  the 
base,  the  lower  broad  extremity,  which  rests  upon  the  rectum  ;  and 
the  nech,  the  narrow  constricted  portion  which  is  appUed  against 
the  prostate  gland. 

This  organ  is  retained  in  its  place  by  ligaments  which  are  divided 
into  true  and  false;  the  true  ligaments  are  seven  in  number,  two 
anterior,  two  lateral,  two  umbilical,  and  the  urachus;  the  false  liga- 
ments are  folds  of  the  peritoneum,  and  are  four  in  number,  two 
anterior  and  two  posterior. 

The  Anterior  ligaments  are  formed  by  the  pelvic  fascia,  which 
passes  from  the  inner  surface  of  the  os  pubis,  on  each  side  of  the 
symphysis,  to  the  front  of  the  bladder. 

The  Lateral  ligaments  are  formed  by  the  reflection  of  the  pelvic 
fascia  from  the  levatores  ani  muscles,  upon  the  sides  of  the  base  of 
the  bladder. 

The  Umbilical  ligaments  are  the  fibrous  cords  which  result  from 
the  obliteration  of  the  umbilical  arteries  of  the  foetus;  they  pass 
forw^ards  on  each  side  of  the  fundus  of  the  bladder,  and  ascend 
beneath  the  peritoneum  to  the  umbilicus. 

The  Urachus  is  a  small  fibrous  cord  formed  by  the  obliteration 
of  a  tubular  canal  existing  in  the  embryo;  it  is  attached  to  the 
apex  of  the  bladder,  and  thence  ascends  to  the  umbilicus. 

The  False  ligaments  are  folds  of  peritoneum,  the  two  lateral  cor- 
respond with  the  passage  of  the  vasa  deferentia,  from  the  sides  of 
the  bladder  to  the  internal  abdominal  rings,  and  the  two  posterior 
with  the  course  of  the  umbilical  arteries,  to  the  fundus  of  the  organ. 

The  bladder  is  composed  of  three  coats,  an  external  or  serous 
coat,  a  muscular,  and  a  mucous  coat.  The  serous  coat  is  partial, 
and  derived  from  the  peritoneum,  which  invests  the  posterior  sur- 
face and  sides  of  the  bladder,  from  about  opposite  the  point  of  termi- 
nation of  the  two  ureters  to  its  summit,  whence  it  is  guided  to  the 
anterior  wall  of  the  abdomen  by  the  umbilical  ligaments  and  ura- 
chus. The  muscular  coat  consists  of  two  layers,  an  external  layer 
composed  of  longitudinal  fibres,  the  detrusor  urines ;  and  an  internal 
layer  of  oblique  and  transverse  fibres  irregularly  distributed.  The 
anterior  longitudinal  fibres  commence  by  four  branches  (the  tendons 
of  the  bladder,  or  of  the  detrusor  urinse),  two  superior  from  the  os 
pubis,  and  two  inferior  from  the  ramus  of  the  ischium  on  each  side, 
and  spread  out  as  they  ascend  upon  the  anterior  surface  of  the  blad- 
der to  its  fundus;  they  then  converge  upon  the  posterior  surface  of 
the  organ,  and  descend  to  its  neck  where  they  are  inserted  into  the 
isthmus  of  the  prostate  gland,  and  into  a  ring  of  elastic  tissue,  which 
surrounds  the  commencement  of  the  prostatic  portion  of  the  urethra. 
Some  of  the  anterior  fibres  are  also  attached  to  this  ring.  The 
lateral  fibres  commence  at  the  prostate  gland  and  the  elastic  ring 
of  the  urethra  on  one  side,  and  spread  out  as  they  ascend  upon  the 
side  of  the  bladder  to  descend  upon  the  opposite  side,  and  be  inserted 
into  the  prostate  and  opposite  segment  of  the  same  ring.  Two 
bands  of  oblique  fibres  arc  described  by  Sir  Charles  Bell,  as  ori- 


BLADDER. 


559 


ginating  at  the  terminations  of  the  ureters,  and  converging  to  thd 
neck  of  the  bladder;  the  existence  of  these  muscles  is  not  well  es- 
tablished. 

It  has  been  well  shown  by  Mr.  Guthrie,*  that  there  are  no  fibres 
at  the  neck  of  the  bladder  capable  of  forming  a  sphincter  vesicas. 
The  fibres  corresponding  with  the  trigonum  vesicas  are  transverse. 

Sir  Astley  Cooper  has  demonstrated  around  the  neck  of  the  bladder 
within  the  prostate  gland,  a  ring  of  elastic  tissue,  which  has  for  its 
object  the  mechanical  closure  of  the  urethra  against  the  involuntary 
passage  of  the  urine.  It  is  into  this  elastic  ring  that  the  longitudinal 
fibres  of  the  detrusor  urinas  are  inserted,  so  that  this  muscle  taking 
a  fixed  point  at  the  os  pubis  will  not  only  compress  the  bladder,  and 
thereby  tend  to  force  its  contents  along  the  urethra  ;  but  will  at  the 
same  time,  by  means  of  its  attachment  to  this  ring  dilate  the  en- 
trance of  the  urethra,  and  afford  a  free  egress  to  the  contents  of  the 
bladder.f 

*  "  On  the  Anatomy  and  Diseases  of  the  Neck  of  the  Bladder  and  of  the  Urethra." 

t  In  Horner's  Special  Anatomy,  vol.  ii.  p.  89,  we  find  a  different  account  of  the 
sphincter  apparatus  at  the  neck  of  the  bladder,  which  I  subjoin  because  I  have  found 
it  correct  in  every  case  which  I  have  examined.  On  one  point  I  beg  leave  to  differ 
from  Prof.  Horner's  description,  viz.:  in  place  of  considering-  the  transverse  band  con- 
necting  the  two  lobes  of  the  prostate,  and  the  triangular  lamina  underlying  the  vesical 
triangle  as  muscular,  I  believe  them  to  belong  to  the  proper  elastic  tissue  such  as  forms 
the  ligamentum  nuchse  in  the  mammiferse  and  the  middle  coat  of  the  arterial  system. 
I  annex  a  cut  to  the  description  of  Horner,  taken  by  his  permission  from  a  drawing  by 
Peale.— G. 

"The  internal  orifice  of  the  neck  of  Fig.  191. 

the  bladder  resembles  strongly  that  of  a 
Florence  flask,  modified,  however,  by 
the  projection  of  the  uvula  vesicee,  which 
makes  it  somewhat  crescentic  below. 
The  neck  of  the  bladder  penetrates  the 
prostate  gland,  but,  at  its  commence- 
ment, is  surrounded  by  loose  cellular 
tissue  containing  a  very  large  and  abun- 
dant plexus  of  veins.  The  internal  layer 
of  muscular  fibres  is  here  transverse ; 
and  they  cross  and  intermix  with  each 
other  in  different  directions,  forming  a 
close  compact  tissue,  which  has  the 
effect  of  a  particular  apparatus  for  re- 
taining the  urine,  and  is  called  muscu- 
lus  sphincter  vesicae  urinarise.  Gene- 
rally, anatomists  have  not  considered 
this  structure  as  distinct  from  the  mus- 
cular coat  at  large  ;  but  Sir  Charles  Bell, 
now  a  professor  in  the  University  of 
Edinburgh,  wiiose  reputation  as  an  ana- 
tomist is  well  established,  gives  the  fol- 
lowing account  of  it: 

"  '  Begin  the  dissection  by  taking  off 
the  inner  membrane  of  the  bladder  from 
around  the  orifice  of  the  urethra,  A  set 
of  fibres  will  be  discovered,  on  the  lower  half  of  the  orifice,  which,  bemg  carefully  dis- 

Fig.  191.  Represents  the  neck  of  the  bladder  with  the  sphincter  apparatus  as  de- 
scribed by  Horner.  1,  1.  Orifice  of  the  neck  of  the  bladder.  2,  2,  2,  2.  Orifices  of  the 
ureters.  .3,  3.  The  triangular  tissue,  supposed  to  be  muscular  under  the  mucous  mem- 
brane of  the  vesical  triangle.  4,  4.  Fart  of  the  detrusor  urina  muscle.  5.  The  elastic 
band  which  acts  as  a  constant  sphincter  to  the  neck  of  the  bladder. — G. 


560  PROSTATE  6LAKD. 

The  Mucous  coat  is  thin  and  smooth  and  exactly  moulded  upon 
the  muscular  coat,  to  which  it  is  connected  by  a  somewhat  thick 
layer  of  submucous  tissue,  called  by  some  anatomists,  the  nervoi.is 
coat;  its  papillae  are  very  minute,  and  there  is  scarcely  a  trace  of 
mucous  follicles.  This  mucous  membrane  is  continuous  through 
the  ureters  with  the  lining  membrane  of  the  uriniferous  ducts,  and 
through  the  urethra  with  that  of  the  prostatic  ducts,  tubuli  semi- 
niferi,  and  Cowper's  glands. 

Upon  the  internal  surface  of  the  base  of  the  bladder  is  a  triangu- 
lar smooth  plane  of  a  paler  colour  than  the  rest  of  the  mucous  mem- 
brane ;  the  trigonum  vesicas,  or  trigone  vesicale.  This  is  the  most 
sensitive  part  of  the  bladder,  and  the  pressure  of  calculi  upon  it 
gives  rise  to  great  suffering.  It  is  bounded  on  each  side  by  the 
raised  ridge,  corresponding  with  the  muscles  of  the  ureters,  at  each 
posterior  angle  by  the  openings  of  the  ureters,  and  in  front  by  a 
slight  elevation  of  the  mucous  membrane  at  the  entrance  of  the  ure- 
thra, called  the  uvula  vesiccB. 

The  external  surface  of  the  base  of  the  bladder  corresponding 
with  the  trigonum,  is  also  triangular,  and  is  separated  from  the 
rectum  merely  by  a  thin  layer  of  fibrous  membrane,  the  recto-vesical 
fascia.  It  is  bounded  behind  by  the  recto-vesical  fold  of  peritoneum  ; 
and  on  each  side  by  the  vas  deferens,  and  vesicula  seminalis,  which 
converge  almost  to  a  point  at  the  base  of  the  prostate  gland.  It  is 
through  this  space  that  the  opening  is  made  in  the  recto-vesical 
operation  for  puncture  of  the  bladder. 

PROSTATE    GLAND. 

The  prostate  gland  (w^ottfTTjfAt  pr^ponere)  is  situated  in  front  of  the 
neck  of  the  bladder  behind  the  deep  perineal  fascia  and  upon  the 

sected,  will  be  found  to  run  in  a  semicircular  form  round  the  urethra.  These  fibres 
make  a  band  of  about  half  an  inch  in  breadth,  particularly  strong  on  the  lower  part  of 
the  opening,  and,  having  mounted  a  little  above  the  orifice,  on  each  side,  they  dispose 
of  a  portion  of  their  fibres  in  the  substance  of  the  bladder.  A  smaller  and  somewhat 
weaker  set  of  fibres  will  be  seen  to  complete  their  course,  surrounding  the  orifice  on 
the  upper  part ;  to  these  sphincter  fibres  a  bridle  is  joined,  which  comes  from  the  union 
of  the  muscles  of  the  ureters.' 

"  After  repeated  observations  on  this  point,  I  have  come  to  the  conclusion  that  Mr. 
Bell  has  indicated  a  real  structure;  but  my  own  dissections  have  resulted  as  follows: 
The  inferior  semicircumference  of  the  neck  of  the  bladder  is  surrounded  by  a  thick 
fasciculus  of  muscular  fibre,  half  an  inch  wide,  running  in  a  transverse  direction,  and 
having  its  ends  attached  to  the  lateral  lobes  of  the  prostate  gland,  being  above  the  tiiird 
lobe  of  the  latter.  This  fasciculus  is  perfectly  distinct  from  the  ordinary  muscular 
fibre  of  the  bladder,  and  resembles  in  its  texture  the  musculo-fibrous  coat  of  the  arte- 
ries. The  superioi'  semicircumference  is  also  surrounded  by  a  thin  layer  of  muscular 
fibres  of  an  ordinary  kind,  forming  a  broad,  thin  band  of  a  crcscenlic  shape,  the  lower 
ends  of  which  arc  insensibly  lost  in  the  adjacent  muscular  coat  of  the  bladder  by  being 
spread  out.  And,  lastly,  beneath  the  mucous  membrane  of  the  vesical  triangle  there 
is  a  triangular  muscle  of  the  same  size  as  the  vesical  triangle.  Having  elongated 
angles,  the  anterior  angle  may  be  traced  to  the  posterior  part  of  the  caput  gallinaginis, 
and  the  posterior  angles  to  the  orifices  of  the  ureters  and  the  adjacent  part  of  the 
bladder.  The  texture  of  this  muscle  is  also  like  that  of  the  musculo-fibrous  coat  of  the 
arteries.  When  a  bladder  is  recent,  this  detail  of  structure  is  made  out  with  difficulty : 
it  requires  to  be  previously  hardened  in  spirits  of  wine.  That  a  power  exists  in  the 
neck  of  the  bladder  of  retaining  eorn|iietely  tiie  urine,  has  been  satisfactorily  demon, 
strated  to  me  in  a  case  of  fistula  in  perineo,  which  was  presented  to  the  notice  of  the 
late  Dr.  Physick  and  myself,  a  few  years  ago." 


VESICUL^  SEMINALES.  561 

rectum,  through  which  it  may  be  distinctly  felt.  It  surrounds  the 
commencement  of  the  urethra  for  a  little  more  than  an  inch  of  its 
extent,  and  resembles  a  Spanish  chestnut  both  in  size  and  form;  the 
base  being  directed  backwards  towards  the  neck  of  the  bladder,  the 
apex  forwards,  and  the  convex  side  towards  the  rectum.  It  is  re- 
tained firmly  in  its  position  by  the  two  superior  and  the  two  inferior 
tendons  of  the  bladder,  by  the  attachments  of  the  pelvic  fascia,  and 
by  a  process  of  the  internal  layer  of  the  deep  perineal  fascia,  which 
forms  a  sheath  around  the  membranous  urethra,  and  is  inserted  into 
the  apex  of  the  gland.  It  consists  of  three  lobes,  two  lateral  and  a 
middle  lobe  or  isthmus  ;  the  lateral  lobes  are  distinguished  by  an  in- 
dentation upon  the  base  of  the  gland,  and  by  a  slight  furrow  upon 
its  upper  and  lower  surface.  The  third  lobe  or  isthmus  is  a  small 
transverse  band  which  passes  between  the  two  lateral  lobes  at  the 
base  of  the  organ.  In  structure  the  prostate  gland  is  composed  of 
ramified  ducts,  terminating  in  lobules  of  follicular  pouches  which 
are  so  closely  compressed  as  to  give  to  a  thin  section  of  the  gland  a 
cellular  appearance  beneath  the  microscope.  It  is  pale  in  colour 
and  hard  in  texture,  splits  easily  in  the  course  of  its  ducts,  and  is 
surrounded  by  a  plexus  of  veins  which  are  enclosed  by  the  strong 
fibrous  membrane  with  which  it  is  invested.  Its  secretion  is  poured 
into  the  prostatic  portion  of  the  urethra  by  fifteen  or  twenty  excre- 
tory ducts.  The  urethra  in  passing  through  the  prostate  lies  one 
third  nearer  to  its  upper  than  to  its  lower  surface. 

VESICUL^    SEMINALES. 

Upon  the  under  surface  of  the  base  of  the  bladder,  and  converging 
towards  the  base  of  the  prostate   gland, 
are  two  lobulated  and  somewhat  pyriforni  ^ig- 192. 

bodies,  about  two  inches  in  length,  the  vesi- 
culee  seminales.  Their  upper  surface  is  in 
contact  with  the  base  of  the  bladder ;  the 
under  side  rests  upon  the  rectum,  separated 
only  by  the  recto- vesical  fascia;  the  larger 
extremities  are  directed  backwards  and 
outwards,  and  the  smaller  ends  almost  meet 
at  the  base  of  the  prostate.  They  enclose 
between  them  a  triangular  space,  which  is 
bounded  posteriorly  by  the  recto- vesical  fold 
of  peritoneum,  and  which  corresponds  with 
the  trigonum  vesicie  on  the  interior  of  the 
bladder.  Each  vesicula  is  formed  by  the 
convolutions  of  a  single  tube,  which  gives 
off  several  irregular  cascal  branches.     It  is 

Fig.  192.  The  posterior  aspect  of  the  male  bladder;  the  serous  coverinor  is  removed 
in  order  to  show  the  muscular  coat.  1.  The  body  of  the  bladder.  2.  Its  fundus.  3. 
Its  inferior  fundus  or  base.  4.  The  urachus.  5,  5.  The  ureters.  6,  6.  The  vus  defe- 
rentia.  7,  7.  The  vesiculfB  seminales.  The  triangular  area,  corresponding  with  the 
trigonum  vesicoe,  through  which  the  bladder  would  be  pierced  in  puncturing  the  blad- 
der  through  the  rectum.  The  dotted  line  forming  the  base  of  this  triangular  area, 
marks  the  extent  of  the  recto-vesical  fold  of  the  peritoneum. 


562  MALE  OKGANS  OF  GENERATION. 

enclosed  in  a  dense  fibrous  membrane,  derived  from  the  pelvic  fascia, 
and  is  constricted  beneath  the  isthmus  of*  the  prostate  gland  into  a 
small  excretory  duct.  The  vas  deferens,  somewhat  enlarged  and 
convoluted,  lies  along  the  inner  border  of  each  vesicula,  and  is  in- 
cluded in  its  fibrous  investment.  It  communicates  with  the  duct  of 
the  vesicula,  beneath  the  isthmus  of  the  prostate,  and  forms*  the 
ejaculatory  duct.  The  ejaculatory  duct  is  about  three  quarters  of 
an  inch  in  length,  and  running  forwards,  first  between  the  base  of 
the  prostate  and  the  isthmus  and  then  through  the  elastic  tissue  of 
the  veru  montanum,  opens  upon  the  mucous  membrane  of  the 
urethra,  near  to  its  fellow  of  the  opposite  side,  at  the  anterior  ex- 
tremity of  that  process. 

MALE    ORGANS   OF    GENERATION^. 

The  organs  of  generation  in  the  male  are,  the  penis  and  the  testes, 
with  their  appendages. 

The  Penis  is  divided  into  a  body,  root,  and  extremity.  The  body 
is  surrounded  by  a  thin  integument,  which  is  remarkable  for  the 
looseness  of  its  cellular  connexion  with  the  deeper  parts  of  the 
organ,  and  for  containing  no  adipose  tissue.  The  j'oot  is  broad  and 
firmly  adherent  to  the  rami  of  the  os  pubis  and  ischium  by  means 
of  two  strong  processes,  the  crura,  and  is  connected  to  the  sym- 
physis pubis  by  a  fibrous  membrane,  the  ligamentum  suspensorium. 
The  extremUy,  or  glans  penia  resembles  an  obtuse  cone,  somewhat 
compressed  from  above  downwards,  and  of  a  deeper  red  colour 
than  the  surrounding  skin.  At  its  apex  is  a  small  vertical  slit,  the 
meatus  urinarius,  which  is  bounded  by  two  more  or  less  protuberant 
labia ;  and,  extending  backwards  from  the  meatus,  is  a  depressed 
raphe,  to  which  is  attached  a  loose  fold  of  mucous  membrane,  the 
fra3num  prseputii.  The  base  of  the  glans  is  marked  by  a  projecting 
collar,  the  corona  glandis,  upon  which  are  seen  a  number  of  small 
papillary  elevations,  formed  by  the  aggregation  of  minute  sebaceous 
glands,  the  gland ula3  Tysoni  (odoriferce).  Behind  the  corona  is  a 
deep  fossa,  bounded  by  a  circular  fold  of  integument,  the  prcEpiitium, 
which,  in  the  quiescent  state  of  the  organ,  may  be  drawn  over  the 
glans,  but,  in  its  distended  state,  is  obliterated,  and  serves  to  facili- 
tate its  enlargement.  The  internal  surface  of  the  prepuce  is  lined 
by  mucous  membrane,  covered  by  a  thin  cuticle;  this  membrane, 
upon  reaching  the  base  of  the  glans,  is  reflected  over  the  glans  penis, 
and,  at  the  meatus  urinarius,  becomes  continuous  with  the  mucous 
lining  of  the  urethra. 

The  penis  is  composed  of  the  corpus  cavernosum  and  corpus 

*  It  has  been  customary  hitherto,  in  works  on  anatomy,  to  describe  tlie  course  of 
excretory  ducts  as  procodding-  from  the  gland,  and  passing  thence  to  tlic  point  at  which 
the  secretion  is  poured  out.  In  the  description  of  the  vas  deferens,  with  its  connexion 
with  the  duct  of  the  vesicula  scminalis,  I  have  adopted  this  plan,  that  I  might  not  too 
far  depart  from  established  habit.  Dut  as  it  is  more  correct  and  consistent  with  the 
present  stutc  of  science  to  consider  the  gland  as  a  developement  of  the  duct,  I  have 
pursued  the  latter  principle  in  the  description  of  most  of  the  other  glandular  organs  of 
the  body. 


CORPUS  SPONGIOSUM — ERECTILE  TISSUE.  563 

spongiosum,  and  contains  in  its  interior  the  longest  portion  of  the 
urethra. 

The  Corpus  cavernosum  is  distinguished  into  two  lateral  portions 
(corpora  cavernosa),  by  an  imperfect  septum  and  by  a  superior  and 
inferior  groove,  and  is  divided  posteriorly  into  two  crura.  It  is 
firmly  adherent,  by  means  of  its  crura,  with  the  ramus  of  the  os 
pubis  and  ischium.  It  forms,  anteriorly,  a  single  rounded  extremity, 
which  is  received  into  a  fossa  in  the  base  of  the  glans  penis;  the 
superior  groove  lodges  the  dorsal  vessels  of  the  organ,  and  the  infe- 
rior receives  the  corpus  spongiosum.  Its  fibrous  tunic  is  thick, 
elastic,  and  extremely  firm,  and  sends  a  number  of  fibrous  bands 
and  cords  (trabeculaj)  inwards  from  its  inferior  groove,  which  cross 
its  interior  iri  a  radiating  direction,  and  are  inserted  into  the  inner 
walls  of  the  tunic.  These  trabeculte  are  most  abundant  on  the 
middle  line,  where  they  are  ranged  vertically,  side  by  side,  some- 
what like  the  teeth  of  a  comb,  and  constitute  the  imperfect  partition 
of  the  corpus  cavernosum,  called  the  septum  pectiniforme.  This 
septum  is  more  complete  at  its  posterior  than  towards  its  anterior 
part. 

The  tunic  of  the  corpus  cavernosum  consists  of  strong  longitu- 
dinal fibrous  fasciculi,  closely  interwoven  with  each  other.  Its  in- 
ternal structure  is  composed  of  erectile  tissue. 

The  Corpus  spongiosum  is  situated  along  the  under  surface  of  the 
corpus  cavernosum,  in  its  inferior  groove.  It  commences  by  its 
posterior  extremity  between  and  beneath  the  crura  penis,  where 
it  forms  a  considerable  enlargement,  the  bulb,  and  terminates  an- 
teriorly by  another  expansion,  the  glans  penis.  Its  middle  portion, 
or  body,  is  nearly  cylindrical,  and  tapers  gradually  from  its  pos- 
terior towards  its  anterior  extremity.  The  bulb  is  adherent  to  the 
deep  perineal  fascia  by  means  of  the  tubular  prolongation  of  the  an- 
terior layer,  which  surrounds  the  membranous  portion  of  the  urethra; 
in  the  rest  of  its  extent  the  corpus  spongiosum  is  attached  to  the 
corpus  cavernosum  by  cellular  tissue,  and  by  veins  which  wind 
around  that  body  to  reach  the  dorsal  vein.  It  is  composed  of  erec- 
tile tissue,  enclosed  by  a  dense  fibrous  tissue,  much  thinner  than  that 
of  the  corpus  cavernosum,  and  contains  in  its  interior  the  spongy 
portion  of  the  urethra,  which  lies  nearer  to  its  upper  than  to  its 
lower  wall. 

Erectile  tissue  is  a  peculiar  cellulo-vascular  structure,  entering  in 
considerable  proportion  into  the  composition  of  the  organs  of  gene- 
ration. It  consists  essentially  of  a  plexus  of  veins  so  closely  con- 
voluted and  interwoven  with  each  other,  as  to  give  rise  to  a  cellular 
appearance  when  examined  upon  the  surface  of  a  section.  The 
veins  forming  this  plexus  are  smaller  in  the  glans  penis,  corpus  spon- 
giosum, and  circumference  of  the  corpus  cavernosum,  than  in  the 
central  part  of  the  latter,  where  they  are  large  and  dilated.  They 
have  no  Qther  coat  than  the  internal  lining  prolonged  from  the 
neighbouring  veins;  and  the  interstices  of  the  plexus  are  occupied 
by  a  peculiar  reddish  fibrous  substance.     They  receive  their  blood 


564  URETHRA. 

from  the  capillaries  of  the  arteries  in  the  same  manner  with  veins 
generally,  and  not  by  means  of  vessels  having  a  peculiar  form  and 
distribution,  as  described  by  Miiller.  The  helicine  arteries  of  that 
physiologist  have  no  existence.* 

Vessels  and  Nerves. — The  arteries  of  the  penis  are  derived  from 
the  internal  pudic;  they  are,  the  arteries  of  the  bulb,  arteries  of  the 
corpus  cavernosum,  and  dorsalis  penis.  .Its  veins  are  superficial  and 
deep.  The  deep  veins  run  by  the  side  of  the  deep  arteries,  and  ter- 
minate in  the  internal  pudic  veins.  The  superficial  veins  emerge  in 
considerable  number  from  the  base  of  the  glans,  and  converge  on 
the  dorsum  penis,  to  form  a  large  dorsal  vein,  which  receives  other 
veins  from  the  corpus  cavernosum  and  spongiosum  in  its  course,  and 
passes  backwards  between  two  layers  of  the  ligamentum  suspen- 
sorium,  and  through  the  deep  fascia  beneath  the  arch  of  the  os  pubis, 
to  terminate  in  the  prostatic  and  vesical  plexuses. 

The  Lymphatics  terminate  in  the  inguinal  glands.  The  nerves  are 
derived  from  the  internal  pudic  nerve,  from  the  sacral  plexus,  and, 
as  shown  by  Professor  Miiller  in  his  beautiful  monograph,  from  the 
hypogastric  plexus. 

URETHRA. 

The  urethra  is  the  membranous  canal  extending  from  the  neck 
of  the  bladder  to  the  meatus  urinarius.  It  is  sigmoid  in  its  course, 
and  is  composed  of  two  layers,  a  mucous  coat  and  an  elastic  fibrous 
coat.  The  mucous  coat  is  thin  and  smooth ;  it  is  continuous,  inter- 
nally, with  the  mucous  membrane  of  the  bladder ;  externally,  with 
the  investing  membrane  of  the  glans;  and,  in  certain  points  of  its 
extent,  with  the  lining  membrane  of  the  numerous  ducts  of  mucous 
glands, — of  those  of  Cowper's  glands,  the  prostate  gland,  vasa 
dcferentia,  and  vesiculse  seminales.  The  elastic  fibrous  coat  varies 
in  thickness  in  the  different  parts  of  the  course  of  the  urethra:  it  is 
thick  in  the  prostate  gland,  forms  a  firm  investment  for  the  mem- 
branous portion  of  the  canal,  and  is  thin  in  the  spongy  portion, 
where  it  serves  as  a  bond  of  connexion  between  the  mucous  mem- 
brane and  the  corpus  spongiosum.  The  urethra  is  about  nine  inches 
in  length,  and  is  divided  into  a  prostatic,  membranous,  and  spongy 
portion. 

The  Prostatic  portion,  a  little  more  than  an  inch  in  length,  is 
situated  in  the  prostate  gland,  about  one-third  nearer  to  its  upper 
than  to  its  lower  surface,  and  extending  from  its  base  to  its  fipex. 
Upon  its  lower  circumference  or  floor  is  a  longitudinal  fold  of  mucous 
membrane — the  verurnontamim,  or  caput  gallinaginis, — and  on  each 
side  of  the  veru,  a  depressed  fossa — the  prostatic  sinus — in  which 
are  seen  the  numerous  openings  of  the  prostatic  ducts.  At  the  an- 
terior extremity  of  the  verumontanum  are  the  openings  of  the  two 
ejaculatory  ducts,  and  between  them  a  third  opening,  which  leads 

*  See  my  investigation  upon  this  structure  in  the  "  Cyclopoedia  of  Anatomy  and 
Physiology."    Ariicie,  "  Penis." 


URETHRA  AND  BLADDER. 


565 


backwards  into  a  small  dilated  sac — the  sinus  pocularis.  The  pro- 
static portion  of  the  urethra,  when  distended,  is  the  most  dilated  part 
of  the  canal ;  but,  excepting  during  the  passage  of  urine,  is  com- 
pletely closed  by  means  of  a  ring  of  elastic  tissue  which  encircles 
the  urethra  as  far  as  the  anterior  extremity  of  the  verumontanuni. 
In  the  contracted  state  of  the  urethra,  the  verumontanurn  acts  as 
a  valve,  being  pressed  upwards  against  the  upper  wall  of  the  canal ; 

Fig.  193. 


but,  during  the  action  of  the  detrusor  muscle  of  the  bladder,  the 
whole  elastic  ring  is  expanded  by  the  muscular  fibres  which  are 
inserted  into  it ;  and  the  veru  is  especially  drawn  downwards  by 
two  delicate  tendons,  which  have  been  traced  by  Mr.  Tyrrell, 
from  the  posterior  fibres  of  the  detrusor  into  the  tissue  of  this 
process. 

Fig.  193.  A  longitudinal  section  of  the  bladder,  prostate  gland,  and  penis,  showing 
the  urethra.  1.  The  urachus  attached  to  the  upper  part  of  the  fundus  of  the  bladder. 
2.  The  recto-vesical  fold  of  peritoneum,  at  its  point  of  reflection  from  the  base  of  the 
bladder,  upon  the  anterior  surface  of  the  rectum.  3.  The  opening  of  the  right  ureter. 
4.  A  slight  ridge,  formed  by  the  muscle  of  the  ureter,  and  extending  from  the  termi- 
nation  of  the  ureter  to  the  commencement  of  the  urethra.  This  ridge  forms  the  lateral 
boundary  of  the  trigonum  vesica?.  5.  The  commencement  of  the  urethra  ;  the  eleva- 
tion of  mucous  membrane  immediately  behind  the  figure  is  the  uvula  vesicte.  The 
constriction  of  the  bladder  at  this  point  is  the  neck  of  the  bladder.  6.  The  prostatic 
portion  of  the  urethra.  7.  The  prostate  gland;  the  difference  of  thickness  of  the 
gland,  above  and  below  the  urethra,  is  shown.  8.  The  isthmus,  or  third  lobe  of  the 
prostate;  immediately  beneath  which  the  ejaculatory  duct  is  seen  passing.  9.  The 
right  vesicula  seminalis;  the  vas  deferens  is  seen  to  be  cut  short  off,  close  to  its  junc. 
tion  with  the  ejaculatory  duct.  10.  The  membranous  portion  of  the  urethra.  11. 
Cowper's  gland  of  the  right  side,  with  its  duct.  12.  The  bulbous  portion  of  the 
urethra ;  tliroughout  the  whole  length  of  the  urethra  of  the  corpus  spongiosum,  nu- 
merous lacunEe  are  seen.  13.  The  fossa  navicularis.  14.  The  corpus  cavernosum,  cut 
somewhat  obliquely  to  the  right  side,  near  its  lower  part.  The  character  of  the  venous 
cellular  texture  is  well  shown.  15.  The  right  crus  penis.  16.  Near  the  upper  part  of 
the  corpus  cavernosum,  the  section  has  fallen  a  little  to  the  left  of  the  middle  line  ;  a 
portion  of  the  septum  pectiniforme  is  consequently  seen.  This  figure  also  indicates 
the  thickness  of  the  fibrous  investment  of  the  corpus  cavernosum,  and  its  abrupt  ter- 
mination at  the  base  of  (17)  the  glans  penis.  18.  Tlie  lower  segment  of  the  ghiiis. 
19.  The  meatus  urinarius.  20.  The  corpus  spongiosum.  21.  The  bulb  of  the  corpus 
spongiosum. 

48 


566  MEMBKANOtTS  URETHRA. 

The  discovery  of  this  beautiful  structure  is  due  to  our  distin- 
guished countryman,  Sir  Astley  Cooper,  and  is  one  other  instance 
of  the  marvellous  indications  of  design  evinced  in  the  structure  of 
the  animal  frame.  Instead  of  a  muscular  apparatus,  liable  to  fatigue, 
Nature  has  employed,  for  the  purpose  of  retaining  the  urine,  an 
elastic  substance,  which  closes  the  urethra  constantly  by  an  unweary- 
ing physical  property.  Expulsion,  on  the  contrary,  occurring  only 
at  intervals,  demands  the  exercise  of  muscular  action,  that  action 
being  immediately  applied  to  the  elastic  agent  and  drawing  it  aside. 
It  is  by  means  of  this  interesting  provision  that  the  semen  and  the 
last  drops  of  urine  are  expelled  from  the  urethra  without  a  chance 
of  reflux  into  the  bladder,  and  that  the  urine  is  enabled  to  pass  freely 
along  its  canal  without  danger  of  entering  the  prostatic  or  ejacula- 
tory  ducts. 

The  Membranous  •portion,  the  narrowest  part  of  the  canal,  is 
somewhat  less  than  an  inch  in  length.  It  is  situated  between  the 
two  layers  of  the  deep  perineal  fascia,  and  is  surrounded  by  the 
fan-like  expansions  of  the  upper  and  lower  segments  of  the  com- 
pressor urethrse  muscle  which  meet  at  the  raphe  along  its  upper  and 
lower  surface.  It  is  continuous  posteriorly  with  the  prostatic 
urethra,  and  anteriorly  with  the  spongy  portion  of  the  canal.  Its 
coverings  are  the  mucous  membrane,  elastic  fibrous  layer,  com- 
pressor urethrse  muscle,  and  a  partial  sheath  from  the  deep  perineal 
fascia. 

The  Spongy  portion  forms  the  rest  of  the  extent  of  the  canal,  and 
is  lodged  in  the  corpus  spongiosum  from  its  commencement  at  the 
deep  perineal  fascia  to  the  meatus  urinarius.  It  is  narrowest  in  the 
body,  and  becomes  dilated  at  either  extremity,  posteriorly  in  the 
bulb,  where  it  is  named  the  bulbous  portion,  and  anteriorly  in  the 
glans  penis,  where  it  forms  the  fossa  navicularis.  The  meatus 
urinarius  is  the  most  constricted  part  of  the  canal;  so  that  a  cathe- 
ter, which  will  enter  that  opening,  may  be  passed  freely  through  the 
whole  extent  of  a  healthy  urethra.  Opening  into  the  bulbous  portion 
are  two  small  excretory  ducts  about  three  quarters  of  an  inch  in 
length,  which  may  be  traced  backwards,  between  the  coats  of  the 
urethra  and  the  bulb,  to  the  interval  between  the  two  layers  of  the 
deep  perineal  fascia,  where  they  ramify  in  two  small  lobulated  and 
somewhat  compressed  glands  of  about  the  size  of  peas.  These  are 
Cowper's  glands  ;  they  are  situated  immediately  beneath  the  mem- 
branous portion  of  the  urethra,  and  are  enclosed  by  the  lower  seg- 
ment of  the  compressor  urethrse  muscle  so  as  to  be  subject  to  mus- 
cular compression.  Upon  the  whole  of  the  internal  surface  of  the 
spongy  portion  of  the  urethra,  particularly  along  its  upper  wall,  are 
numerous  small  openings  or  lacunae  which  are  the  entrances  of 
mucous  glands  situated  in  the  submucous  cellular  tissue.  The 
openings  of  these  lacuna?  are  directed  forwards,  and  are  liable  occa- 
sionally to  intercept  the  point  of  a  small  catheter  in  its  passage  into 
the  bladder.  At  about  an  inch  and  a  half  from  the  opening  of  the 
meatus  one  of  these  lacuna)  is  generally  found  much  larger  than  the 


TESTES.  567 


rest,  and  is  named  the  lacuna  magna.  In  a  beautiful  preparation 
of  this  lacuna,  made  by  Sir  Astley  Cooper,  the  extremity  of  the 
canal  presents  several  large  primary  ramifications. 


TESTES. 


The  testes  are  two  small  glandular  organs  suspended  from  the 
abdomen  by  the  spermatic  cords,  and  enclosed  in  an  external  tegu- 
mentary  covering,  the  scrotum. 

The  Scrotum  is  distinguished  into  two  lateral  halves  or  hemi- 
spheres by  a  raphe,  which  is  continued  anteriorly  along  the  under 
surface  of  the  penis,  and  posteriorly  along  the  middle  line  of  the 
perineum  to  the  anus.  Of  these  two  lateral  portions  the  left  is  some- 
what longer  than  the  right,  and  corresponds  with  the  greater  length 
of  the  spermatic  cord  on  the  left  side. 

The  scrotum  is  composed  of  two  layers,  the  integument  and  a 
proper  covering,  the  dartos;  the  integument  is  extremely  thin, 
transparent,  and  abundant,  and  beset  by  a  number  of  hairs  which 
issue  obliquely  from  the  skin,  and  have  prominent  roots.  The  dartos 
is  a  thin  layer  of  a  peculiar  contractile  fibrous  tissue,  intermediate 
in  properties  between  muscular  fibre  and  elastic  tissue ;  it  forms  the 
proper  tunic  of  the  scrotum,  and  sends  inwards  a  distinct  septum 
(septum  scroti)  which  divides  it  into  two  cavities  for  the  two  testes. 
The  dartos  is  continuous  around  the  base  of  the  scrotum  with  the 
common  superficial  fascia  of  the  abdomen  and  perineum. 

The  Spermatic  cord  is  the  medium  of  communication  between  the 
testes  and  the  interior  of  the  abdomen ;  it  is  composed  of  arteries, 
veins,  lymphatics,  nerves,  the  excretory  duct  of  the  testicle  and  its 
proper  coverings.  It  commences  at  the  internal  abdominal  ring, 
where  the  vessels  of  which  it  is  composed  converge,  and  passes 
obliquely  along  the  spermatic  canal ;  the  cord  then  escapes  at  the 
external  abdominal  ring  and  descends  through  the  scrotum  to  the 
posterior  border  of  the  testicle.  The  left  cord  is  somewhat  longer 
than  the  right,  and  permits  the  left  testicle  to  reach  a  lower  level 
than  the  right. 

The  Arteries  of  the  spermatic  cord  are  the  spermatic  artery  from 
the  aorta  ;  the  deferential  artery,  accompanying  the  vas  deferens, 
from  the  superior  vesical ;  and  the  cremasteric  branch  from  the 
epigastric  artery.  The  spermatic  veins  form  a  plexus  which  con- 
stitutes the  chief  bulk  of  the  cord  ;  they  are  provided  with  valves  at 
short  intervals,  and  the  smaller  veins  have  a  peculiar  tendril-like 
arrangement  which  has  obtained  for  them  the  name  of  vasa  pampi- 
niformia.  The  lymphatics  are  of  large  size,  and  terminate  in  the 
lumbar  glands.  The  nerves  are  the  spermatic  plexus,  which  is 
derived  from  the  aortic  and  renal  plexus,  the  genital  branch  of  the 
genito-crural  nerve,  and  the  scrotal  branch  of  the  ilio-scrotal. 

The  Vas  deferens,  the  excretory  duct  of  the  testicle,  is  situated 
along  the  posterior  border  of  the  cord,  where  it  may  be  easily  dis- 
tinguished by  the  hard  and  cordy  sensation  which  it  communicates 
to  the  fingers.     Its  parietes  are  very  thick  and  tough,  and  its  canal 


568 


COVERINGS  OF  COED TESTIS. 


Fig.  194. 


extremely  small  and  lined  by  the  mucous  membrane  continued  from 
the  urethra. 

The  Coverings  of  the  spermatic  cord  are  the  spermatic  fascia, 
cremaster  muscle,  and  fascia  propria.  The  spermatic  fascia  is  a 
prolongation  of  the  intercolumnar  fascia,  derived  from  the  borders 
of  the  external  abdominal  ring  during  the  descent  of  the  testicle  in 
the  foetus.  The  cremasteric  covering  (erythroid)  is  the  thin  mus- 
cular expansion  formed  by  the  spreading  out  of  the  fibres  of  the 
cremaster,  which  is  likewise  carried  down  by  the  testis  during  its 
descent.  The  fascia  propria  is  a  continuation  of  the  infundibuliform 
process  from  the  transversalis  fascia  which  immediately  invests  the 
vessels  of  the  cord,  and  is  also  obtained  during  the  descent  of  the 
testis. 

The  Testis  (testicle)  is  a  small  oblong  and  rounded  gland,  some- 
what compressed  upon  the  sides  and  behind,  and  suspended  in  the 
cavity  of  the  scrotum  by  the  spermatic  cord. 

Its  position  in  the  scrotum  is  oblique;  so  that  the  upper  extremity 
is  directed  upwards  and  forwards,  and  a  little 
outwards ;  the  lower,  downwards  and  back- 
wards, and  a  little  inwards;  the  convex  sur- 
face looks  forwards  and  downwards,  and  the 
flattened  surface  to  which  the  cord  is  attached, 
backwards  and  upwards.  Lying  against  its 
outer  and  posterior  border  is  a  flattened  body 
which  follows  the  course  of  the  testicle,  and 
extends  from  its  upper  to  its  lower  extremity ; 
this  body  is  named,  from  its  relation  to  the 
testis,  epididymis  (s*/  upon,  SiSv^og  the  testicle) ; 
it  is  divided  into  a  central  part  or  body,  an 
upper  extremity  or  globus  major,  and  a  lower 
extremity,  globus  minor  (cauda)  epididymis. 
The  globus  major  is  situated  upon  the  upper 
end  of  the  testicle,  to  which  it  is  closely  adherent ;  the  globus  minor 
is  placed  at  its  lower  end,  is  attached  to  the  testis  by  cellular  tissue, 
and  curves  upwards,  to  become  continuous  with  the  vas  deferens. 
The  testis  is  invested  by  three  tunics — tunica  vaginalis,  tunica 
albuginea,  and  tunica  vasculosa ;  and  is  connected  to  the  inner  sur- 
face of  the  dartos  by  a  large  quantity  of  extremely  loose  cellular 
tissue,  in  which  fat  i^  never  deposited,  but  which  is  very  susceptible 
of  serous  infiltration. 

The   Tunica  vaginalis  is  a  pouch  of  serous  membrane  derived 

Figf.  li)4.  A  transverse  section  of  the  testicle.  1.  The  cavity  of  the  tunica  vaginalis  ; 
the  most  external  layer  is  the  tunica  vaginalis  rcflcxa ;  and  that  in  contact  with  the 
organ,  the  tunica  vaginalis  pro]jria,  2.  The  tunica  albuginea.  3.  The  mediastinum 
testis,  giving  off  numerous  fibrous  cords  in  a  radiated  direction  to  the  internal  surface 
of  the  tunica  albuginea.  Tlic  cut  extremities  of  tlie  vessels  below  the  number  belong 
to  the  rcte  testis;  and  those  above  to  tbe  arteries  and  veins  of  the  organ.  4.  The 
tunica,  vasculosa,  or  pia  mater  testis.  .5.  One  of  the  lobules,  consisting  of  the  convolu- 
tions of  tbe  tubuli  seninifori,  and  terminating  by  a  single  duct — the  vas  rectum.  Cor- 
responding lobules  are  seen  between  the  other  fibrous  cords  of  the  mediastinum.  6. 
Section  of  the  epididymis. 


STRUCTURE  OF  THE  TESTIS. 


569 


from  the  peritoneum  in  the  descent  of  the  testis,  and  afterwards 
obliterated  from  the  abdomen  to  within  a  short  distance  of  the  gland. 
Like  other  serous  coverings  it  is  a  shut  sac,  investing  the  organ  and 
thence  reflected  so  as  to  form  a  bag  around  its  circumference ;  hence 
it  is  divided  into  the  tunica  vaginalis  propria,  and  tunica  vaginalis 
refiexa.  The  tunica  vaginalis  propria  covers  the  surface  of  the 
tunica  albuginea,  and  surrounds  the  epididymis,  connecting  it  to  the 
testis  by  means  of  a  distinct  duplicature.  The  tunica  vaginaUs  re- 
flexa  is  attached  by  its  external  surface,  through  the  medium  of  a 
quantity  of  loose  cellular  tissue,  to  the  inner  surface  of  the  dartos. 
Betv^^een  the  two  layers  is  the  smooth  surface  of  the  shut  sac,  moist- 
ened by  its  proper  secretion. 

Fig.  195. 


The  Tunica  albuginea  (dura  mater  testis)  is  a  thick  fibrous  mem- 
brane of  a  bluish  white  colour,  and  the  proper  tunic  of  the  testicle. 
It  is  adherent  externally  to  the  tunica  vaginalis  propria,  and  from 
the  union  of  a  serous  with  a  fibrous  membrane  is  considered  a  fibro- 
serous  membrane,  like  the  dura  mater  and  pericardium.  After  sur- 
rounding the  testicle,  the  tunica  albuginea  is  reflected  from  its  pos- 
terior border  into  the  interior  of  the  gland,  and  forms  a  projecting 
longitudinal  ridge,  which  is  called  the  mediastinum  testis  (corpus 
Highmorianum*)  from  which  numerous  fibrous  cords  (trabeculee, 

Fig.  195.  Human  testis  injected  with  mercury.  1,  I.  Lobules  formed  of  seminife- 
rous tubes.  2.  Rete  testis.  3.  Vasa  eifcrentia.  4.  Plexuses  of  the  efferent  vessels 
passing-  into  the  head  of  the  epididymis  5,  5.  6.  Body  of  the  epididymis.  7.  Its  ap- 
pendix; its  tail  or  cauda.     8.  Vas  deferens. — (Lauth.) 

*  Nathaniel  Highmore,  a  physician  of  Oxford,  in  his  "Corporis  Humani  Disquisitio 
Anatomica,"  published  in  IG.iJ  :  he  considers  the  corpus  Highmorianum  as  a  duct 
formed  by  the  convergence  of  the  fibrous  cords,  which  he  mistakes  for  smaller  ducts. 

48* 


5:o 


EPIDIDYMIS. 


septula)  are  given  off,  to  be  inserted  into  the  inner  surface  of  the 
tunic.  The  mediastinum  serves  to  contain  the  vessels  and  ducts  of 
the  testicle  in  their  passage  into  the  substance  of  the  organ,  and  the 
fibrous  cords  are  admirably  fitted,  as  has  been  shown  by  Sir  Astley 
Cooper,  to  prevent  compression  of  the  gland.  If  a  transverse  section 
be  made  of  the  testis,  and  the  surface  of  the  mediastinum  examined, 
it  will  be  observed  that  the  blood-vessels  of  the  substance  of  the 
organ  are  situated  near  the  posterior  border  of  the  mediastinum, 
while  the  divided  ducts  of  the  rete  testis,  occupy  a  place  nearer  to 
the  free  margin. 

The  Tunica  vascuhsa  (pia  mater  testis)  is  the  nutrient  membrane 
of  the  testis  ;  it  is  situated  immediately  within  the  tunica  albuginea 
and  encloses  the  substance  of  the  gland,  sending  processes  inwards 
between  the  lobules,  in  the  same  manner  that  the  pia  mater  is  re- 
flected between  the  convolutions  of  the  brain. 

The  substance  of  the  testis  consists  of  numerous  conical  flattened 
lobules  (lobuli  testis),  the  bases  being  directed  towards  the  surface 
of  the  organ,  and  the  apices  towards  the  mediastinum.  Krause 
found  between  four  and  five  hundred  of  these  lobules  in  a  single 
testis.  Each  lobule  is  invested  by  a  distinct  sheath  formed  by  two 
layers,  one  being  derived  from  the  tunica  vas- 
culosa,  the  other  from  the  tunica  albuginea. 
The  lobule  is  composed  of  one  or  several 
minute  tubuli,  tubuli  semmiferi,*  exceedingly 
convoluted,  anastomosing  frequently  with  each 
other  near  to  their  extremities,  terminating  in 
loops  or  in  free  csecal  ends,  and  of  the  same 
diameter  (y|^  Lauth)  throughout.  The  tubuli 
seminiferi  are  of  a  bright  yellow  colour ;  they 
become  less  convoluted  in  the  apices  of  the 
lobules,  and  terminate  by  forming  between 
twenty  and  thirty  small  straight  ducts  of  about 
twice  the  diameter  of  the  tubuli  seminiferi, — 
the  vasa  recta.  The  vasa  recta  enter  the  sub- 
stance of  the  mediastinum,  and  terminate  in 
from  seven  to  thirteen  ducts, smaller  indiameter 
than  the  vasa  recta.  These  ducts  pursue  a  wav- 
ing course  from  below  upwards  through  the 
fibrous  tissue  of  the  mediastinum  ;  they  com- 
municate freely  with  each  other,  and  constitute 
the  rete  testis.     At  the  upper  extremity  of  the 


Fig.  196. 


Fig.  ]96.  Anatomy  of  the  testis.  1,  1.  The  tunica  albuginea.  2,  2.  The  mediasti- 
num testis.  .^,  .3.  The  lobuli  testis.  4,  4.  The  vasa  recta.  5,  5.  The  rete  testis,  6. 
The  vasa  cffercntia,  of  which  five  only  are  represented  in  this  diagram.  7.  The  coni 
vasculosi,  constituting  the  globus  major  of  the  epididymis.  8.  TJie  body  of  the  epi- 
didymis. 9.  The  globus  minor  of  the  epididymis.  10.  The  vas  deferens.  11.  The 
vasculum  aberrans. 

*  Lauth  estimates  the  whole  number  of  tubuli  scminifoi  in  each  testis,  at  840,  and 
their  average  length  at  2  feet  3  inches.  According  to  this  calculation,  the  whole  length 
of  the  tubuli  seminiferi  would  be  1890  feet. 


FEJIALE  PELVIS.  571 

mediastinum,  the  ducts  of  the  rete  testis  terminate  in  from  nine  to 
thirty  small  ducts,  the  vasa  efferentia,*  which  form  by  their  convolu- 
tions a  series  of  conical  masses,  the  coni  vasculosi ;  from  the  bases  of 
these  cones  tubes  of  larger  size  proceed,  which  constitute  by  their 
complex  convolutions  the  body  of  the  epididymis.  The  tubes  become 
gradually  larger  towards  the  lower  end  of  the  epididymis,  and  ter- 
minate in  a  single  large  and  convoluted  duct,  the  vas  deferens. 

The  Epididymis  is  formed  by  the  convolutions  of  the  excretory 
seminal  ducts,  externally  to  the  testis,  previously  to  their  termina- 
tion in  the  vas  deferens.  The  more  numerous  convolutions  and  the 
aggregation  of  the  coni  vasculosi  at  the  upper  end  of  the  organ 
constitute  the  globus  major ;  the  continuation  of  the  convolutions 
downwards  is  the  body ;  and  the  smaller  number  of  convolutions  of 
the  single  tube  at  the  lower  extremity,  the  globus  minor.  The  tubuli 
are  connected  together  by  a  very  delicate  cellular  tissue,  and  are 
enclosed  by  the  tunica  vaginalis. 

A  small  convoluted  duct,  of  variable  length,  is  generally  connected 
with  the  duct  of  the  epididymis  immediately  before  the  commence- 
ment of  the  vas  deferens.  This  is  the  vasculum  aberrans  of  Haller ; 
it  is  attached  to  the  epididymis  by  the  cellular  tissue  in  which  that 
body  is  enveloped.  Sometimes  it  becomes  dilated  towards  its  ex- 
tremity, but  more  frequently  retains  the  same  diameter  throughout. 

The  Vas  deferens  may  be  traced  upwards  in  the  course  of  the 
seminal  fluid,  from  the  globus  minor  of  the  epididymis  along  the 
posterior  part  of  the  spermatic  cord,  and  along  the  spermatic  canal 
to  the  internal  abdom.inal  ring.  From  the  ring  it  is  reflected 
inwards  to  the  side  of  the  fundus  of  the  bladder,  and  descends 
along  its  posterior  surface,  crossing  the  direction  of  the  ureter,  to 
the  inner  border  of  the  vesicula  seminalis.  In  this  situation  it 
becomes  somewhat  larger  in  size  and  convoluted,  and  terminates 
at  the  base  of  the  prostate  gland,  by  uniting  with  the  duct  of  the 
vesicula  seminalis  and  constituting  the  ejaculatory  duct.  The  eja- 
culatory  duct,  which  is  thus  formed  by  the  junction  of  the  duct  of 
the  vesicula  seminalis  with  the  vas  deferens,  passes  forwards  to  the 
anterior  extremity  of  the  verumontanum,  where  it  terminates  by 
opening  into  the  prostatic  urethra. 

FEMALE  PELVIS. 

The  peculiarities  of  the  form  of  the  female  pelvis  have  already 
been  examined  with  the  anatomy  of  the  bones.  Its  lining  bounda- 
ries are  the  same  with  those  of  the  male.  The  contents  are,  the 
bladder,  vagina,  uterus  with  its  appendages,  and  the  rectum.  Some 
portion  of  the  small  intestines  also  occupy  the  upper  part  of  its 
cavity. 

*  Each  vas  deferens  with  its  cone  measures,  according-  to  Lautli,  about  8  inches. 
The  entire  length  of  the  tubes  composing  the  epididymis,  according  to  the  same 
authority,  is  about  21  feet. 


572  VAGINA. 

The  Bladder  is  in  relation  with  the  os  pubis  in  front,  with  the 
uterus  behind,  from  which  it  is  usually  separated  by  a  convolution 
of  small  intestine,  and  with  the  neck  of  the  uterus,  and  with  the 
vagina  beneath.  The  form  of  the  female  bladder  corresponds  with 
that  of  the  pelvis,  being  broad  from  side  to  side,  and  often  bulging 
more  on  one  side  than  on  the  other.  This  is  particularly  evident 
after  frequent  parturition.  The  coats  of  the  bladder  are  the  same 
as  those  of  the  male. 

The  Urethra  is  about  an  inch  and  a  half  in  length,  and  is  lodged 
in  the  upper  wall  of  the  vagina,  in  its  course  downwards  and 
forwards,  beneath  the  arch  of  the  os  pubis,  to  the  meatus  urinarius. 
It  is  lined  by  mucous  membrane,  which  is  disposed  in  longitudinal 
folds,  and  is  continuous  internally  with  that  of  the  bladder,  and 
externally  with  the  vulva;  the  mucous  membrane  is  surrounded  by 
a  proper  coat  of  elastic  tissue,  to  which  the  muscular  fibres  of  the 
detrusor  urinas  are  attached.  It  is  to  this  tissue  that  is  due  the 
remarkable  dilatability  of  the  female  urethra,  and  its  speedy  return 
to  its  original  diameter.  The  meatus  is  encircled  by  a  ring  of 
fibrous  tissue,  which  prevents  it  from  distending  with  the  same 
facility  as  the  rest  of  the  canal ;  hence  it  is  sometimes  advan- 
tageous in  performing  this  operation  to  divide  its  margin  slightly 
with  the  knife. 

Vagina. — The  Vagina  is  a  membranous  canal,  leading  from  the 
vulva  to  the  uterus,  and  corresponding  in  direction  with  the  axis  of 
the  outlet  of  the  pelvis.  It  is  constricted  at  its  commencement,  but 
near  the  uterus  becomes  considerably  dilated ;  and  is  closed  by  the 
contact  of  the  anterior  with  the  posterior  wall.  Its  length  is  very 
variable ;  but  it  is  always  longer  upon  the  posterior  than  upon  the 
anterior  wall,  the  former  being  usually  about  five  or  six  inches  in 
length,  and  the  latter  four  or  five.  It  is  inserted  into  the  cervix  of 
the  uterus,  which  projects  into  the  upper  extremity  of  the  canal. 

In  Structure  the  vagina  is  composed  of  a  mucous  lining,  a  layer 
of  erectile  tissue,  and  an  external  tunic  of  a  cellulo-fibrous  structure, 
resembling  the  dartos  of  the  scrotum.  The  upper  fourth  of  the 
posterior  wall  of  the  vagina  is  covered,  on  its  pelvic  surface,  by  the 
peritoneum ;  while  in  front  the  peritoneum  is  reflected  from  the 
upper  part  of  the  cervix  of  the  uterus  to  the  posterior  surface  of  the 
bladder.  On  each  side  it  gives  attachment  superiorly  to  the  broad 
ligaments  of  the  uterus;  and  inferiorly  to  the  pelvic  fascia,  and  to 
the  levatores  ani. 

The  Mucous  membrane  presents  a  number  of  transverse  papillce 
or  ruga;  upon  its  upper  and  lower  surfaces,  which  extend  outwards 
on  each  side  from  a  middle  raphe.  The  transverse  papilloe  and 
raphe  are  more  apparent  upon  the  upper  than  upon  the  lower 
surface,  and  the  two  raphe  are  called  the  columns  of  the  vagina. 
The  mucous  membrane  is  covered  by  a  thin  cuticular  epithelium, 
which  is  continued  from  the  labia,  and  terminates  by  a  fringed 
border  at  about  the  middle  of  the  cervix  uteri. 

The  Middle  or  erectile  layer  consists  of  erectile  tissue  enclosed 


CONTEiSTS  OF  FEMALE  PELVIS. 


573 


between  two  layers  of  fibrous  membrane;  this  la3'er  is  thickest 
near  the  commencement  of  the  vagina,  and  becomes  gradually- 
thinner  as  it  approaches  the  uterus. 

The  External,  or  dartoid  layer  of  the  vagina,  serves  to  connect 
it  to  the  surrounding  viscera.  Thus,  it  is  very  closely  adherent  to 
the  under  surface  of  the  bladder,  and  drags  that  organ  down  with 
it  in  prolapsus  uteri.  To  the  rectum  it  is  less  closely  connected, 
and  that  intestine  is  therefore  less  frequently  affected  in  prolapsus. 

UTERUS. 

The  Uterus  is  a  flattened  organ  of  a  pyriform  shape,  having  the 
base  directed  upwards  and  forwards,  and  the  apex  downwards  and 
backwards  in  the  line  of  the  axis  of  the  inlet  of  the  pelvis,  and 
forming  a  considerable  angle  with  the  course  of  the  vagina.     It  is 

Fig.  197. 


Fig.  197.  A  side  view  of  the  viscera  of  the  female  pelvis.  1.  The  symphysis  pubis; 
to  the  upper  part  of  which  the  tendon  of  the  rectus  muscle  is  attached.  2.  The  ab- 
dominal parietes.  3.  The  collection  of  fat,  forming  the  projection  of  themons  Veneris. 
4.  The  urinary  bladder.  5.  The  entrance  of  the  left  ureter.  6.  The  canal  of  the 
urethra,  converted  into  a  mere  fissure  by  the  contraction  of  its  walls.  7.  The  meatus 
nrinarius.  8.  The  clitoris,  with  its  prasputium,  divided  through  the  middle.  9.  The 
left  nympha,  10.  The  left  labium  majus.  11.  The  meatus  of  the  vagina,  narrowed 
by  the  contraction  of  its  sphincter.  12.  The  canal  of  the  vagina,  upon  which  ths 
transverse  rugoe  are  apparent.  13.  The  thick  wall  of  separation  between  the  base  of 
the  bladder  and  the  vagina.  14,  The  wall  of  separation  between  the  vagina  and  the 
rectum.  15..  The  perineum.  16.  The  os  uteri.  17.  Its  cervix.  18.  The  fundus 
uteri.  The  cavitas  uteri  is  seen  along  the  centre  of  the  organ.  19.  The  rectum, 
showing  the  disposition  of  its  mucous  membrane.  20.  The  anus.  21.  The  upper  part 
of  the  rectum,  invested  by  the  peritoneum,  22.  The  rectouterine  fold  of  the  peri- 
toneum, just  above  the  figure.  23.  The  utero-vesical  fold.  24.  The  reflection  of  the 
peritonevim,  from  the  apex  of  the  bladder,  upon  the  (rachus  to  ihe  internal  surface  of 
the  abdominal  parietes,  25.  The  last  lumbar  vertebra.  26.  Tlie  sacrum.  27.  The 
coccyx. 


574  STRUCTDKE  OF  UTERUS. 

convex  on  its  posterior  surface,  and  somewhat  flattened  upon  its 
anterior  aspect.  In  tiie  unimpregnaled  state  it  is  about  three  inches 
in  length,  two  in  breadth  across  its  broadest  part,  and  one  in  thick- 
ness, and  is  divided  into  fundus,  body,  cervix,  and  os  uteri.  At  the 
period  of  puberty  the  uterus  weighs  about  one  ounce  and  a  half  ; 
after  parturition  from  two  to  three  ounces;  and  at  the  ninth  month 
of  utero-gestation  from  two  to  four  pounds. 

The  Fundus  and  body  are  enclosed  in  a  duplicature  of  perito- 
neum, which  is  connected  with  the  two  sides  of  the  pelvis,  and 
forms  a  transverse  septum  between  the  bladder  and  rectum.  The 
folds  formed  by  this  duplicature  of  peritoneum  on  either  side  of  the 
organ  are  the  broad  ligaments  of  the  uterus.  The  cervix  is  the 
lower  poriion  of  the  organ;  it  is  distinguished  from  the  body  by  a 
well-marked  constriction  ;  to  its  upper  part  is  attached  the  upper 
extremity  of  the  vagina,  and  at  its  extremity  is  an  opening  which 
is  nearly  round  in  the  virgin,  and  transverse  after  parturition — the 
OS  uteri — bounded  before  and  behind  by  two  labia  ;  the  anterior 
labium  being  the  most  thick,  and  the  posterior  somewhat  the  longest. 
The  opening  of  the  os  uteri  is  of  considerable  size,  and  is  named 
the  orificium  uteri  externum  ;  the  canal  then  becomes  narrowed, 
and  at  the  upper  end  of  the  cervix  is  constricted  into  a  smaller 
opening — the  orificium  internum.*  At  this  point  the  canal  of  the 
cervix  expands  into  the  shallow  triangular  cavity  of  the  uterus,  the 
inferior  angle  corresponding  with  the  orificium  internum,  and  the 
two  superior  angles,  which  are  funnel-shaped  and  represent  the 
original  bicornule  condition  of  the  organ,  with  the  commencement 
of  the  Fallopian  tubes.  In  the  canal  of  the  cervix  uteri  are  two 
or  three  longitudinal  folds  to  which  numerous  oblique  folds  converge 
so  as  to  give  the  idea  of  branches  from  the  stem  of  a  tree ;  hence 
this  appearance  has  been  denominated  the  arbor  vitcs  uterina.  Be- 
tween these  folds,  and  around  the  os  uteri,  are  numerous  mucous 
follicles.  It  is  the  closure  of  the  mouth  of  one  of  these  follicles, 
and  the  subsequent  distension  of  the  follicle  with  its  proper  secre- 
tion, that  occasions  those  vesicular  appearances  so  often  noticed 
within  the  mouth  and  cervix  of  the  uterus,  called  the  ovula  of 
JVaboth. 

Structure. — The  uterus  is  composed  of  three  tunics  ;  of  an  external 
or  serous  coat  derived  from  the  peritoneum,  which  constitutes  the 
duplicatures  on  each  side  of  the  organ  called  the  broad  ligaments; 
of  a  middle  or  muscular  coal,  which  gives  thickness  and  bulk  to  the 
uterus;  and  of  an  internal  or  mucous  membrane,  which  lines  its  in- 
terior, and  is  continuous  on  the  one  hand  with  the  mucous  lining  of 
the  Fallopian  tubes,  and  on  the  other  with  that  of  the  vagina.  In 
the  unimpregnaled  state  the  muscular  coat  is  exceedingly  condensed 
in  texture,  offers  considerable  resistance  to  section  with  the  scalpel, 
and  appears  to  be  composed  of  white  fibres  inextrir'.al)ly  interlaced 
and  mingled  with  blood-vessels.     In  the  impregnated  uterus  the 

*  The  orificium  internum  is  not  unfrcqucntly  obliterated  in  old  persons.     Indeed 
tliis  obliteration  is  so  common,  as  to  have  induced  Mayer  to  regard  it  as  normal. 


STRUCTURE  OF  UTERUS. 


575 


fibres  are  of  large  size  and  distinct,  and  are  disposed  in  two  layers, 
superficial  and  deep.  The  superficial  layer  consists  of  fibres  which 
pursue  a  vertical  direction,  some  being  longitudinal  and  others 
olWique.     The  longitudinal  fibres  are  found  principally  upon   the 

Fig.  198. 


Fig.  199. 


middle  line,  forming  a  thin  plane  upon  the  anterior  and  posterior 
face  of  the  organ  and  upon  its  fundus.  The  oblique  fibres  occupy 
chiefly  the  sides  and  fundus.  At 
the  angles  of  the  uterus  the  fibres 
of  the  superficial  layer  are  con- 
tinued outwards  upon  the  Fallopian 
tubes,  and  into  the  round  ligaments 
and  the  ligaments  of  the  ovaries. 
The  deej)  layer  consists  of  two  hol- 
low cones  of  circular  fibres  having 
their  apex  at  the  openings  of  the 
Fallopian  tubes,  and  by  their  bases 
intermingling  with  each  other  on 
the  body  of  the  organ.  These 
fibres  are  continuous  with  the  deep 
muscular  layer  of  the  Fallopian 
tubes,  and  indicate  the  primitive 
formation  of  the  uterus  by  the 
blending  of  these  two  canals. 
Around  the  cervix  uteri  the  mus- 
cular fibres  assume  a  circular  form 
interlacing  with  and  crossing  each 
other  at  acute  angles.  The  mucous 
membrane  is  provided  with  a  co- 
lumnar ciliated  epithelium,  which 
extends  from  the  middle  of  the  cervix  uteri  to  the  extremities  of  the 
Fallopian  tubes. 

Fig.  198.  Uterus.     Round  ligaments,  Fallopian  tubes,  and  peritoneal  investment. 
Fig.  199.  Section  of  the  uterus  (transverse).     The  two  bristles  are  introduced  into  the 
orifices  of  the  Fallopian  tubes. 


576  FALLOPIAN  TUBES. 

Vessels  and  JVerves. — The  Arteries  of  the  uterus  are  the  uterine 
from  the  internal  iliac,  and  the  spernnatic  from  the  aorta.  The 
veins  are  very  large  and  remarkable ;  in  the  impregnated  uterjas 
they  aTe  called  sinuses,  and  consist  of  canals  channeled  through  the 
substance  of  the  organ,  being  merely  lined  by  the  internal  membrane 
of  the  veins.  They  terminate  on  each  side  of  the  uterus  in  the 
uterine  plexuses.     The  lymphatics  terminate  in  the  lumbar  glands. 

The  Nerves  are  derived  from  the  hypogastric  and  spermatic 
plexuses,  and  from  the  sacral  plexus. 

The  Appendages  of  the  uterus  are  enclosed  by  the  lateral  duplica- 
tures  of  peritoneum,  called  the  broad  ligaments.  They  are  the  Fal- 
lopian tubes  and  ovaries. 

FALLOPIAN    TUBES. 

The  Fallopian^  tubes  or  oviducts,  the  uterine  trumpets  of  the 
French  writers,  are  situated  in  the  upper  border  of  the  broad  liga- 
ments, and  are  connected  with  the  superior  angles  of  the  uterus. 
They  are  somewhat  trumpet-shaped,  being  much  smaller  at  the 
uterine  than  at  the  free  extremity,  and  narrower  in  the  middle  than 
at  either  end.  Each  tube  is  about  four  or  five  inches  in  length,  and 
more  or  less  flexuous  in  its  course.  The  canal  of  the  Fallopian 
tube  is  exceedingly  minute,  its  inner  extremity  opens  by  means  of 
the  ostium  uterinum  into  the  upper  angle  of  the  cavity  of  the  uterus, 
and  the  opposite  end  into  the  cavity  of  the  peritoneum.  The  free 
or  expanded  extremity  of  the  Fallopian  tube  presents  a  double  and 
sometimes  a  triple  series  of  small  processes  or  fringes  which  sur- 
round the  margin  of  the  trumpet  or  funnel-shaped  opening,  the 
ostium  abdominale.  This  fringe-like  appendage  to  the  end  of  the 
tube  has  gained  for  it  the  appellation  of  the  fimbriated  extremity; 
and  the  remarkable  manner  in  which  this  circular  fringe  applies 
itself  to  the  surface  of  the  ovary  during  sexual  excitement,  the  ad- 
ditional title  of  morsus  diaboli.  One  of  these  processes,  longer  than 
the  rest,  or,  according  to  Cruveilhier,  a  distinct  ligamentous  cord, 
is  attached  to  the  distal  end  of  the  ovary,  and  serves  to  guide  the 
tube  in  its  seizure  of  that  organ. 

The  Fallopian  tube  is  composed  of  three  tunics,  an  external  and 
loose  investment  derived  from  the  peritoneum;  a  middle  or  muscular 
coat  consisting  of  circular  [internal]  and  longitudinal  [external] 
fibres,  continuous  with  those  of  the  uterus  ;  and  an  internal  or  lining 
mucous  membrane,  which  is  continuous  on  the  one  hand  with  the 
mucous  membrane  of  the  uterus,  and  at  the  opposite  extremity  with 
the  peritoneum.  In  the  minute  canal  of  the  tube  the  mucous  mem- 
brane is  thrown  into  longitudinal  folds  or  rugae,  which  indicate  the 
adaptation  of  the  tube  to  dilatation. 

*  Gabriel  Fallopiufl,  a  nobleman  of  Modena,  was  one  of  the  founders  of  modern  ana- 
tomy. He  was  Professor  at  Ferrara,  tlien  at  Pisa,  and  afterwards  succeeded  Vesalius 
at  Padua.  His  principal  observations  are  collected  in  a  worii,  "  Obscrvationes  Ana- 
tomicffl,"  which  he  pulilished  in  15G1. 


OVARIES — EXTERNAL  ORGANS.  577 


OVARIES. 

The  Ovaries  are  two  oblono;  flattened  and  oval  bodies  of  a  whitish 
colour,  situated  in  the  posterior  layer  of  peritoneum  of  the  broad 
ligannents.  They  are  connected  to  the  upper  angles  of  the  uterus 
at  each  side  by  nneans  of  a  rounded  cord,  consisting  chiefly  of  mus- 
cular fibres  derived  from  the  uterus, — tlie  ligament  of  the  ovary. 

In  structure  the  ovary  is  composed  of  a  cellulo-fibrous  parenchyma 
or  stroma,  traversed  by  blood-vessels,  and  enclosed  in  a  capsule 
consisting  of  three  layers;  avascular  layer,  which  is  situated  most 
internally  and  sends  processes  inwards  towards  the  interior  of  the 
organ;  a  middle  or  fibrous  layer  of  considerable  density,  and  an 
external  investment  of  peritoneum.  In  the  cells  of  the  stroma  of  the 
ovary  the  small  vesicles  or  ovisacs  of  the  future  ova,  the  Graafian 
vesicles,  as  they  have  been  termed,  are  developed.  There  are  usu- 
ally about  fifteen  fiilly  formed  Graafian  vesicles  in  each  ovary;  but 
Dr.  Martin  Barry  has  shown  that  countless  numbers  of  microscopic 
ovisacs  exist  in  the  parenchyma  of  the  organ,  and  that  very  few 
out  of  these  are  perfected  so  as  to  produce  ova. 

After  conception  a  yellow  spot,  the  corpus  luteum,  is  found  in  one 
or  both  ovaries.  The  corpus  luteum  is  a  globular  mass  of  yellow, 
spongy  tissue,  traversed  by  while  cellular  bands,  and  containing  in 
its  centre  a  small  cavity,  more  or  less  obliterated,  which  was  origi- 
nally occupied  by  the  ovum.  The  interior  of  the  cavity  is  lined  by 
a  puckered  membrane,  the  remains  of  the  ovisac.  In  recent  corpora 
lutea  the  opening  by  which  the  ovum  escaped  from  the  ovisac 
through  the  capsule  of  the  ovary  is  distinctly  visible;  when  closed, 
a  small  cicatrix  may  be  seen  upon  the  surface  of  the  ovary  in  the 
situation  of  the  opening.  A  similar  appearance  to  the  preceding, 
but  of  smaller  size,  and  without  a  central  cavity,  is  sometimes  met 
.with  in  the  ovaries  of  the  virgin, — this  is  a  false  corpus  luteum. 

Vessels  and  Nerves. — The  Arteries  of  the  ovaries  are  the  sper- 
matic.    Its  nerves  are  derived  from  the  spermatic  plexus. 

The  Round  ligaments  are  two  muscular  and  fibrous  cords  situated 
between  the  layers  of  ihe  broad  ligaments,  and  extending  from  the 
upper  angles  of  the  uterus,  and  along  the  spermatic  canals  to  the 
labia  majora,  in  which  they  are  lost.  They  are  accompanied  by  a 
small  artery,  by  several  filaments  of  the  spermatic  plexus  of  nerves, 
and  b}'  a  plexus  of  veins.  The  latter  occasionaly  become  varicose, 
and  form  a  small  tumour  at  the  external  abdominal  ring,  which  has 
been  mistaken  for  inguinal  hernia.  The  round  ligaments  serve  to 
retain  the  uterus  in  its  proper  position  in  the  pelvis,  and  during  utero- 
gestation  to  draw  the  anterior  surface  of  the  organ  against  the  ab- 
dominal parietes. 

EXTERNAL  ORGANS  OF  GENERATION. 

The  female  organs  of  generation  are  divided  into  the  internal  and 
external ;  the  internal  are  contained  within  the  pel\is,  and  have  been 
already  described, — they  are  the  vagina,  uterus,  ovaries,  and  Fallo- 

49 


578 


LABIA CLITORIS. 


Fig.  200. 


plan  tubes.  The  external  organs  are  the  naons  Veneris,  labia  ma- 
jora,  labia  minora,  clitoris,  meatus  urinarius,  and  the  opening  of  the 
vagina. 

The  Mons  Veneris  is  the  eminence  of  integument,  situated  upon 
the  front  of  the  os  pubis.  Its  cellular  tissue  is  loaded  with  adipose 
substance,  and  the  surface  covered  with  hairs. 

The  Labia  majora  are  two  large  longitudinal  folds  of  integument, 
consisting  of  fat  and  loose  cellular  tissue.  They  enclose  an  elliptical 
fissure,  the  common  urino-sexual  opening  or  vulva.  The  vulva  re- 
ceives the  inferior  opening  of  the  urethra  and  vagina,  and  is  bounded 
anteriorly  by  the  commissura  superior,  and  posteriorly  by  the  com- 
missura  inferior.  Stretching  across  the  posterior  commissure  is  a 
small  tran§verse  fold,  \he  frcEnulum  labinrum  or  fourchette,  which  is 
ruptured  during  parturition,  and  immediately  within  this  fold  is  a 
small  cavity,  the  fossa  navicularis.  The 
breadth  of  the  perineum,  is  measured  from 
the  posterior  commissure  to  the  margin  of 
the  anus,  and  is  usually  not  more  than  an  inch 
across.  The  external  surface  of  the  labia 
is  covered  with  hairs ;  the  inner  surface  is 
smooth,  and  lined  by  mucous  membrane, 
which  contains  a  number  of  sebaceous  fol- 
licles, and  is  covered  by  a  thin  cuticular 
epithelium.  The  use  of  the  labia  majora  is 
to  favour  the  extension  of  the  vulva  during 
parturition;  for  in  the  passage  of  the  head  of 
the  foetus  the  labia  are  completely  unfolded 
W.  and  effaced. 

The  Labia  minora,  or  nymp/icE  are  two 
smaller  folds  situated  within  the  labia  majora.  Superiorly  they  are 
divided  into  two  processes,  which  surround  the  glans  clitoridis,  the 
superior  fold  forming  the  pra3putium  clitoridis,  and  the  inferior  its 
fraenulum.  Inferiorly,  they  diminish  gradually  in  size,  and  are  lost 
on  the  sides  of  the  opening  of  the  vagina.  The  nymphse  consist  of 
mucous  membrane,  covered  by  a  thin  cuticular  epithelium.  They 
are  provided  with  a  number  of  sebaceous  follicles,  and  contain,  in 
their  interior,  a  layer  of  erectile  tissue. 

The  Clitoris  is  a  small  elongated  organ  situated  in  front  of  the  os 
pubis,  and  supported  by  a  suspensory  ligament.  It  is  formed  by  a 
small  body,  which  is  analogous  to  the  corpus  cavernosum  of  the 
penis,  and,  like  it,  arises  from  the  ramus  of  the  os  pubis  and  ischium 
on  each  side,  by  two  crura.  The  extremity  of  the  clitoris  is  called 
its  glans.  It  is  composed  of  erectile  tissue,  enclosed  in  a  dense 
layer  of  fibrous  meinbrane,  and  is  susceptible  of  erection.  Like  the 
penis,  it  is  provided  with  two  small  muscles,  the  erectores  clitoridis. 
At  about  an  inch  beneath  the  clitoris  is  tlie  entrance  of  the  vagina, 
an  elliptical  opening,  marked  by  a  projecting  margin.  The  entrance 
to  the  vagina  is  closed  in  the  virgin  by  a  membrane  of  a  semilunar 
form,  which  is  stretched  across  the  opening;  this  is  the  hymen. 


MAMMARY  GLANDS.  579 

Sometimes  the  membrane  forms  a  complete  septum,  and  gives  rise 
to  great  inconvenience  by  preventing  tlie  escape  of  the  menstrual 
effusion.  It  is  then  called  an  imperforate  hymen.  The  hymen  must 
not  be  considered  a  necessary  accompaniment  to  virginity,  for  its 
existence  is  very  uncertain.  When  present  it  assumes  a  variety  of 
appearances:  it  may  be  a  membranous  fringe,  with  a  round  open- 
ing in  the  centre,  or  a  semilunar  fold,  leaving  an  opening  in  front; 
or  a  transverse  septum,  having  an  opening  both  in  front  and  behind  ; 
or  a  vertical  band  with  an  opening  at  either  side. 

The  rupture  of  the  hymen  or  its  rudimentary  existence,  gives  rise 
to  the  appearance  of  a  fringe  of  papillae  around  the  opening  of  the 
vagina:  these  are  called  caranculce  inyrliformes. 

The  triangular  smooth  surface  between  the  clitoris  and  the  en- 
trance of  the  vagina,  which  is  bounded  on  each  side  by  the  upper 
portions  of  the  nymphae,  is  the  vestibule. 

At  the  upper  angle  of  the  vagina  is  an  elevation  formed  by  the 
projection  of  the  upper  wall  of  the  canal,  and  analogous  to  the  bulb 
of  the  urethra  of  the  male :  and  immediately  in  front  of  this  tubercle, 
and  surrounded  by  it,  is  the  opening  of  the  urethra,  the  meatus 
urinarius. 

MAMMARY     GLANDS. 

The  Mammcs  are  situated  in  the  pectoral  region;  and  are  separated 
from  the  pectoralis  major  muscle  by  a  thin  layer  of  superficial  fascia. 
They  exist  in  the  male  as  well  as  in  the  female,  but  in  a  rudimentary 
state,  unless  excited  into  growth  by  some  peculiar  action,  such  as 
the  loss  or  atrophy  of  the  testes. 

Their  base  is  somewhat  elliptical,  the  long  diameter  correspond- 
ing with  the  direction  of  the  fibres  of  the  pectoralis  major  muscle. 
The  left  mamma  is  generally  a  little  larger  than  the  right. 

Near  the  centre  of  the  convexity  of  each  mamma  is  a  small  pro- 
jection of  the  integument,  called  the  nipple,  which  is  surrounded  by 
an  areola  having  a  coloured  tint.  In  the  female  before  impregna- 
tion, the  colour  of  the  areola  is  a  delicate  pink ;  after  impregnation 
it  assumes  a  brownish  hue  which  deepens  in  colour  as  pregnancy 
advances  ;  and  after  the  birth  of  a  child,  tlie  brownish  tint  continues 
through  life. 

The  areola  is  furnished  with  a  considerable  number  of  sebaceous 
follicles,  which  secrete  a  peculiar  fatty  substance  for  the  protection 
of  the  delicate  integument  around  the  nipple.  During  suckling  these 
follicles  are  very  much  increased  in  size,  and  have  the  appearance 
of  small  pimples  projecting  from  the  skin.  At  this  period  they 
serve  by  their  increased  secretion  to  defend  the  nipple  and  areola 
from  the  excoriating  action  of  the  saliva  of  the  infant. 

In  Structure,  the  mamma  is  a  conglomerate  gland,  and  consists 
of  lobes,  which  are  held  together  by  a  dense  and  firm  cellular  tissue ; 
the  lobes  are  composed  of  lobules;  and  the  lobules,  of  minute  caDcal 
vesicles,  the  ultimate  terminations  of  the  excretory  ducts. 

The  excretory  ducts   (tubuli   lactiferi),  from  ten  to  fifteen   in 


580  NERVES  OF  MAMM^. 

number,  commence  by  small  openings  at  the  apex  of  the  nipple, 
and  pass  inwards,  parallel  with  each  other,  towards  the  central 
part  of  the  gland,  where  they  form  dilatations  (ampullae)  and  give 
off  numerous  branches  to  ramify  through  the  gland  to  their  ultimate 
terminations  in  the  minute  lobules. 

The  ducts  and  csecal  vesicles  are  lined  throughout  by  a  mucous 
memjbrane,  which  is  continuous  at  the  apex  of  the  nipple  with  the 
integument. 

In  the  nipple  the  excretory  ducts  are  surrounded  by  a  tissue  ana- 
logous to  the  dartos  of  the  scrotum,  to  which  the  power  of  erectility 
of  the  nipple  seems  due.  There  is  no  appearance  of  any  structure 
resembling  erectile  tissue. 

Vessels  and  Nerves. — The  mammss  are  supplied  with  arteries 
from  the  thoracic  branches  of  the  axillary,  from  the  intercostals, 
and  from  the  internal  mammary. 

The  Lymphatics  follow  the  border  of  the  pectoralis  major  to  the 
axillary  glands. 

The  Nerves  are  derived  from  the  thoracic  and  intercostals. 


CHAPTER   XI.  • 

ANATOMY  OF  THE  FCETUS. 

The  medium  weight  of  a  child  of  the  full  period,  at  birth,  is 
seven  pounds;  and  its  length  nineteen  inches.  The  head  is  of 
large  size,  and  lengthened  from  before  backwards;  the  face  small. 
The  upper  extremities  are  greatly  developed,  and  the  thorax 
expanded  and  full.  The  upper  part  of  the  abdomen  is  large,  from 
the  great  size  of  the  liver;  the  lower  part  is  small  and  conical. 
And  the  lower  extremities  are  very  small  in  proportion  to  the  rest 
of  the  body.  The  external  genital  organs  are  very  large,  and  fully 
developed. 

Osseous  System. — The  developement  of  the  osseous  system  has 
been  treated  of  in  the  first  chapter.  The  ligamentous  system  pre- 
sents no  peculiarity  deserving  of  remark. 

Muscular  System. — The  muscles  of  the  foetus  at  birth  are  large 
and  fully  formed.  They  are  of  a  lighter  colour  than  those  of  the 
adult,  and  of  a  softer  texture.  The  transverse  strias  upon  the  fibres 
of  animal  life  are  not  distinguishable  until  the  sixth  month  of 
foetal  life. 

Vascular  System. — The  circulating  system  presents  several 
peculiarities;  Istly,  In  the  heart;  there  is  a  communication  be- 
tween the  two  auricles  by  mean*  o?  ihe  foramen  ovale.  2dly,  In  the 
arterial  system  ;  there  is  a  communication  between  the  pulmonary 
artery  and  descending  aorta,  by  means  of  a  large  trunk — the 
ductus  arteriosus.  3dly,  Also  in  the  arterial  system;  the  internal 
iliac  arteries,  under  the  name  of  hypogastric  and  umbilical,  are 
continued  from  the  foetus  to  the  placenta,  to  which  they  return  the 
blood  which  has  circulated  in  the  system  of  the  foetus.  4thly,  In 
the  venous  system ;  there  is  a  communication  between  the  umbili- 
cal vein  and  the  inferior  cava,  called  the  ductus  venosus. 

FCETAL    circulation. 

The  pure  blood  is  brought  from  the  placenta  by  the  umbilical 
vein.  The  umbilical  vein  passes  through  the  umbilicus  and  enters 
the  liver,  where  it  divides  into  several  branches,  which  may  be 
arranged  under  three  heads: — Istly,  two  or  three  of  which  are  dis- 
triluited  to  the  left  lobe.  2dly,  A  single  branch  which  communi- 
cates with  the  portal  vein  in  the  transverse  fissure,  and  supplies  the 
right  lobe.    3dly,  A  large  branch,  the  ductus  venosus,  which  passes 

49* 


582 


FCETAL  CIRCULATION. 


\J  u 


directly  backwards  and  joins  the 
inferior  cava.  In  the  inferior 
cava  the  pure  blood  becomes 
mixed  with  that  which  is  return- 
ing from  the  lower  extremities, 
and  is  carried  througrh  the  right 
auricle,  guided  by  the  Eustachian 
valve,  and  through  the  foravien 
ovale  into  the  left  auricle.  From 
the  left  auricle  it  passes  into  the 
left  ventricle,  and  from  the  left 
ventricle  into  the  aorta,  whence 
it  is  distributed,  by  means  of  the 
carotid  and  subclavian  arteries, 
principally  to  the  head  and  upper 
extremities.  From  the  head  and 
upper  extremities,  the  impure  blood 
is  returned  by  the  superior  vena 
cava  to  the  right  auricle.  From 
the  right  auricle,  it  is  propelled 
into  the  right  ventricle ;  and 
from  the  right  ventricle  into  the 
pulmonary  artery.  In  the  adult, 
the  blood  would  now  be  circu- 
lated through  the  lungs,  and  oxy- 
genated ;  but  in  the  foetus  the 
lungs  are  solid,  and  almost  imper- 
vious. Only  a  small  quantity  of 
the  blood  passes  therefore  into  the 
lungs ;  the  greater  part  rushes 
thi'ough  the  ductus  arteriosus,  into 
the  commencement  of  the  descend- 
ing aorta. 


Fig-.  201.  The  fcetal  circulation.  1.  The  umbilical  cord,  consisting  of  the  umbilical 
vein  and  two  umbilical  arteries  ;  proceeding  from  the  placenta  (2).  3.  The  umbilical 
vein  dividing-  into  three  branches  ;  two  (4,  4)  to  be  distributed  to  the  liver ;  and  one  (.5), 
the  ductus  venosus,  which  enters  the  inferior  vena  cava  (6).  7.  The  portal  vein  re- 
turning the  blood  from  the  intestines,  and  uniting  -with  tlie  right  hepatic  branch.  8. 
The  rigiit  auricle  ;  the  course  of  the  blood  is  denoted  by  the  arrow,  proceeding  from  8 
to  9,  the  left  auricle.  10.  The  left  ventricle  ;  the  blood  following  the  arrow  to  the  arch 
of  the  aorta  (11),  to  be  distributed  through  the  branches  given  off  by  the  arch  to  the 
head  and  upper  extremities.  The  arrows  12  and  13,  represent  the  return  of  the  blood 
from  the  head  and  upper  extremities  through  tiie  jugular  and  subclavian  veins,  to  the 
superior  vena  cava  (14),  to  the  right  auricle  (8),  and  in  the  course  of  the  arrow  tln-ough 
the  right  ventricle  (15),  to  the  [)u!monary  artery  (16).  17.  The  ductus  arteriosus, 
which  appears  to  be  a  proper  continuation  of  the  pulmonary  artery,  the  offsets  at  each 
side  are  the  right  and  left,  pulmonary  artery  cut  off;  these  are  of  extremely  small  size 
aa  compared  with  tiic  ductus  arteriosus.  The  ductus  arteriosus  joins  the  descending 
aorta  (18,  18),  which  divides  into  the  common  iliacs,  and  these  into  the  internal  iliacs, 
which  become  the  umbilical  arteries  (I!)),  and  return  the  blond  along  the  umbilical 
cord  to  the  placenta;  while  the  other  divisions,  the  external  iliacs  (20),  are  conlinucd 
into  the  lower  extremities.  The  arrows  at  the  terminaiion  of  these  vessels  mark  the 
return  of  the  venous  blood  by  tfie  veins  to  the  inferior  cava. 


FCETAL  CIRCULATION.  583 

Passing  along  the  aorta,  a  small  quantity  of  the  in^pure  blood  is 
distributed  by  the  external  iliac  arteries  to  the  lower  extremities; 
the  greater  portion  enters  the  internal  iliacs,  and  is  carried  on- 
wards by  the  side  of  the  bladder,  and  upwards  along  the  anterior 
•wall  of  the  abdomen,  and  throngh  the  umbilicus,  under  the  name  of 
umbilical  arteries,  to  the  placenta,  to  which  they  return  the  blood 
that  has  been  circulated  through  the  system  of  the  foetus. 

From  a  careful  consideration  of  this  circulation,  we  shall  per- 
ceive—  1st.  That  the  pure  blood  from  the  placenta  is  distributed  in 
considerable  quantity  to  ihe  liver,  before  entering  the  general  circu- 
lation. Hence  arises  the  abundant  nutrition  of  that  organ,  and  its 
enormous  size  in  comparison  with  the  other  viscera. 

2dly.  That  the  right  auricle  is  the  scene  of  meeting  of  a  double 
current ;  the  one  coming  from  the  inferior  cava,  the  other  from  the 
superior,  and  that  they  must  cross  each  other  in  their  respective 
course.  Hovv  this  crossing  is  effected  the  theorist  will  wonder ;  not 
so  the  practical  anatomist;  for  a  cursory  examination  of  the  foetal 
heart  will  show,  1.  That  the  direction  of  entrance  of  the  two  vessels 
is  so  opposite,  that  they  may  discharge  their  currents  through  the 
same  cavity  without  admixture.  2.  That  the  inferior  cava  opens 
almost  directly  into  the  left  auricle.  3.  That  by  the  aid  of  the 
Eustachian  valve,  the  current  in  the  inferior  cava  will  be  almost 
entirely  excluded  from  the  right  ventricle. 

3dly.  That  the  blood  which  circulates  through  the  arch  of  the 
aorta  comes  directly  from  the  placenta  ;  and,  although  mixed  with 
impure  blood  of  the  inferior  cava,  yet  is  propelled  in  so  great 
abundance  to  the  head  and  upper  extremities,  as  to  provide  for  the 
increased  nutrition  of  those  important  parts,  and  prepare  them,  by 
their  greater  size  and  developement,  fur  the  functions  which  they 
are  required  to  perform  at  the  instant  of  birth. 

4thly.  That  the  blood  circulating  in  the  descending  aorta  is  very 
impure,  being  obtained  principally  from  the  returning  current  in  the 
superior  cava  ;  a  small  quantity  only  being  derived  rt-om  the  left 
ventricle.  Yet  is  it  from  this  impure  blood  that  the  nutrition  of  the 
lower  extremities  is  provided.  Hence  we  are  not  surprised  at  their 
insignificant  developement  at  birth,  while  we  admire  the  providence 
of  nature,  that  directs  the  nutrient  current  in  abundance  to  the 
organs  of  sense,  of  prehension,  and  of  deglutition,  so  necessary 
even  at  the  mstant  of  birth  to  the  safety  and  welfare  of  the  crea- 
ture. 

After  birth,  the  foramen  ovale  becomes  gradually  closed  by  a 
membranous  layer,  \\hich  is  developed  from  the  margins  of  the 
opening  from  below  upwards,  and  completely  separates  the  two 
auricles.  The  situation  of  the  foramen  is  seen  in  the  adult  heart, 
upon  the  septum  auriculorum,  and  is  called  the  fossa  ovalis ;  the 
projecting  margin  of  the  opening  forms  the  anmdus  ovalis. 
.  As  soon  as  the  lungs  have  become  inflated  by  the  first  spasmodic 
act  of  inspiration,  the  blood  of  the  pulmonary  artery  rushes  through 
its  right  and  left  branches  into  the  lungs,  to  be  returned  to  the  left 


584  ORGANS  OF  SENSE THYROID  GLAND. 

auricle  by  the  pulmonary  veins.  Thus  the  pulmonary  circulation 
is  established.  Then  the  ductus  arteriosus  contracts,  and  degene- 
rates into  an  impervious  fibrous  cord,  serving  in  after  life  merely 
as  a  bond  of  union  between  the  left  pulmonary  artery  and  the  con- 
cavity of  the  arch  of  the  aorta. 

The  current  through  the  umbilical  cord  being  arrested,  the 
umbilical  arteries  likewise  contract  and  become  impervious,  and 
degenerate  into  the  umbilical  ligaments  of  the  bladder. 

The  Umbilical  vein  and  ductus  venosus,  also  deprived  of  their 
circulating  current,  become  reduced  to  fibrous  cords,  the  former 
forming  the  round  ligament  of  the  liver,  and  the  latter  a  fibrous 
band  which  may  be  traced  along  the  fissure  for  the  ductus  venosus 
to  the  inferior  vena  cava. 

Nervous  System. — The  brain  is  very  soft,  almost  pulpy,  and  has 
a  reddish  tint  throughout:  the  difference  between  the  white  and 
gray  substance  is  not  well  marked.  The  nerves  are  firm  and  well 
developed. 

ORGANS   or    SENSE. 

Eye. — The  eyeballs  are  of  large  size  and  well  developed  at  birth. 
The  pupil  is  closed  by  a  vascular  membrane  called  the  membrana 
jiupillaris,  which  disappears  at  about  the  seventh  month.  Some- 
times it  remains  permanently,  and  produces  blindness.  It  consists 
of  two  thin  membranous  layers,  between  which  the  ciliary  arteries 
are  prolonged  from  the  edge  of  the  iris,  and  form  arches  by  re- 
turning to  it  again,  without  anastomosing  with  those  of  the  opposite 
side. 

The  removal  of  the  membrane  takes  place  by  the  contraction  of 
their  loops  towards  the  edge  of  the  pupil.  The  capsule  of  the  lens 
is  extremely  vascular. 

Ear. — The  ear  is  remarkable  for  its  early  developement ;  the 
labyrinth  and  ossicula  auditus  are  ossified  at  an  early  period,  and 
the  latter  are  completely  formed  before  birth.  The  only  parts  re- 
maining incomplete  are  the  mastoid  cells,  and  the  meatus  auditorius. 
The  membrani  tympani  in  the  foetal  head  is  very  oblique,  occupying 
almost  the  basilar  surface  of  the  skull ;  hence  probably  arises  a  de- 
ficient acuteness  in  the  perception  of  sound.  It  is  also  extremely 
vascular. 

Nose. — The  sense  of  smell  is  very  imperfect  in  the  infant,  as  may 
be  inferred  from  the  small  capacity  of  the  nasal  fossss,  and  the 
non-developement  of  the  ethmoid,  sphenoid,  frontal,  and  maxillary 
sinuses. 

THyROIDGLA^D. 

The  Thyroid  gland  is  of  a  large  size  in  the  foetus,  and  is  developed 
by  two  lateral  halves,  which  approach  and  become  connected  at 
the  middle  line  so  as  to  constitute  a  single  gland.  It  is  doubtful 
whether  it  performs  any  especial  function  in  foetal  life. 


THYMUS  GLAND. 


585 


THYMUS    GLAND. 

The  Thymus  gland*  consists  "of  a  thoracic  and  a  cervical  por- 
tion on  each  side.  The  former  is  situated  in  the  anterior  mediasti- 
nuni,  and  the  latter  is  placed  in  the  neck  just  above  the  first  bone  of 
the  sternum,  and  behind  the  sterno-hyoidei  and  sterno-thyroidei 
muscles."  It  extends  upwards  from  the  fourth  rib  as  high  as  the 
thyroid  gland,  resting  upon  the  pericardium,  and  separated  from  the 
arch  of  the  aorta  and  great  vessels  by  the  thoracic  fascia  in  the 
chest,  and  lying  on  each  side  of  the  trachea  in  the  neck. 

Although  described  usually  as  a  single  gland,  it  consists  actually 
of  two  lateral,  almost  symmetrical  glands,  connected  with  each 
other  by  cellular  tissue  only,  and  having  no  structural  communica- 
tion ;    they  may  therefore  be 

"  properly  called  a  right  and  Fig.  202. 

left  thymus  gland." 

Between  the  second  and 
third  months  of  embryo  exist- 
ence, the  thymus  is  so  small  as 
to  be  only  "just  perceptible;" 
and  continues  gradually  in- 
creasing with  the  growth  of 
the  foetus  until  the  seventh.  At 
the  eighth  month  it  is  large; 
but,  during  the  ninth,  it  under- 
goes a  sudden  change,  assumes 
a  greatly  increased  size,  and 
at  birth  weighs  240  grains. 
After  birth  it  contmues  to  en- 
large until  the  expiration  of  the  first  year,  when  it  ceases  to  grow, 
and  gradually  diminishes,  until  at  puberty  it  has  almost  disap- 
peared. 

The  thymus  is  a  conglomerate  gland,  being  composed  of  lobules 
disposed  in  a  spiral  form  round  a  central  cavity.  The  lobules  are 
held  together  by  a  firm  cellular  tissue  ("  I'eticulated,")  and  the  entire 
gland  is  enclosed  in  a  coarse  cellular  capsule. 

The  Lobules  are  very  numerous,  and  vary  in  size  from  that  of  the 
head  of  a  pin  to  a  moderate-sized  pea.  Each  lobule  contains  in 
its  interior  a  small  cavity,  or  "  secretory  cell,"  and  several  of  these 

Fig.  202.  A  section  of  the  thymus  gland  at  the  eighth  month,  showing  its  anatomy. 
This  figure,  and  the  succeeding,  were  drawn  from  two  of  Sir  Astley  Cooper's  beautiful 
preparations,  with  the  kind  permission  of  their  possessor.  The  references  were  made 
by  Sir  Astlcy's  own  hand.  1.  The  cervical  portions  of  the  gland  ;  the  independence  of 
the  two  lateral  glands  is  well  marked.  2.  Secretory  cells  seen  upon  the  cut  surface  of 
the  section  ;  these  are  observed  in  all  parts  of  the  section.  3,  3.  The  pores  or  openings 
of  the  secretory  cells  and  pouches,  ihey  are  seen  covering  the  whole  internal  surface  of 
the  great  central  cavity  or  reservoir.  The  continuity  of  the  reservoir  in  the  lower  or 
thoracic  portion  of  the  gland,  with  the  cervical  portion,  is  seen  in  the  figure. 

*  In  the  description  of  this  gland  I  have  adhered  closely  to  the  history  of  it  given  by 
our  great  authority  on  this  subiect.  Sir  Astley  Cooper,  in  his  beautiful  monograph  "On 
the  Anatomy  of  the  Thymus  Gland,"  1832. 


586 


STRUCTURE  OF  THrMUS. 


cells  open  into  a  small  "  pouch"  which  is  situated  at  their  base,  and 
leads  to  the  central  cavity,  the  "  resermir  of  the  thymus." 

The  Reseroior  is  lined  in  its  interior  by  a  vascular  mucous  mem- 
brane, which  is  raised  into  ridges  by  a  layer  of  Hgamentous  bands 
situated  beneath  it.  The  ligamentous  bands  pro- 
Fig.  203.  ceed  in  various  directions,  and  encircle  the  open 
mouths  (jjores)  ot^the  secretory  cells  and  pouches. 
This  ligamentous  layer  serves  to  keep  the  lobules 
together,  and  prevent  the  injurious  distension  of 
the  cavity. 

When  either  gland  is  carefully  unravelled  by 
removing  the  cellular  capsule  and  vessels,  and 
dissecting  away  the  reticulated  cellular  tissue, 
which  retains  the  lobules  in  contact,  the  re- 
^  servoir,  from  being  folded  in  a  serpentine  man- 
/  ner  upon  itself,  admits  of  being  drawn  out  into 
a  lengthened  tubular  cord*  around  which  the 
lobules  are  clustered  in  a  spiral  manner,  and 
resemble  knots  upon  a  cord,  or  a  string  of 
beads. 

The  reservoir,  pouches,  and  cells,  contain  a 
white  fluid  "  like  chyle,"  or  "  like  cream,  but 
with  a  small  admixture  of  red  globules." 

In  an  examination  of  the  thymic  fluid  which 
I  lately  made,  with  a  Powell  microscope  mag- 
nifying 500  times  linear  measure,  I  observed 
that  the  corpuscles  were  very  numerous,  smaller 
than  the  blood  corpuscles,  globular  and  oval  in 
form,  irregular  in  outline,  variable  in  size,  and 
provided  with  a  small  central  nucleus. 

In  the  human  foetus  this  fluid  has  been  found 
by  Sir  Astley  in  too  small  a  proportion  to  be 
submitted  to  chemical  analysis.  But  the  thy- 
mic fluid  of  the  foetal  calf,  which  exists  in  great  abundance,  gave 
the  following  analytical  results: — one  hundred  parts  of  the  fluid 
contained  sixteen  parts  of  solid  matter,  which  consisted  of, 

Incipient  fibrine. 

Albumen, 

Mucus,  and  muco-extractive  matter, 

Muriate  and  phosphate  of  potass, 

Phosphate  of  soda, 

Phosphoric  acid,  a  trace.f 

Fig.  203.  The  course  and  termination  of  the  "  absorbent  ducts"  of  the  thymus  of 
the  calf;  from  one  of  Sir  Astley  Cooper's  preparations.  1.  The  two  internal  jug-ular 
veins.  2.  The  superior  vena  cava.  3.  The  thoracic  duct,  dividing  into  two  brandies, 
which  reunite  previously  to  their  termination  in  the  root  of  the  left  jugular  vein. 
4.  The  two  thymic  ducts;  that  (iU  the  lofl  side  opens  into  the  tiioracic  duct,  and  tiiat 
on  the  right  into  the  root  of  the  right  jugular  vein. 

*  Sec  tlie  hnautiful  plates  in  Sir  Astley  (Iijoper's  work. 

t  This  analysis  was  conducted  by  Ur.  Uowlcr  of  Richmond. 


^ 


,  FCETAL  LU.\GS  AND  HEART.  587 

The  Arteries  of  the  thymus  gland  are  derived  from  the  internal 
mammary,  and  from  the  superior  and  inferior  thyroid. 

The  Veins  terminate  in  the  left  vena  innominate,  and  some  small 
branches  in  the  thyroid  veins. 

The  Nerves  are  very  minute,  and  are  derived  chiefly  through  the 
internal  mammary  plexus,  from  the  superior  thoracic  ganghon  of 
the  sympathetic.  Sir  Astley  Cooper  has  also  seen  a  branch  from 
the  junction  of  the  pneuraogastric  and  sympathetic  pass  to  the  side 
of  the  gland. 

The  Lymphatics  terminate  in  the  general  union  of  the  lymphatic 
vessels  at  the  junction  of  the  internal  jugular  and  subclavian  veins. 
Sir  Astley  Cooper  has  injected  them  only  once  in  the  human  foetus, 
but  in  the  calf  he  finds  two  large  lyntphatic  ducts,  ■whi(;h  commence 
in  the  upper  extremities  of  the  glands,  and  pass  downwards,  to  ter- 
minate at  the  junction  of  the  jugular  and  subclavian  vein  at  each 
side.  These  vessels  he  considers  the  "  absorbent  ducts  of  the 
glands ;  '  thymic  duds ;'  they  are  the  carriers  of  the  fluid  from  the 
thymus  into  the  veins." 

Sir  Astley  Cooper  concludes  his  anatomical  description  of  this 
gland  with  the  following  interesting  physiological  observations: 

"  As  the  thymus  secretes  all  the  parts  of  the  blood,  viz.  albumen, 
fibrine,  and  particles,  is  it  not  probable  that  the  gland  is  designed 
to  prepare  a  fluid  well  fitted  for  the  foetal  growth  and  nourishment 
from  the  blood  of  the  mother,  before  the  birth  of  the  foetus,  and, 
consequently,  before  chyle  is  formed  from  food? — and  this  process 
continues  for  a  short  time  after  birth,  the  quantity  of  fluid  secreted 
from  the  thymus  gradually  declining  as  that  of  cBylification  be- 
comes perfectly  established." 

FCETAL    LUNGS. 

The  Lungs  previously  to  the  act  of  inspiration,  are  dense  and 
solid  in  structure,  and  of  a  deep  red  colour ;  their  specific  gravity 
greater  than  water,  in  which  they  sink  to  the  bottom,  whereas  lung 
which  has  respired  will  float  upon  that  fluid.  The  specific  gravity 
is,  however,  no  test  of  the  real  weight  of  the  lung;  the  respired 
lung  being  actually  heavier  than  the  foetal.  Thus  the  weight  of  the 
foetal  lung,  at  about  the  middle  period  of  uterine  life,  is  to  the  w'eight 
of  the  body  as  1  to  60.*  But,  after  respiration,  the  relative  weight 
of  the  lung  to  the  entire  body  as  1  to  30. 

FCETAL    HEART. 

The  Heart  of  the  foetus  is  large  in  proportion  to  the  size  of  the 
body;  it  is  also  developed  very  early,  representing  at  first  a  simple 
vessel,  and  undergoing  various  degrees  of  complication  until  it 
arrives  at  the  compound  character  which  it  presents  after  birth.  The 
two  ventricles  form,  at  one  period,  a  single  cavity,  which  is  after- 
wards divided  into  two  by  the  septum  ventriculorum.     The  two 

*  Cruveilhier,  Anatomic  Descriptive,  vol.  ii.  p.  621. 


588  VISCERA  OF  THE  ABDOMEN.  * 

auricles  communicate  up  to  the  moment  of  birth,  the  septum  being 
incomplete,  and  leaving  a  large  opening  between  them,  ibe  foramen 
ovale  (foramen  of  Dotal.)* 

The  Ductus  arteriosus  is  another  peculiarity  of  the  foetus  con- 
nected with  the  heart;  it  is  a  communication  between  the  pulmo- 
nary artery  and  the  aorta.  It  degenerates  into  a  fibrous  cord  after 
birth,  from  the  double  cause  of  a  diversion  in  the  current  of  the 
blood  towards  the  lungs,  and  from  the  pressure  of  the  left  bronchus, 
caused  by  its  distension  with  air. 

VISCERA   OF    THE    ABDOMEN. 

At  an  early  period  of  uterine  life,  and  sometimes  at  the  period  of 
birth,  as  I  have  twice  observed,  in  the  imperfectly  developed  foetus 
tv/o  minute  fibrous  threads  may  be  seen,  passing  from  the  umbilicus 
to  the  mesentery.  These  are  the  remains  of  the  omphalo-mesen- 
teric  vessels. 

The  Omp/mJo-mesenteric  are  the  first  developed  vessels  of  the 
germ:  they  ramify  upon  the  vesicula  umbilicalis,  or  yolk-bag,  and 
supply  the  newly  formed  alimentary  canal  of  the  embryo.  From 
them,  as  from  a  centre,  the  general  circulating  system  is  produced. 
After  the  establishment  of  the  placental  circulation  they  cease  to 
carry  blood,  and  dwindle  to  the  size  of  mere  threads,  which  may  be 
easily  demonstrated  in  the  early  periods  of  uterine  life  ;  but  are 
completely  removed,  except  under  peculiar  circumstances,  at  a  later 
period.      % 

The  Stomach  is  of  small  size,  and  the  great  extremity  but  little 
developed.  It  is  also  more  vertical  in  direction  the  earlier  it  may 
be  examined,  a  position  that  would  seem  due  to  the  enormous  mag- 
nitude of  the  liver,  and  particularly  of  its  left  lobe. 

The  JJppendix  vermiformis  cceci  is  long  and  of  large  size,  and  is 
continued  directly  from  the  central  part  of  the  cul-de-sac  of  the 
caecum,  of  which  it  appears  to  be  a  constricted  continuation.  This 
is  the  character  of  the  appendix  casci  in  the  higher  quadrumana. 

The  large  intestines  are  filled  with  a  dark  green  viscous  secre- 
tion called  meconium  ((xtjxwv,  poppy),  from  its  resemblance  to  the  in- 
spissated juice  of  the  poppy. 

The  Pancreas  is  comparatively  larger  in  the  foetus  than  in  the 
adult. 

The  Spleen  is  comparatively  smaller  in  the  foetus  than  in  the 
adult. 

FmTAL    LIVER. 

The  Liver  is  the  first  formed  organ  in  the  embryo.  It  is  deve- 
loped from  the  alimentary  canal,  and,  at  about  the  third  week,  fills 
the  whole  abdomen,  and  is  one  half  the  weight  of  the  entire  embryo. 

*  Leonard  Botal,  of  Piedmont,  was  the  first  of  the  moderns  who  gave  an  account  of 
this  opening-,  in  a  work  published  in  1565.  His  description  is  very  imperlect.  The 
foramen  was  well  known  to  Galen. 


FCETAL  LIVER  AND  KIDNEYS.  589 

At  the  fourth  month  the  Uver  is  of  immense  size  in  proportion  to  the 
bulk  of  the  foetus.  Ai  bh'th  it  is  of  very  large  size  and  occupies  the 
whole  upper  part  of  the  abdomen.  The  left  lobe  is  as  large  as  the 
right,  and  the  falciform  ligament  corresponds  with  the  middle  line 
of  the  body.  The  liver  diminishes  rapidly  after  birth,  probably  from 
the  obliteration  of  the  umbilical  vein, 

KIDNEYS    AND    SUPRA-RENAL    CAPSULES. 

The  Kidneys  present  a  lobulated  appearance  in  the  foetus,  which 
is  the  permanent  type  amongst  some  animals,  as  in  the  bear,  the 
otter,  and  cetacea. 

The  Supra-renal  capsules  are  organs  which  appear,  from  their 
early  and  considerable  developement,  to  belong  especially  to  the 
economy  of  the  foetus.  They  are  distinctly  formed  at  the  second 
month  of  embryonic  life,  and  are  greater  in  size  and  weight  than 
the  kidneys.  At  the  fourth  month  they  are  equalled  in  bulk  by  the 
kidneys,  and  at  birth  they  are  about  one-third  less  than  those 
organs. 

VISCERA    OF    THE    PELVIS. 

The  Bladder  in  the  foetus  is  long  and  conical,  and  is  situated  al- 
together above  the  upper  border  of  the  os  pubis,  which  is  as  yet 
small  and  undeveloped.  It  is,  indeed,  an  abdominal  viscus,  and  is 
connected  superiorly  with  a  fibrous  cord,  called  the  uraclius,  of 
which  it  appears  to  be  an  expansion. 

The  Uraclius  is  continued  upwards  to  the  umbilicus,  and  becomes 
connected  with  the  umbilical  cord.  In  animals  it  is  a  pervious  duct, 
and  is  continuous  with  one  of  the  membranes  of  the  embryo — the 
allantois.  It  has  been  found  pervious  in  the  human  foetus,  and  the 
urine  has  been  passed  through  the  umbilicus.  Calculous  concretions 
have  also  been  found  in  its  coui'se. 

The  Uterus,  in  the  early  periods  of  embryonic  existence,  appears 
to  be  bifid,  from  the  large  size  of  the  Fallopian  tubes,  and  the  small 
developement  of  the  body  of  the  organ.  At  the  end  of  the  fourth 
month  the  body  assumes  a  larger  bulk,  and  the  bifid  appearance  is 
lost.  The  cervix  uteri  in  the  foetus  is  larger  than  the  body  of  the 
organ. 

The  Ovaries  are  situated,  like  the  testicles,  in  the  lumbar  region, 
near  to  the  kidneys,  and  descend  from  thence  gradually  into  the 
pelvis. 

TESTES. 

The  Testicles  in  the  embryo  are  situated  in  the  lumbar  regions, 
immediately  in  front  of  and  somewhat  below  the  kidneys.  They 
have  connected  with  them  inferiorly  a  peculiar  structure  which 
assists  in  their  descent,  and  is  called  the  gubernaculum  testis. 

The  Gubernaculum  is  a  soft  and  conical  cord  composed  of  cellular 
tissue  containing  in  its  cells  a  gelatiniform  fluid.  In  the  abdomen  it 
lies  in  front  of  the  psoas  muscle,  and  passes  along  tlie  spermatic 

50 


590  TESTES. 

canal  which  it  serves  to  distend  for  the  passage  of  the  testis.  It  is 
attached  by  its  superior  and  larger  extremity  to  the  lower  end  of 
the  testis  and  epididymis,  and  by  the  inferior  extremity  to  the  bottom 
of  the  scrotum.  The  gubernaculum  is  surrounded  by  a  thin  layer 
of  muscular  fibres,  the  cremaster,  which  pass  upwards' upon  this 
body  to  be  attached  to  the  testis.  Inferiorly  the  muscular  fibres 
divide  into  three  processes  which,  according  to  Mr.  Curling,*  are 
thus  attached: — *' The  external  and  broadest  is  connected  to  Pou- 
part's  ligament  in  the  inguinal  canal ;  the  middle  forms  a  lengthened 
band,  which  escapes  at  the  external  abdominal  ring,  and  descends 
to  the  bottom  of  the  scrotum,  where  it  joins  the  dartos  ;  the  internal 
passes  in  the  direction  inwards,  and  has  a  firm  attachment  to  the 
OS  pubis  and  sheath  of  the  rectus  muscle.  Besides  these  a  number 
of  muscular  fibres  are  reflected  from  the  internal  oblique  on  the 
front  of  the  o-ubernaculum." 


Fig-.  204. 


Fi^.  205. 


The  Descent  of  the  testicle  is  very  gradual  and  progressive. 
Between  the  fifth  and  sixth  month  it  has  reached  the  lower  part  of 
the  psoas  muscle,  and  during  the  seventh  it  makes  its  way  through 
the  spermatic  canal,  and  descends  into  the  scrotum. 

While  situated  in  the  lumbar  region,  the  testis  and  gubernaculum 
are  placed  behind  the  peritoneum,  by  which  they  are  invested  upon 
their  anterior  surface  and  sides.  As  they  descend,  the  investing 
peritoneum  is  carried  downwards  with  the  testis  into  the  scrotum, 
forming  a  lengthened  pouch  which  by  its  upper  extremity  opens 

Fi{r.  204.  A  diagram  illustrating-  the  descent  of  the  testis.  1.  The  testis.  2.  The 
epididymis.  3,  3.  The  peritoneum.  4.  The  pouch  formed  around  the  testis  by  tiie 
peritoneum.  5.  The  puliic  portion  of  the  cremaster  attached  to  the  lower  part  of  the 
testis.  6.  The  portion  of  tiic  cremaster  attached  to  Poupart's  ligament.  Tlie  mode  of 
eversion  of  the  cremaster  is  sliown  by  these  lines.  7.  The  gubernaculum,  attached  to 
the  bottom  of  the  scrotum,  and  b(;cf)ming  shortened  by  the  contraction  of  the  tnuscular 
fibres  wiiich  surround  it.     8,  8.  The  cavity  of  the  scrotum.     9.  The  peritoneal  cavity. 

Fig.  205.  In  this  figure  the  testis  has  completed  its  descent.  The  gubernaculum  is 
shortened  to  its  utmost,  and  (he  cremaster  is  completely  everted.  The  pouch  of  peri- 
toneum above  the  testis  is  com|)resHed  so  as  to  form  a  tubular  canal.  I.  A  dotted  line 
marks  the  point  at  which  the  timica  vaginalis  will  terminate  superiorly;  and  liie  figure 
2  its  cavity.     3.  The  peritoneal  cavity. 

*  See  an  excellent  paper  "On  the  Structure  of  the  Gubernaculum,"  &.e.  by  Mr.  Cur- 
ling, Lecturer  on  Morbid  Anatomy  in  the  London  Hospital,  in  the  Lancet,  vol.  ii. 
1840-41,  p.  70. 


DESCENT  OF  THE  TESTICLE.  591 

into  the  cavity  of  the  peritoneum.  The  upper  part  of  this  pouch 
being  compressed  by  the  spermatic  canal  is  gradually  obUterated, 
the  obliteration  extending  downwards  along  the  spermatic  cord 
nearly  to  the  testis.  That  portion  of  the  peritoneum  which  imme- 
diately surrounds  the  testis  is,  by  the  above  process,  cut  off  from  its 
continuity  with  the  peritoneum,  and  is  termed  the  tunica  vaginalis; 
and  as  this  membrane  must  be  obviously  a  shut  sac,  one  portion  of 
it  investing  the  testis,  and  the  other  being  reflected  so  as  to  form  a 
loose  bag  around  it,  its  two  portions  have  received  the  appellations 
of  tunica  vaginalis  propria,  and  tunica  vaginalis  reflexa. 

The  descent  of  the  testis  is  effected  by  means  of  the  traction  of  the 
muscle  of  the  gubernaculum  (cremaster).  "  The  fibres,"  writes  Mr. 
Curling,*  "  proceeding  from  Poupart's  ligament  and  the  obliquus 
internus,  tend  to  guide  the  gland  into  the  inguinal  canal;  those 
attached  to  the  os  pubis,  to  draw  it  below  the  abdominal  ring;  and 
the  process  descending  to  the  scrotum,  to  direct  it  to  its  final  des- 
tination." During  the  descent  "  the  muscle  of  the  testis  is  gra- 
dually everted,  until,  when  the  transition  is  completed,  it  forms  a 
muscular  envelope  external  to  the  process  .of  peritoneum,  which 
surrounds  the  gland  and  the  front  of  the  cord."  "  The  mass  com- 
posing the  central  part  of  the  gubernaculum,  which  is  so  soft,  lax, 
and  yielding  as  in  every  way  to  facilitate  these  changes,  becomes 
gradually  diffused,  and,  after  the  arrival  of  the  testicle  in  the 
scrotum,  contributes  to  form  the  loose  cellular  tissue  which  after- 
wards exists  so  abundantly  in  this  part."  The  attachment  of  the 
gubernaculum  to  the  bottom  of  the  scrotum  is  indicated  throughout 
life  by  distinct  traces. 

*  Loc.  cit. 


I  ]\'  D  E  X . 


Abdomen,  518. 
Abdominal  regions,  518. 
Abdominal  ring,  211,  273. 
Abductor  oculi,  172. 
Acetabulum,  108. 
Acini,  544. 
Adductor  oculi,  172. 
Air-cells,  516. 
Albino,  475. 

Alcock,  Dr.,  researches  of,  424. 
Alimentary  canal,  523. 
Allantois,  589. 
Amphi-arthrosis,  122. 
Ampulla,  486. 
Amygdalos,  525. 
Andersch,  notice  of,  420. 
Annulus  ovalis,  500. 
Antihelix,  479. 
Antitragus,  479. 
Antrum  of  Highmore,  66. 

pylori,  528. 
Anus,  532,  538. 
Aorta,  abdominal,  290. 

arch,  289. 

ascending,  288. 

thoracic,  290. 
Aortic  sinuses,  287. 
Aponeurosis,  162. 
Apophysis,  41. 

Apparatus  ligamentosus  colli,  130. 
Appendices  epiploicoe,  522. 
Appendix  vermiformis,  530,  559. 
Aqua  labyrintlii,  488. 
Aqueductus  cochlece,  488. 
vestibuli,  486. 
Aqueduct  of  Sylvius,  398. 
Aqueous  humour,  473. 
Arachnoid  membrane,  390,  408. 
Arantius,  notice  of,  503. 
Arbor  vitoe,  401. 

ulerina,  574. 
Arch,  femoral,  282. 

palmar,  superficial,  322. 
Arciform  fibres,  406. 
Areola,  579. 
Arnold,  Frederick,  researches,  457. 


Arteries. 


50* 


General  anatomy,  285. 
structure,  2y6. 
anastomotica  femor,  342. 

magna,  317. 
aorta,  2«7. 

articulares  genCi,  343. 
auricula  anterior,  299. 
posterior,  298. 
axillary,  313. 
basilar,  308. 
brachial,  31  6. 
bronchial,  322. 
bulbosi,  335. 
calcanean,  348. 
carotid  common,  292. 
external,  293. 
internal,  302.    • 
carpal  ulnar,  321. 
radi;il,  319. 
cavernosi,  335. 
centralis  retinas,  305,  474. 
cerebellar  inferior,  309. 
superior,  309. 
cerebral,  305. 
cervicalis  anterior,  311. 
posterior,  311. 
choroidean,  306. 
ciliary,  305. 

circumflex  anterior,  315. 
external,  341. 
circumflex  ilii,  337,  340. 
internal,  341. 
posterior,  315. 
coccygeal,  333. 
cceliac,  323. 
colic,  328. 

comes  nervi  ischiat.,  334. 
comes  pbrenici,  312. 
communicans  cerebri,  306. 

pedis,  347. 
coronaria  dextra,  291. 
labii,  297. 
sinistra,  291. 
venlriculi,  323. 
corporis  bulbosi,  335. 

cavernosi,  335. 
cremasteric,  337. 


594 


INDEX. 


Arteries — continued. 
cysiic,  325. 
dental,  302. 
digitales  manfts,  322, 

fjedis,  349. 
dorsales  pollicis,  319. 
dorsalis  lingutE,  296. 
carpi,  319. 
hallucis,  345. 
nasi,  305. 
pedis,  345. 
penis,  335. 
scapulse,  310. 
emulg-ent,  330. 
epigastric,  337. 

superficial,  340. 
ethmoidal,  305, 
facial,  296. 
femoral,  338. 
frontal,  305. 
gastric,  323. 
gastro-duodenalis,  325. 
epiploica  dextra,  325. 
sinistra,  326. 
gluteal,  336. 

inferior,  334. 
haemorrhoidal  ext.,  333. 

middle,  332. 
superior,  330. 
inferior,  334. 
hepatic,  324. 
ileo-colic,  328. 
iliac,  common,  331 
external,  337. 
internal,  331, 
ilio-lumbar,  335. 
infra-orbital,  302. 
jnnominata,  291. 
intercostal,  322. 

anterior,  312, 
superior,  312. 
inter-osseous,  321. 
intestini  tenuis,  328. 
ischiatic,  333. 
labial,  297. 
lachrymal,  304. 
laryngeal,  294, 
lateralis  nasi,  297, 
lingual,  2;)5. 
lumbar,  330. 
malleolar,  344. 
mammary  internal,  312. 
masseteric,  297, 
mastoid,  297. 
maxillary  internal,  299. 
mediastinal,  312. 
meningea  anterior,  304, 
inferior,  298, 
media,  301, 
parva,  301. 
posterior,  309. 
mesenteric,  326. 

inferior,  329. 
metacarpal,  319. 


Arteries — continued. 

metatiirsal,  345. 
musculii-phrenic,  312. 
nasal,  305. 
obturator,  335.    . 
occipital,  297, 
oesophageal,  322. 
ophthalmic,  304. 
orbilar,  299. 
palatine  inferior,  297, 

posterior,  302, 
palpebral,  305, 
pancrealica  magna,  326. 
pancrealicae  paivee,  325. 
pancreatico-daoden.,  325. 
parotidean,  298. 
perforanles,  femoral,  341, 
palmares,  320, 
plantares,  349, 
pericardiac,  312. 
perineal  superficial,  334. 
peroneal,  347. 
pharyngea  ascendens,  298. 
phrenic,  323. 
plantar  external,  349. 
internal,  348. 
popliteal,  342. 
princeps  cervicis,  298. 

pollicis,  319. 
profunda  cervicis,  311. 

femoris,  340. 

inferior,  317. 

superior,  317. 
pterygoid,  297. 
pterygopalatine,  302. 
pudic  external,  340. 
pudic  internal,  334, 
pulmonary,  350,  503. 
pyloric,  3^5. 
radial,  318. 
radialis  indicis,  319. 
ranine,  295. 
recurrens  inteross,,  321. 

radialis,  318. 
tibialis,  344. 
ulnaris,  321. 
renal,  330. 
sacra  media,  330. 

lateralis,  336. 
scapular  posterior,  310. 
sigmoid,  330. 
spermatic,  328. 
spheno-palatine,  302. 
spinal,  309. 
splenic,  325. 
Btylo-mastoid,  298. 
subclavian,  3U6. 
sublingual,  2ii6. 
submaxillary,  297. 
submental,  297. 
subscapular,  314. 
supcrficialis  cervicis,  311. 

volte,  318. 
supra-orbital,  3U4. 


INDEX. 


595 


Arteries — continued. 

supra-renal,  330. 

scapular,  310. 
sural,  343. 
tarsea,  345. 
temporal,  299. 
temporales  profundae,  299. 
thoracic,  314. 
thyroidea  inferior,  310, 
superior,  294. 
tibialis  antica,  343. 

postica,  347. 
transversalis  colli,  310, 
faciei,  298. 
humeri,  310. 
perinei,  334. 
tympanic,  301. 
uln.r,  320. 
umbilical,  332. 
uterine,  335, 
vaginal,  335, 
vasa  brevia,  326. 

intestini  tenuis,  328. 
vertebral,  308. 
vesical,  332. 
Vidian,  302. 
Arthrodia,  123, 
Articulations,  126. 
Arytenoid  cartilages,  508. 
Arytenoid  glands^  512. 
Auricles  of  the  heart,  499. 
Auriculo-ventricular  openings,  500,  501. 


B. 


Barry,  Dr.,  researches  of,  577. 
Base  of  the  brain,  401. 
Bauhini,  valvula,  533. 
Bell,  Sir  C,  researches  of,  385, 
Berzelius,  analysis  of  bone,  337. 
Biliary  ducts,  551. 
Bladder,  557. 

Bones,  chemical  composition,  37. 
developement,  41. 
general  anatomy,  37. 
structure,  38. 
astragalus,  115. 
atlas,  44. 
axis,  45. 
calcis,  116. 
carpus,  1 00. 
clavicula,  94, 
coccyx,  50. 
costse,  92. 
cuboides,  118. 
cuneiforme  carpi,  101. 

externum  tarsi,  117. 
internum,  117. 
medium,  117. 
ethmoides,  64. 
femur,  1 10. 
fibula,  114. 
frontule,  54. 


Bones — continued. 

humerus,  96. 

hyoides,  91, 

ilium,  106. 

inuominatum,  106. 

ischium,  107. 

lachrymale,  68. 

magnum,  103. 

malare,  68. 

maxilhire  superius,  65. 

maxillare  inferius,  71. 

metacarpus,  104. 

metatarsus,  118. 

nasi,  65. 

naviculare,  116. 

occipilale,  50. 

palati,  69, 

parietale,  53, 

patella,  1 1.3. 

phalanges  manus,  105. 
pedis,  120. 

pisi  forme,  102. 

pubis,  108, 

radius,  99, 

sacrum,  49. 

scaphoides  carpi,  100, 
tarsi,  115. 

scapula,  95. 

semilunare,  101. 

sesamoidea  manus,  120. 
pedis,  120. 

sphenoides,  60, 

sternum,  92. 

tarsus,  115. 

temporal,  56, 

tibia,  113. 

trapezoides,  102. 

trapezium,  102. 

triquetra,  74. 

turbinatum  inferius,  71. 
superius,  64, 

ulna,  98. 

unciforme,  103. 

ungui-;,  68. 

vertebra  prominens,  46. 

vertebrae  cervical,  44. 
dorsal,  46. 
lumbar,  47. 

vomer,  71. 

Wormiana,  74. 
Botal,  foramen  of,  588. 

notice  of,  588. 
Bowman,  Mr.  researches  of,  164. 
Brain,  387. 
Bronchi,  513. 
Bronchial  cells,  516, 
tubes,  516, 
Bronchocele,  514. 
Brunn,  Voii,  notice  of,  536. 
Brunner's  glands,  536. 
Bulb,  corpus  spongiosum,  563. 
Bulbous  part  o'  tiie  urethra,  566. 
Bulbus  olfactorius,  412. 


596 


Eursse  rmicosap,  125. 


Cfecum,  530. 

Calamus  scriptorius,  399. 

Calyces,  556. 

Camper's  lio-ament,  278. 

Canal  of  Fontana,  470. 

Petit,  474. 

Sylvius,  398. 
Canals  of  Havers,  38. 
Canthi,  475. 
Capillaries,  286. 
Capitula  laryngis,  508. 
Capsule  of  Glisson,  .545. 
Capsules  supra-renal,  553. 
Caput  gallinaginis,  564. 
Cardia,  628. 
Carpus,  100. 
Cartilage,  124. 
Cartilages. 

inter-articular  of  the  clavicle,  141, 

inter-articular  of  the  jaw,  133. 

inter. articular  of  the  wrist,  146. 

semilunar,  154. 
Cartilaginification,  41. 
Caruncula  lachrymalis,  477. 
CarunculEB  myrtiformes,  579. 
Casserian  ganglion,  425. 
Cauda  equina,  430. 
Cementum,  86. 
Centrum  ovale  majus,  392. 
minus,  392. 
Cerebellinn,  400. 
Cercbro-spinal  axis,  382. 
Cerebrum,  .391. 
Cernminous  follicle?,  480. 
Cervical  ganglia,  458. 
Chambers  of  the  eye,  473. 
Checks,  524. 

ChordcE  tendincae,  501,  504. 
vocalcs,  509. 
Willisii,  388. 
Choroid  membrane,  464. 

ple.xus,  394,  397,  399. 
Cilia,  476. 
Ciliary  canal,  470. 

lig.iment,  470. 
processes,  471. 
Circle  of  Willis,  310. 
Circulation,  adult,  499. 
foetal,  553. 
Clitoris,  578. 
Cochlea,  487. 

Cock,  Mr.,  researches  of,  423. 
Coeliac  axis,  323. 
Colon,  530. 
Columna  na.si,  465. 
Columna;  eiirncfi;,  502,  504. 

pa  pi  1  hi  res,  502. 
Commissures,  398,  407. 
great,  392. 


Conarium,  3D8. 
Concha,  479. 

Congestion  of  the  liver,  550. 
Coni  renales,  555. 

vasculosi,  571. 
Conjunctiva,  477. 

Cooper,  Sir  Astley,  researches  of,  585. 
Corium,  41)2. 
Cornea,  468. 
Cornicula  laryngis,  508. 
Cornu  Ammonis,  395. 
Cornua  of  the  ventricles,  392. 
Corona  glandis,  562. 
Coronary  Viilve,  500. 
Corpora  albicantia,  402. 
Araiitii,  504. 
cavernosa,  563. 
Malpighiana,  555. 
olivaria,  406. 
pisiformia,  402. 
pyramidalia,  403. 
quadrigemina,  398. 
reslilbrmia,  401,  404. 
striata,  394. 
Corpus  callosum,  392,  407. 
cavernosum,  563, 
fimbriatum,  394. 
genticulatum  externum,  398. 
internum,  398. 
Highmorianum,  569. 
lutcuin,  577. 
rhomboideum,  401. 
spongiosum,  563. 
stiiatum,  394. 
Co.stal  cartilages,  94. 
Cotunnius,  notice  of,  487. 
Cowper's  glands,  566. 
Cranial  nerves,  411. 
Cribriform  fascia,  281. 
Cricoid  cartilige,  503. 
Crico-thyroid  membrane,  509. 
Crura  cerebelli,  401. 
cerebri,  403. 
penis,  563. 
Crural  canal,  339. 

ring,  282. 
Crystalline  lens,  473. 
Cuneiform  cartilages,  509. 
Cupola,  487. 

Curling,  Mr.  researches  of,  590. 
Cuticle,  'J  94. 
Cutis,  492. 
Cystic  duct,  551. 

D. 

Dartos,  567. 

Davy,  Dr.,  researches  of,  308. 

Derbyshire  neck,  514. 

Dermis,  4i)2. 

Detrusor  urina?,  559. 

Deutch,  reson relics  of,  39. 

Diaphragm,  215. 


597 


Diaphysis,  41. 
Diarthrosis,  123. 
Digital  cavity,  395. 
Diverg-ing  fibres,  405. 
Dorsi-spinal  veins,  368. 
Ductus  ad  nasum,  478. 

arteriosus,  588. 

comm.  choledochus,  551. 

cysticus,  551. 

ejaculatorius,  564, 

hepaticuB,  551. 

lymphaticus  dexter,  381. 

pancreaticus,  552. 

prostaticus,  560. 

thoracicus,  37D. 

venosus,  581. 
Duodenum,  528. 
Dura  mater,  387,  408. 

E. 

Ear,  478. 

Ejaculatory  duct,  564. 
Elastic  tissue,  125. 
Enamel,  85. 
Enarthrosis,  123. 
Encephalon,  387. 
Endolymph,  490. 
Ensiforrn  cartilage,  92. 
Epidermis,  494. 
Epididymis,  540. 
Epigastric  region,  518. 
Epiglottic  gland,  512. 
Epiglottis,  509.     « 
Epiglotto-hyoidean  ligament,  509. 
Epiphysis,  41. 
Epitrielium,  533. 
Erectile  tissue,  563. 
Eustachian  tube,  483. 
valve,  500. 
Eustachius,  notice  of,  500. 
Eye,  467. 

brows,  475. 

globe,  467. 

lashes,  476. 

lids,  475, 


Falciform  process,  280. 
Fallopian  tubes,  576. 
Fallopius,  notice  of,  547. 
Falx  cerebelli,  389. 

cerebri,  3S9. 
Fascia. 

general  anatomy  of,  270. 

cervical,  deep,  271. 

superficial,  271. 

cribriform,  281. 

dentata,  396. 

iliaca,  275. 

inter-columnar,  211. 

lata,  280. 

lumbar,  213. 


Fascia — covtimied. 

obturator,  277. 
palmar,  279. 
pelvica,  276. 
perineal,  277. 
plantar,  283. 
propria,  282. 
recto-vesical,  277. 
spermatica,  211. 
temporal,  271. 
thoracic,  272. 
transversalis,  273. 
Fauces,  525. 
Femoral  arch,  2S2. 
canal,  339. 
hernia,  282. 
ring,  282. 
Fenestra  ovalis,  483. 

rotunda,  483. 
Fibres  of  the  heart,  504,  506. 
Fibro-cartilage,  124. 

inter-articular  of  the  clavicle,  141. 
jaw,  133. 
knee,  154. 
wrist,  146. 
Fimbriae,  Fallopian,  576. 
Fissure  of  Bichat,  392. 
Sylvius,  402. 
Fissures  of  the  liver,  540. 
Flocculus,  400. 
Fcetal  circulation,  582. 
Foetus,  anatomy  of,  581. 
Follicles  of  Lieberkuhn,  536. 
Fontana,  notice  of,  470. 
Foramen  coscum,  491. 

commune  anterius,  398. 
posterius,  398. 
Munro,  of,  396. 
ovale,  581. 
saphenum,  280. 
Soemmering,  of,  472. 
Winsiow,  of,  521, 
Foramina  Tliebesii,  500. 
Fornix,  394. 
Fossa  innoniinata,  479. 

navicularis  urethrre,  566. 
pudendi,  579. 
ovalis,  500. 
scaphoides,  479. 
Fourchette,  579. 
Frcena  epiglotlidis,  509. 
Frmnum  labii,  579. 

lingute,  491. 
prepulii,  562, 


Galea  capitis,  168. 
Galen,  285. 
Gall-bladder,  551. 
Ganglia,  cervical,  458. 

increase  of,  406. 

lumbar,  463. 

sacral,  463. 


598 


Ganglia  semilunar,  462. 
structure  of,  387. 
tlioracic,  461. 
Ganglion  of  Anderscii,  420. 
Arnnld's.  457. 
azjgos,  463. 
cardiac,  461. 
carotid,  458. 
Casscrian,  425. 
ciliary,  455. 
Cloquet's,  455. 
impar,  463. 
jugfular,  420. 
lenticular,  455. 
Meckel's,  455. 
naso-palatine,  455. 
otic,  457. 
petrous,  420. 
plcxiforme,  421. 
Ribes,  of,  455. 
sphenopalatine,  455. 
submaxillary,  457. 
thyroid,  460. 
vertebral,  460. 
Gimbernat's  lig-ament,  211. 
Ginglymup,  123. 
Gland,  epiglottic,  512. 
lachryin.il,  477. 
parotid,  525. 
pineal,  3U8. 
pituitary,  402. 
prostate,  560. 
thymus,  585. 
thyroid,  51.3. 
Glands,  aggregate,  536. 
ai'ytcnoid,  512. 
Brunner's,  536. 
Cowper's,  566. 
duodenal,  536. 
gastric,  535. 
ingumal,  375. 
Lieberkuhn's,  536. 
lymphatic,  371. 
mammary,  579. 
mesenteric,  378. 
Meibomian,  476. 
oesopbigoal,  535. 
Pacchionian,  388. 
Peyer'B,  536. 
pharyngeal,  535. 
salivary,  .'")25. 
solitary,  536. 
sublingual,  526. 
submaxillary,  52G. 
tracheal,  513. 
Glandulaj  odorifer.r,  562. 
Pacchioni,  388. 
'J'ysoni,  562. 
Glans  clitoridis,  549. 

penis,  534. 
Glisson,  notice  of,  521. 
CJIisson's  capsule,  545. 
Globus  in^ijnr  epididymis,  5G8. 
minor  epididymis,  568. 


Glomeruli,  557. 

Glottis,  511. 

Goodsir,  !\lr.,  researches  of,  86. 

Goitre,  514. 

Gomphosis,  122. 

Graafian  vesicles,  548. 

Grainger,  Mr.,  researches  of,  385. 

Gubernaculum  testis,  591. _ 

Gums,  524. 

Guthrie,  Mr.,  researches  of,  559. 

Guthrie's  muscle,  220. 

H. 

Hair,  496. 

Hall,  Dr.  Marshall,  researches  of,  385. 

Harmonia,  122. 

Haversian  canals,  338. 

Heart,  497. 

Helicine  arteries,  564. 

Helicotrema,  488. 

Helix,  479. 

Hepatic  duct,  546. 

Hernia,  congenital,  274. 

diaphragmatic,  216. 

direct,  274. 

encysted,  274. 

femoral,  282. 

inguinal,  274. 
Highmore,  notice  of,  569. 
Hilton's  muscle,  511. 
Hilus  lienis,  552. 

renalis,  555. 
Hippocampus  major,  395. 
minor,  395. 
Horner's  muscle,  170. 
Houston,  Mr.,  researches  of,  533.* 
Humours  of  the  eye,  473. 
Hyaloid  membrane,  473. 
Hymen,  578. 

Hypochondriac  regions,  518. 
Hypogastric  region,  518. 


Ileo-cffical  valve,  533. 
Ileum,  530. 
Iliac  regions,  518. 
Incus,  481. 
Infundibula,  556. 
Infundibulum,  402. 
Inguinal  r(-gion,518. 
Intur-arlicular  cartilages  of  the  clavicle, 
141. 
jaw,  133. 
wrist,  146. 
Inter-columnar  fibres,  211. 
Intcr-vcrtebral  sub>tancc,  125. 
Intestinal  canal,  530. 
Iris,  47(1. 

Isthmus  of  the  fauces,  525. 
Iter  ad  iridmdihuliim,  398. 

a  tertio  ad  (juarluai  ventriculum,398. 


599 


Jacob's  membrane,  471. 
Jejunum,  530. 
Joint,  ankle,  157. 

elbow,  143. 

hip,  150. 

lower  jaw,  132. 

knee,  151. 

shoulder,  142. 

wrist,  146. 
Jones,  Mr.,  researches  of,  488. 

K. 

Kidneys,  ,526. 

Kiernan,  Mr,  researches  of  516. 
King,  Mr.  T.  W.,  researches  of,  501. 
Krause,  researches  of,  222. 


Labia  majora,  549. 
minora,  549. 
Labyrinth,  485. 
Lachrymal  canals,  478. 
gland,  477. 
papillas,  475. 
punctn,  475. 
sac,  478. 
tubercles,  475. 
Lacteals,  379. 
LacuuEE,  539. 
Lacus  lachrymalis,  475. 
Lamina  cribrosa,  468. 
spiralis,  487. 
Laryngotomy,  509. 
Larynx,  508. 
Lateral  ventricles,  392. 
Lauth,  researches  of,  569. 
Lens,  474. 

Lenticular  ganglion,  455. 
Lieberkuhn's  follicles,  536, 
Lien  succcnturiatus,  553. 
Ligament,  125. 
Ligaments,  122. 

acromio-clavicular,  141. 
alar,  155. 
ankle,  of  the,  157. 
annular,  of  the  ankle,  283. 
radius,  145. 
wrist,  anterior,  147. 
posterior,  279. 
arcuatum  externum,  215. 
internum,  215. 
atlo-axoid,  131. 
breve  plantte,  159. 
calcaneo-astragaloid,  160. 
cuboid,  159. 
scaphoid,  159. 
capsular  of  the  hip,  150. 
jaw,  132. 
rib,  134. 
shoulder,  142. 


Ligaments — continued. 

capsular  of  the  thumb,  149. 
carpal,  147. 
carpo-metacarpal,  148. 
common  anterior,  \26- 
posterior,  127. 
conoid,  141. 
coracoid,  142. 
coraco-acromial,  142. 
clavicular,  141, 
humeral,  142. 
coronary,  145. 

of  the  knee,  154. 
costo-clavicular,  140. 
sternal,  135. 
transverse,  134,  135. 
vertebral,  134. 
xyphoid,  136. 
cotyloid,  151. 
crico-thyroidean,  502. 
crucial,  153. 
cruciform,  131. 
deltoid,  158. 
elbow,  of  the,  143. 
epiglotto  hyoidean,  509. 
glenoid,  142. 
hip-joint,  of  the,  150. 
ilio-femorul,  150. 
inter-articular  of  ribs,  134. 
inter-clavicular,  140. 
inter-osseous, 

calcaneo-astragal,  159. 
peroneotibial,  156. 
radio-ulnar,  145. 
inter-spinous,  128. 
inter-transverse,  128. 
inter-vertebral,  127. 
knee,  of  the,  151. 
lateral  of  the  ankle,  158. 
elbow,  143. 
jaw,  132. 
knee,  153. 

phalanges,  foot,  161. 
phalanges,  hand,  150. 
wrist,  147. 
liver,  of  the,  514. 
longum  plantoe,  159. 
himbo-iliac,  136. 
lumbo-sacral,  136. 
melacarpo-phalangeal,  149. 
metatarsal  plialangeal,  161. 
mucosum,  155. 
nuchte,  196. 
oblique,  145. 
obturator,  139. 
occipito-atloid,  129. 
axoid,  130. 
odontoid,  130. 
orbicular,  145. 
palpebral,  476. 
patella?,  152. 
peroneotibial,  156. 
phalanges  of  the  foot,  161. 
of  the  hand,  149. 


600 


Ligaments — continued. 

plantar,  long,  159. 
plantar,  short,  159. 
postlcum  Win^^lowii,  152. 
pteryg-o-rnaxiUary,  132. 
pubic,  139. 
radio-iilnar,  145. 
rhomboid,  140. 
rotundum,  hepalis,  540. 
sacrococcygeiin,  138. 
sacro-iliac,  137. 
sacro-ischiatic  anterior,  138. 
posterior,  138. 
stellate,  134. 
sterno-clavicLilar,  140. 
stylo-maxillary,  272. 
sub-flav;.,  127. 
subpubic,  139. 
supra-ppinous,  128. 
suspensorium  hepatis,  540. 

penis,  563. 
tarsal,  158. 
tarso-metatarsal,  160. 
teres,  151. 

thyroarytenoid,  509. 
thyro-hyoidean,  509, 
tibio-fibLilar,  156. 
transverse,  158. 

of  the  acetabulinTi,  151. 
of  the  ankle,  157. 
of  the  atlas,  131. 
of  the  knee,  153. 
of  the  metacarpus,  149. 
of  the  metatarsus,  158. 
of  the  scapula,  142. 
of  the  semilunar  cartilages,  153. 
trapezoid,  141. 
tympanum,  of  the,  481. 
wrist,  of  the,  14G. 
Zinn,  ot;  171. 
Ligamentum  nucliae,  196. 
Limbus  luteus,  472. 
Linea  alba,  210. 
Linece  seini-lunares,  210. 

transversos,  210,  399. 
Linguetta  laminosa,  401. 
Lips,  524. 

Liquor  Cotunnii,  488. 
Mori/agni,  474. 
Scarpa,  of,  490. 
Liver,  539. 

Lobules  of  the  liver,  544. 
Lobuli  testis,  5G8. 
Lobules  auris,  479. 

pncumogastricus,  400. 
Lobus  caudatus,  543. 
quadraiUH,  543. 
Spigelii,  544. 
Locus  niger,  403. 

perforatus,  403. 
Lower,  notice  of,  500. 
Lumbar  fasci.i,  213. 

regions,  518. 
Lungs,  514. 


Lunula,  495. 

Lymphatic  glands  and  vessels,  371. 

axillary',  374. 

bronchial,  377. 

caidiac,  378. 

cervical,  373. 

head  and  neck,  373. 

heart,  378. 

iliac,  377. 

inguinal,  375. 

intestines,  378. 

kidney,  379. 

lacteal^  379. 

liver,  378. 

lower  extremity,  375. 

lungs,  377. 

mediastinal,  376. 

mesenteric,  378. 

pelvic  viscera,  379. 

popliteal,  375. 

spleen,  378. 

stomach,  378. 

testicle,  379. 

trunk,  376. 

upper  extremity,  374. 

viscera,  377. 
Lyra,  396, 

M. 

Malleus,  481. 

Mammee,  579. 

Mammary  eland,  579. 

Mastoid  cells,  483. 

Matrix,  495. 

Maxillo  pharyngeal  space,  189. 

Mayo,  Mr  ,  le-earches  of,  415. 

Meatus  auditoriur^,  480. 

urinarius,  female,  579. 
male,  562. 
Meatuses  of  the  nans,  466. 
Meckel's  ganglion,  455. 
Meconium,  559. 
Mediasiinum,  517. 

testis,  569. 
Medulla  of  bones,  4i. 

oblongata,  403. 
Meibomian  glands,  476. 
Meibomius,  notice  of^  476. 
Membrana  dcntata,  408.        , 

nictitans,  477. 

pigment!,  470. 
Membrana  pupiilaris,  468.  , 

eacciformis,  146. 

tympani,  480. 
Membrane,  choroid,  469. 

hyaloid,  473. 

Jacob's,  471. 

of  the  ventricles,  400. 
Membranous  urethra,  565. 
Meniscus,  124. 
Mi^scntcric  glands,  379. 
Me-cntcry,  522. 
Mcso-colon,  522. 


601 


Meso-rectum,  522. 

Metacarpu.--,  104. 

Metatarsus,  118. 

Miescher^  researches  of,  39. 

Mitral  valves,  504. 

Modiolus,  487. 

Mons  Veneris,  578. 

Morgagni,  notice  of,  474. 

Morsiis  Diaboli,  576. 

Motor  tract,  414. 

Mouth,  523. 

Mucous  membrane,  structure,  533. 

Muller,  researches  of,  39. 

Muscles. 

general  anatomy  of,  162. 
developement  of,  164. 
structure,  163. 
abductor  min.  digiti,  242. 
abduc.  min.  dig.  pedis,  264. 
indicis,  243. 
pollicis,  240. 
pedis,  264. 
accelerator  urinee,  219. 
accessor! us,  266. 
adductor  brevis,  254. 
longus,  253. 
magnus,  254. 
min.  digiti,  242. 
pollicis,  241. 
pedis,  267. 
anconeus,  238. 
anti-tragicus,  480. 
arytenoideiis,  510. 
arytenoepigiot.  inf.,  511. 

superior,  511. 
attollens  anrcm,  179. 
oculum,  171. 
attrahens  aurem,  179.    • 
auricularus,  238. 
azygos  uvulae,  192. 
basioglossus,  187. 
biceps  flexor  cruris,  255. 
cubiti,  229. 
biventer  cervicis,  202. 
brachialis  anticu?,  230. 
buccinator,  177. 
cer;ito-gl()ssus,  187. 
cervicalis  ascendcns,  201. 
circumflexus  palati,  191. 
coccyjreus,  222.  » 

complexus,  202. 
compressor  nasi,  173. 

urethrsB,  220. 
constrictor  inferior,  189. 
isth.  faucium,  188,  192. 
medius,  189. 
superior,  1S9. 
vaginae,  222. 
coraco-bracliialis,  229. 
corrugator  supercilii,  169. 
cremaster,  212. 
crico-arytcnoid  lat.,  510. 

posticus,  510. 
thyroideus,  510. 

51 


Muscles — continued. 
crureus,  251. 
cucullaris,  196. 
deltoid,  228. 
depressor  ang.  oris,  176. 
labii  inferioris,  176. 
labii  sup.  nla^que  nasi,  17S. 
depressor  oculi,  172. 
detrusor  urinrR,  559. 
diaphragm,  215. 
digastricus,  185. 
erector  clitoridis,  222. 
penis,  211). 
spinaB,  200. 
extensor  carpi  rad.  brev.  236. 
carpi  rad  long.,  236. 
carpi  uhiiiris,  238. 
digiti  minimi,  238. 
digitor.  brevis,  263. 
digitor.  com.  236, 
digitor.  longus-,  257. 
indicis,  239. 
ossis  metacarpi,  239. 
pollicis  proprius,  257. 
primi  inlernodii,  239. 
sec.  internodii,  239. 
flexor  accessorius,  266. 

brevis  digiti  minimi,  242. 
digiti  minimi  pedis,267. 
carpi  radialis,  232. 
ulnaris,  234. 
digitorum  brevis,  265. 

profundus,  234. 
sublimis,  233. 
longus  digit,  pedis,  261. 
longus  pollicis  manus,235. 
pedis,  260. 
ossis  metacarpi,  240, 242, 
pollicis  brevis,  241. 
pedis,  267. 
longus,  260. 
gastrocnemius,  258. 
gemellus  inferior,  218. 
superior,  248. 
genio-hyo  glossus.  186. 

hyoideus,  186. 
gluteus  niaximus,  246. 
medius,  247. 
minimus,  247. 
gracilis,  254. 
helicis  major,  480. 
minor,  480. 
hyo-glossus,  187. 
iliacus,  252. 
indicator,  239. 
infra-spinaius,  227. 
inter-costales  externi,  208. 
interni,  208. 
inter-ossei  manus,  243. 

pedis,  263,  267. 
inter. spinales,  204. 
inter-transversaies,  204. 
intracostales,  209. 
larynx,  of  the,  510. 


602 


Muscles — coniinued. 

latissimus  dorsi,  196. 
laxator  tympini,  483. 
levator  anguli  oris,  175. 

scapulae,  197. 
ani,  321. 

glanduloB  thyroid.,  514. 
labii  inferioris,  176, 
SLiperioris,  174. 
sup.  alseq.nasi,  174. 
menti,  176. 
palati,  191. 
palpebrsB,  171. 
levatores  costarum,  203. 
lingualis,  187, 
longissimus  dorsi,  200. 
longus  colli,  194. 
lumbricales  manus,  242, 

pedis,  266. 
mallei  externns,  483. 
iiiternus,  482. 
masseter,  176. 
multifidus  spinEB,  203. 
mylo-hyoideus,  185. 
myrtiformis,  175. 
obliquus  abdom.  ext.  210. 
abdom.  int.,  211. 
capitis  inferior,  203. 
superior,  20'i. 
oculi  inferior,  172. 
superior,  172. 
obturator  externus,  249. 
internus,  248. 
occipito-frontalis,  167. 
omo-hyoideus,  184. 
opponens  digit,  min.  242. 

poUicis,  240. 
orbicularis  oris,  174. 

palbebrarum,  169. 
palato-glossus,  188,  192. 

pharyngeus,  190, 192. 
palmaris  brevis,  242. 
longus,  232. 
pectineus,  253. 
pectoralis  major,  225. 
minor,  225. 
^eroneus  brevis,  263. 
longus,  262. 
tertius,  257. 
plantaris,  259. 
platysma-myoides,  181. 
popliteus,  260. 
pronator  quadratus,  235. 
radii  teres,  232, 
psoas  magnus,  253. 

parvus,  215. 
pterygoideus  ext.,  178. 
int.,  178. 
pyramidalis  abdom.,  214. 

nasi,  173. 
j)yriformis,  247. 
quadratus  femoris,  249. 

lumborum,  215. 
menti,  176. 


Muscles — continued. 

rectus  abdominis,  214. 

capitis  ant.  maj.,  193. 
min.,  193. 
lateralis,  203. 
post,  maj.,  203. 
min.  203. 
femoris,  251. 
oculi  externus,  172. 
inferior,  171. 
internus,  172. 
superior,  171. 
retraliens  aurem,  179. 
rhomboideus  major,  197. 
minor,  197. 
risorius  Santorini,  181. 
sacro-lumbalis,  200. 
sartorius,  250. 
scalenus  anticus,  193. 
posticus,  194. 
semi-spina!is  colli,  202. 
dijrsi,  202. 
semi-membranosu,«,  255. 
semi-tendinosus,  255. 
serratus  magnus,  226. 

posticus  jnf ,  199. 
sup.,  199.- 
soleus,  260. 
sphincter  ani,  221. 

internus,  221. 
spinalis  dorsi,  200. 
splenius  capitis,  199. 

colli,  199. 
stapedius,  483. 
sterno-hyoideus,  183. 

mastqideus,  181. 
thyroideus,  183. 
stylo-glossus,  188. 
hyoideus,  185. 
pharyngeus,  190. 
subclavius,  226. 
subcrureiis,  251. 
subscapularis,  226. 
supinator  brevis,  238. 
longus,  236. 
supra-spinales,  204. 
supra-spinatus,  227. 
temporal,  177. 
tensor  palaii,  191. 
tarsi,  170. 
tympani,  482. 
vaginae  fcm.  250. 
teres  major,  228. 
minor,  227. 
thyro-arylenoideus,  510. 
epiglottideus,  511. 
hyoideus,  183. 
tibialis  anticus,  2.17. 
posticus,  261. 
trachelo  mastoideus,  202. 
tragicus,  480. 
transversalis  abdom.,  213. 

colli,  201. 
transvcrsus  auris,  480. 


INDEX. 


603 


Muscles — continued. 

transversus  pedis,  267. 

perinei,  219,  222. 
trapezius,  196. 
triangularis  oris,  176. 

stern i,  210. 
triceps  extens.  cruris,  258. 
cubiti,  230. 
ureters,  of  the,  556. 
vastus  externus,  251. 
inteinus,  251. 
zygomaticus  tnajor,  175. 
tiiinor,  175. 
Muscular  fibre,  164. 
Musculi  peclinati,  500. 
Myolemma,  164. 
Myopia,  475. 

N. 

Naboth,  ovula  of,  574. 

Nagel,  Mr.,  researches  of,  576. 

Nails,  495. 

Nares,  527. 

Nasal  duct,  478. 

fosspe,  82,  466. 
Nasmyth,  Mr.,  researches  of,  85. 
Nates  cerebri,  398. 
Nerves. 

general  anatomy,  382. 
abducentes,  415. 
accessorius,  424. 
■  acromialcF,  432. 
auditory,  413,  490. 
auricularis  anterior,  429. 
niagnus,  431. 
posterior,  418. 
buccal,  428. 
cardiac,  423. 
cardiaciis  inferior,  460. 
inasnus,  460. 
njedins,  460. 
minor,  461. 
superior,  460. 
cervical,  430. 
cervico-facial,  418. 
chorda  tympani,  418,  456. 
ciliary,  426. 
circuinfle.v,  440. 
clavicularcs,  4.32. 
cochlear,  490. 

communicans  noni,  416,  432. 
peronei,  452. 
poplitei,  450. 
cranial,  411. 
crural,  444. 
cutaneous  ext.  branch,  436. 

ext.  femoralis,  444. 
int.  brachialis,  436. 

minor,  436. 
post,  femoralis,  449. 
spiralis,  439. 
dental  anterior,  427. 
inferior,  429. 
posterior,  427. 


Nerves — continued. 

desccndens  noni,  416. 
digastric,  418. 
dorsal,  440. 
eiirjith  pair,  420. 
facial,  417. 
femoral,  444. 
fifth  pair.  424. 
first  pair,  412. 
fourti)  pair,  417. 
frontal,  426. 
gastric,  424. 
genito-crural,  443. 
glosso-pharyngeal,  420. 
gluteal,  448. 

iriftrior,  448. 
gustatory,  428. 
hypo-glossal,  416. 
ilio-scrotal,  443. 
inferior  maxillary,  428. 
infra-trochlear,  426. 
inguino-cutaneous,  443. 
intercnstal,  441. 
inlercostoiiumeral,  441. 
inter-osseous  anterior,  437. 
posterior,  440. 
ischiaticus  major,  449. 
minor,  448. 
Jacobson's,  421. 
lachrymal,  426. 
laryngeal  inferior,  423. 

super.,  422,  459. 
lingual,  416. 
lumbar,  442. 
lumbo-sacral,  446. 
masseteric,  428. 
maxillaris  inferior,  428. 
superior,  427. 
median,  436. 
molles,  460. 
motores  oculorum,  414. 
rausculo-cutan.,  arm,  436. 
IcLS  443. 
musculo-spiral,  439. 
mylo-hyoidean,  429. 
n;isal,  426. 
obturator,  445. 
occipitalis  major,  433. 
minor,  432. 
olfactory,  412. 
ophthalmic,  425. 
optic,  412. 
orbital,  427. 
palatine  anterior,  455. 

posterior,  456. 
palmar,  deep,  4311. 

superficial,  437,  439. 
pathetici,  417. 
perforans  Casserii,  436. 
perineal,  448. 
pcroneocutaneous,  453. 
peroneal,  452. 
pctrosus  minor,  457. 
pharyngeal,  422,  459. 
phrenic,  432. 


604 


Nerves — continued. 

plantar  external,  452. 
internal,  451. 
pnenmoofustrie,  421.. 
poplileal,  449. 
porlio  dura,  417. 

mollis,  413. 
pteryfToid,  428. 
pudend.ilis,  448. 
pudic  inti  iiial,  448. 
pulinnnary,  424. 
radi.il,  439. 
recuri-ent,  423. 
respiratory  external,  435. 
sacral,  41G. 

.saphenous  external,  450, 
long,  445. 
short,  445. 
second  pair,  412. 
sixth  piir,  415. 
spinal,  429. 
spirTdl  accessory,  424. 
si>lanclinicus  major,  462. 
minor,  462. 
stylohyoid,  418. 
sub-occipital,  432. 
sub.scaiiul  ir,  435. 
superficialis  colli,  431. 

cordis,  460. 
supeiior  ma.xillary,  427. 
supra-orbitil,  427. 
scajjular,  435. 
trochlear,  426. 
sympalhcticus  major,  453. 
minor,  419. 
temporal,  428. 
temporo-tiici  il,  418. 
malar,  427. 
third  pair,  414. 
thoracic  l^ng^.,  435, 
short,  435. 
tibialis  anticus,  452. 
po-ticus,  451. 
triflic'al,  424. 
tri;.'cminiis,  424. 
troclileari-,  417. 
tympanic  421. 
ulnar,  438. 
vagus,  421. 
vestibular,  490. 
Vidian,  456. 
Neurilemma,  386. 
Nipple,  579. 
Nose,  464. 
NymphaD,  578. 


O, 


fEsophngus,  509,  .527. 
Omentum,  ga'iro-siilonic,  522. 

great,  522. 

lesser,  521. 
Omphalo-niescntcric  ves-cls,  574. 
Optic  commi.s.^ure,  402. 


Optic  thalami,  394,  397. 
Orbiculare  os,  481. 
Orbits,  81. 

Ossicula  audifus,  481. 
Ossification,  41, 
Ostium  abdominalo,  432. 

ntcrinum,  575. 
Otoconites,  490. 
Ovaries,  577. 
Ovula  Graafiana,  577. 
Naboth,  of,  574. 

P, 

Pacchionian  glands,  388, 
Pahfe,  524. 
Palmar  arch,  322. 
Palpebrcs,  475. 
Palpebral  ligaments,  476. 

sinuses,  477. 
Pancreas,  547. 
Panizza,  researches  of,  458. 
PapillfB  of  the  nail,  495. 
of  the  skin,  493. 
of  the  tongue,  491. 
caiyciforines,  491. 
circunivollatae,  491. 
conicfe,  491. 
filif  irmes,  491. 
fungiformes,  431. 
Parotid  s;land,  525. 
Pelvis,  109. 

viscera  of,  560. 
Penis,  563. 
Pericardium,  497. 
Perichondrium,  41. 
Pericranium,  41. 
Periosttum,  4  I. 
Peritoneum,  518. 
Perspiratory  ducts,  496. 
Pes  accessorius,  395. 
anscrinus,  418. 
hippocampi,  395. 
Petit,  notice  of,  474. 
Peyer,  notice  of,  536. 
Pcycr's  glands,  536. 
Ph.ilangc-,  105. 
Pharynx,  527. 
Pia  mater,  391,408. 
Pigmcnluiri  ni/;rum,  470. 
Pillars  of  the  |):ilatc,  525. 
Pineal  gland,  3.18. 
Pinna,  479. 
Pituitary  gland,  402. 

membrane,  466. 
Pleura,  517. 
Plexus,  aortic,  463. 
axillary,  433. 
brachial,  433. 
cardiic,  461. 
carotid,  457. 
cavernous,  4.'/8. 
cervical  anterior,  431. 
posterior,  433. 


605 


Plexus,  choroid,  394,  399. 

coeliac,  4G2. 

coronary,  461. 

gastric,  462. 

hepatic,  462. 

hypogastric,  463. 

lumbar,  442. 

mesenteric  inferior,  462. 
superior,  462. 

oesophageal,  424. 

pliarj'ngeal,  422. 

phrenic,  462. 

prostatic,  365. 

pterygoid,  354. 

puhnonary,  424,  461. 

renal,  462. 

sacral,  446. 

solar,  462. 

spermatic,  463. 

splenic,  462. 

submaxilliry,  429. 

supra-renal,  462. 

uterine,  365. 

veitebral,  460. 

vesical,  365. 
Plica  scniUunuris,  477. 
Plicae  longitudinales,  573. 
Pncumogastric  lobule,  400. 
Polypus  ol'the  heart,  499. 
Poiiium  Adami,  508. 
Pons  Tarini,  403. 
Varolii,  403. 
Pores,  4  )6. 
Portal  vein,  369,  541. 
L'..rtio  dura,  417. 

mollis,  413. 
Porus  opticus,  468. 
I'ou[)art's  ligament,  211. 
Prepuce,  563. 
Presbyopia,  475. 

Processus  e  cercbello  ad  testes,  401. 
clavatus,  409. 
vermiformes,  400. 
Proinontory,  483. 
Prostate  gland,  565. 
Prostatic  urethra,  565. 
Protuberantia  annularis,  403. 
Pulmonary  artery,  540. 

plexuses,  540. 
sinuses,  503. 
veins,  370. 
Puncta  lachrynialia,  475. 

vasculosa,  392. 
Pupil,  470. 

Purkinjc,  corpuscules  of,  39. 
Pylorus,  ^28. 
P\  ramid,  485. 
Pyramids,  anterior,  403. 
posterior,  399. 
of  Wistai',  65. 

R. 

Raphe,  corporis  callosi,  3. .2. 


Receptaculum  chyli,  379. 
Rectum,  531. 
Regions,  abdominal,  518. 
Reil,  island  of,  402. 
Respiratory  nerves,  417. 

tract,  417. 
Rete  mucosum,  494. 

testis,  568. 
Retina,  471. 
Ribcs,  gan'jiion  of,  455. 
Rima  glotlidis,  511. 
Ring,  external  abdominal,  211. 

femoral,  281. 

internal  abdominal,  273. 
Rugffi,  567. 
Ruysch,  notice  of,  470. 


S. 


Sacculus  laryngis,  512. 
proprius,  4>8. 
Salivary  glands,  525. 
Saphenous  opening,  280. 

veins,  3d3. 
Scala  tympani,  487. 
vestibuli,  487. 
Scarf-skin,  494. 
Scarpa,  notice  of,  490. 
Schindylesis,  122. 
Schneider,  notice  of,  466. 
Sclmeidcrian  membrane,  466. 
Sclerotic  coat,  467. 
Scrotum,  567. 

Searle,  Mr.,  researches  of,  504. 
Sebaceous  glands,  496. 
Semicircular  canals,  486. 
Semilunar  fibro-cartilages,  154. 

valves,  502. 
Septum  auricularum,  499. 
crurale,  282. 
lueidum,  396. 
pccliniforme,  5G.3. 
scroti,  567. 
Serous  membrane,  structure,  522, 
Sesamoid  bones,  120. 
Sheath  of  the  rectus,  214. 
Sigmoid  valves,  5i)4. 
Slnu^cs,  strmture,  353. 
Sinus,  aoriic,  5!)4. 
basilar,  359. 
cavernous,  353. 
circular,  359. 
fourth,  357. 
lateral,  358. 

longitudinal  inferior,  357. 
superior,  356. 
occipital  anterior,  357. 
posterior,  357. 
petrosal  in  crior,  359. 
superior,  359. 
pocularis,  5'i5. 
prostatic,  560. 
[luliii'  nary,  503. 
rectus  or  straight,  357. 


606 


INDEX. 


Sinus,  transverse,  359. 

Skeleton,  42. 

Skiri,  492. 

Skull,  50.    • 

Socia  parotidis,  526. 

Soemmering',  notice  of,  472. 

Soft  palate,  524. 

Spermatic  canal,  274. 
cord,  567. 

Spheno-maxillary  ganglion,  455. 

Spigel,  notice  of,  542. 

Spinal  cord,  4U7. 
nerves,  429. 
veins,  .368. 

Spleen,  552. 

Spongy  part  of  the  urethra,  566. 

Stapes,  481, 
Stenon,  notice  of,  492. 
Stenon's  duct,  525. 
Stomach,  528. 
Strife,  muscular,  164. 
Sub-arachnoidean  fluid,  390. 
space,  390. 
tissue,  390. 
Sublingual  gland,  525. 
Submaxillary  gland,  526. 
Substantia  perforata,  402. 
Sulcus  hepatis,  541. 

longitudinal  chordafe  spinal.,  409. 
Supercilia,  475. 
Superficial  fascia,  270. 
Supra-renal  capsules,  553. 
Suspensory  ligament,  liver,  540. 
penis,  566. 
Sutures,  74. 
Sylvius,  notice  of,  391. 
Sympathetic  nerve,  453. 
Symphysis,  122. 
Synarthrosis,  122, 
Synovia,  125. 
Synovial  membrane,  125, 


T, 


Tapetum,  470. 

Tarin,  Peter,  notice  of,  .394. 

Tarsal  cartilages,  476. 

Tarsus,  115. 

Teeth,  83. 

Tcndo  Achillis,  258. 

oculi,  169. 
Tendon,  1G2. 
Tenia  scmicircnl.iris,  394. 

Tarini,  394. 
Tentorium  cerehclli,  .389. 
Testes  cerebri,  398. 
Testicles,  568. 

descent,  588. 
Thalami  optici,  394,  397. 
Thebcsius,  notice  of,  500. 
Theca  vurlcbrulis,  408. 
Thoracic  duct,  379. 
Thorax,  41)7. 
Tiiymus  glund,  586, 


Thyro-hyoid  membrane,  509, 
Thyroid  axis,  310. 

cartilage,  508. 
gland,  513. 
Tod,  Mr.,  researches  of,  480. 
Tongue,  4i)l. 
Tonsils,  525. 

cerebelli,  401. 
Torcular  Herophili,  357. 
Trachea,  513. 
Tractus  motorins,  414. 

respiratorius,  417. 
Tragus,  479. 

Triangles  of  the  neck,  184, 
Tricuspid  valves,  501. 
Trigone  vesicale,  567. 
Trochlearis,  172. 
Tuber  cinereum,  402. 
Tubercula  quadrigemina,  398. 
Tuberculum  Lovveri,  500. 
Tubuli  lactiferi,  572. 

seminiferi,  567. 
uriniferi,  556. 
Tunica  albuginea  oculi,  467. 
testis,  569, 
erythroides,  570. 
nervea,  572. 
Ruyschiana,  471. 
vaginalis,  569. 
vasculosa  testis,  568. 
Tympanum,  480. 
Tyrrell,  Mr.,  researches  of,  221, 
Tyson's  glands,  562, 

U. 

Umbilical  region,  518. 
Urachus,  558. 
Ureter,  552. 
Urethra,  female,  573. 

male,  566. 
Uterus,  575. 

Utriculus  communis,  488. 
Uvea,  471. 
Uvula  cerebelli,  401. 

palati,  525. 

vesicsE,  558. 

V. 

Vagina,  578. 

Valve,  aiachnoid,  399. 

Bauhini,  53.3. 

coronary,  500. 

Eustachian,  500. 

ilco-caccal,  533. 

mitral,  504. 

pyloiic,  532. 

rectum,  of  the,  538. 

semilunar,  502,  501. 

tricuspid,  501. 

Vicussons,  of,  399. 
Valvnla3  cormivcnics,  532. 
Varolius,  notice  ofj  403, 


607 


Vasa  efferentia,  569. 
lactea,  379. 

lymphiitica,  379. 

pampiniformia,  570. 

recta,  568. 

vasornm,  287. 
Vasculum,  aberrans,  569. 
Vas  deferens,  569. 
Veins. 

structure,  353. 

angular,  354. 

auricular,  355. 

axillary,  36'2. 

azygos  major,  367. 
minor,  367. 

basilic,  361. 

cardiac,  368. 

cava  inferior,  365. 
superior,  364. 

cephalic,  361. 

cerebellar,  356. 

cerebral,  356, 

coronary,  368. 

corporis  striata,  394. 

diploe,  355. 

dorsalis  penis,  365. 

dorsi-spinal,  368. 

emulgent,  367. 

facial,  354. 

femoral,  363, 

frontal,  354. 

Galeni,  356. 

gastric,  369. 

hepatic,  367. 

iliac,  365,  366. 

innominata,  364. 

intercoftiil  superior,  268. 

jugular,  359. 

lumbar,  366. 

mastoid,  355. 

maxillary  internal,  354. 

median,  362. 

basilic,  362. 
ci.!phalic,  362. 

medulli-spinal,  368. 

meningo  rachidian,  368. 

mesenteric  inferior,  369. 
superior,  369. 

occipital,  355. 

ovarian,  366. 

parietal,  356. 

popliteal,  363. 

portal,  369. 

profunda  femoris,  363. 

prostatic,  365. 

pulmonary,  370,  503. 

radial,  361. 

renal,  367. 

salvatella,  361. 


Veins — continued. 

saphenous  external,  363. 
internal,  363. 
spermatic,  366. 
spinal,  368. 
splenic,  369. 
subclavian,  362. 
temporal,  355. 
temporo-maxillary,  355. 
Thebesii,  369. 
thyroid,  360. 
ulnar,  361. 
uterine,  365. 
vertebral,  360,  368. 
vesical,  365. 
Velum  inlerpositum,  391,  396. 
pendulum,  palati,  402. 
Venae  comites,  352. 
Galeni,  397. 
vorticosae,  470. 
Ventricle  of  Aranlius,  399. 
Ventricles  of  the  brain,  396. 
fifth,  396. 
fourth,  399. 
lateral,  392. 
third,  398. 

ofthe  heart,  500,503. 
of  the  larynx,  512. 
Vermiform  process,  400. 
Vertebral  aponeurosis,  199. 

column,  43. 
Veru  montanuijp,  565. 
Vesiculoe  seminales,  569. 
Vestibule,  485. 
Vestibulum  vaginsB,  578. 
Vibrissas,  466. 

Vidius  Vidus,  notice  of,  456. 
Vieussens,  notice  of,  399. 
Villi,  507. 

Vitreous  humour,  473. 
Vulva,  578, 

W. 

Wharton,  notice  of,  492. 
Wharton's  duct,  526. 
Wilhs,  notice  of,  388, 
Wilson's  muscles,  220. 
Winslow,  notice  of,  521, 
Wistar,  pyramids  of,  65. 
Wrisberg,  nerve  of,  436. 

Z. 

Zinn,  notice  of,  473, 
Zonula  cilinris,  473. 
of  Zinn,  473, 
Zygoma,  56. 


THE  £ND. 


TO  THE  MEDICAL  PROFESSION. 


LEA  AND  BLANCHARD  present  a  condensed  list  of  Books  published  and  preparing  for  publication  by 
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1  vol.  Svo.,  527  pages. 
Todd's  Cyclopaedia  of  Anatomy  and  Physiology,  to  be 

published  hereafter. 
Walshe's  Diagnosis  of  the  Diseases  of  the  Lungs,  1 

vol.  12mo.,  310  pages. 
Watson's    Principles  and  Practice  of  Physic,  1  vol. 

Svo..  920  very  large  pages. 
Wilson's  Huinan  An^itpmy,  with  outs,  1  vol.  Svo.,  a 

new  aiid  irnproved  e(lition.  008  pages. 
Wilson's  Dissector,  or  Practical  and  Surgical  Anato- 
my, by  Goddard,  with  juis.  1  vol.  12mo.,444  pages. 
Wilson  on  the  Skin,  1  vpl.  Svo.,  370  pages. 
Youatt  pn  the  Horse,  by  Skinner,  with  cuts,  448  pages,. 

1  vol.  Svo. 
Youatt  and  Dlater's  Cattle  Doctor,  1  vol.  12mo.,  with 

cuts,  282  pages. 
Williams's  Pfttholog>',  or  Principles  of  Medicine,  1  vol, 

Svo.,  3^-3  pages. 
Williams's  I^ectures,  on  Stomach,  Brainy  &c.,  1  vol 

8vo.,  preparing. 
Williams  on  Respiiatpry  Organs,  by  Clymei,  1  vol 

Svo.,  500  p^ges. 


They  have  other  works  ia  preparation,  not  includled  in>  this  hst,         3 


JUST  ISSUED  BY  LEA  &  BLANCHARD. 


WILLIAMS  AND  CLYMER  ON  THE  RESPIRATORY 

GROANS,  ETC. 


/  

A    TREATISE 

ON  THE 

DISEASES  OF  THE   RESPIRATORY  ORGANS, 

INCLUDING 

THE  TRACHEA,  LARYNX,  LUNGS,  AND  PLEURA. 
Br  CHARLES  J.  B.  WILLIAMS,  M.  D., 

Consulling  Physician  to  the  Hospital  for  Consumption  and  Diseases  of  this  Chest;  Author  of 

"Principles  of  Medicine,"  &c.  &c. 

WITH  NUMEROUS  ADDITIONS  AND  NOTES. 

By  MEREDITH  CLYMER,  M.  D., 

Physician  to  the  Philadelphia  Hospital. 

In  One  neat  8vo.  Volume,  with  Cuts. 


NOW  READY, 

ANOTHER  VOLUME  OF  THE  SERIES  OF  SIR  ASTLEY 
COOPER'S  WORKS. 


ON  THE  STRUCTURE  AND  DISEASES  OF  THE  TESTIS. 

ILLUSTRATED   BY    120   FIGURES. 

From  the  Second  London  Edition 
By  BRANSBY  B.  COOPER,  Esq. 

"The  republication  of  this  splendid  volume  supplies  a  want  that  has  been  very  severely  felt  from  the  el- 
haustion  of  the  first  edition  of  it.  .  .  .  The  extraordinary  merits  of  thi.s  treatise  have  been  so  long  and  so  univer- 
sally acknowledged,  that  it  would  be  a  work  of  supererogation  to  represent  them  in  our  pages.  The  practicai 
surgeon  who  is  not  master  of  its  contents,  cannot  be  fully  aware  of  the  imperfection  of  his  own  knowledge  om 
the  subject  of  diseases  of  the  testicle." — British  and  Foreign  Medical  Review. 

AND 

ON  THE  ANATOMY  OF  THE  THYMUS  GLAND. 

ILLUSTRATED  BY  57  FIGURES. 

The  two  works  together  in  one  beautiful  imperial  octavo  volume,  illus- 
trated in  the  best  style  of  lithography,  and  printed  and  bound  to  match 
the  author's  great  work  on  Hernia,  lately  pubhshed. 


BRIGHAM  ON  MENTAL  EXCITEMENT. 


REMARKS  ON  THE  INFLUENCE  OF 

MENTAL  CULTIVATION  AND  MENTAL  EXCITEMENT 

UPON  HEALTH. 

Third  Edition. 

By  a.  BRIGHAM,  M.D., 

Superintendent  and  Physician  of  liie  State  Lunatic  Asylum,  Utica,  N.  Y. 

In  One  Vol.  12mo. 

Thispopularlillle  work  has  been  reprinted  in  London,  Edinburgh  and  Glasgow.  In  this  third  American 
Edition  the  author  has  included  all  the  improvements  of  the  three  British  editors,  and  has  also  added  new 
matter  which  brings  it  up  to  the  day,  and  renders  it  still  more  worthy  of  the  favour  it  hasao  long  enjoyed. 

4 


NOW  READY, 
MEIGS'S    TRANSLATION 

OF 

COLOMBAT  DE  L1SEBE  mi  THE  DISEASES  OF  FEMALES. 
A  TREATISE  ON  THE  DISEASES  OE  EEMALES, 

AND  ON 

THE  SPECIAL  HYGIENE  OF  THEIR  SEX. 

WITH  NUMEROUS  WOOD-CUTS. 
BY   COLOMBAT   DE   L'lSER  E,  M.  D., 
Chevalier  of  the  Legio7i  of  Honour;  late  Surgeon  to  the  Ho---pilul  of  the  Rue  de  Valois,  devotid  to  the 
Diseases  of  Females.  Src    t5"C- 

TRANSLATED,  WITH  MANY  NOTES  AND  ADDITIONS, 
By   C.  D.   MEIGS,  M.D., 

Professor  of  Obstetrics  and  Diseases  of  Women  and  Cliildren  in  the  Jefferson  Medical  College,  Sf-c.  ^-c. 

In  One  Volume,  Svo. 

The  notes  and  addenda  of  Professor  Meigs  are  very  extensive  and  valuable,  bringing  the  whole  up  to  the  day 
of  publication,  and  giving  whatever  maybe  necessary  with  regard  to  American  practice.  It  forms  a  large 
octavo  volume  of  near  7U0  pages,  with  numerous  wood-cuts. 

LATELY   PUBLISHED. 
A  NEW  EDTnON  OF 

TTILeOIT'^   HXJMAH   AITATOMY. 

MUCH    IMPROVED. 

A   SYSTEM    OF   H'UftlAN   ANATOMY, 

GENERAL  AND  SPECIAL. 
By    ERASMUS    W  I  L  S  0  N,  M.  D., 
SECOND  AMERICAN  EDITION. 
EDITED  BY 

PAUL  B.  GODDARD,  A.M.,  M.D., 

Lecturer  on  Anatomy,  and  Demonstrator  in  the  University  of  Peimsylvania,  ^-c. 
WITH  OVER  TWO  HUNDRED  ILLUSTRATIONS, 

Beautifully  Printed  from  the  Second  London  Edition. 

From  the  Preface  to  the  Second  American  Editimi. 
"The  very  rapid  sale  of  the  first  edition  of  this  work,  is  evidence  of  its  appreciation  by  the  profession,  and  is 
taosl  gratifying  to  the  author  and  American  editor.  In  preparing  the  present  edition  no  pains  have  been  spared 
to  render  il  as  complete  a  mannal  of  Anatomy  lor  the  medical  student  as  possible.  A  chapter  on  Histology  has 
therefore  been  prefixed,  and  a  considerable  number  of  new  cuts  added.  Among  the  latter,  are  some  very  fine 
ones  of  the  nerves  which  were  almost  wlioUy  omitted  from  the  original  work.  Great  care  has  also  been  taken 
tia  have  this  edition  correct,  and  the  cuts  carelully  and  beautit'ully  worked,  and  it  is  confidently  believed  that  it 
will  give  satisfaction,  oflering  a  farther  inducement  to  its  general  use  as  a  Text  Book  in  the  various  Colleges." 

L.\TELY  PUBLISHED, 

A  NEW  AND  MUCH  IMPROVED  EDITION  OF 


UI  T  T'S     SURG 


THE  PRI^GIPLES  km  PeMTIOE  OF  MOOEi^  SOiOERY. 

By  ROBERT  DRUITT,  Surgeon. 

FROM    THE    THIRD    LONDON    EDITION. 

ILLUSTRATED  BY    ONE    HUNDRED    AND  .FIFTY-THREE   WOOD    ENGRAVINGS. 

WITH  NOTES  AND  COMIMENTS 

By  JOSHUA  B.  FLINT,  M.  M.  S.  S. 

In  One  Volume,  8vo. 

"An  unsurpassable  compendium  not  only  of  surgical  but  of  medical  practice."— Lojirfon  Medical  Gazette. 

"It  may  be  said  with  truth  that  the  work  of  Mr.  Druiit  altbrds  a  complete,  through  brief  and  condensed  view, 
of  the  entire  field  of  modern  surgery.  We  know  of  no  work  on  tlie  same  suhject,  having  the  appearance  of 
a  manual,  which  includes  so  many  topics  of  interest  to  the  surgeon  ;  and  the  terse  manner  in  which  cacli  has 
been  treated  evinces  a  most  oiviahie  quality  of  mind  on  the  part  of  the  author,  who  seems  to  liave  an  innate 
power  of  searching  out  and  gva.<ping  the  leatlingfacls  and  tVaturesof  the  most  elaborate  productions  of  the  pen. 
Notwithstanding  various  weedings  and  alterations,  we  find  that  there  are  nearly  fil'ly  pages  of  additional  mat- 
ter in  the  present  volume,  and  evidently  much  has  been  done  by  both  author  and  puldishers  to  sustain  the 
reputation  already  acquired.  The  wood-cuts  have  been  greatly  increased  innamlier,  and  the  pencil  and  graver 
of  William  Hagg  have  added  brilliancy  to  this  portion  of  the  hook.  it  »  *  It  is  a  nsei'ul  handbook 
for  the  practitioner,  aiul  we  should  deem  a  teacher  of  surgery  unpardonable  who  did  not  recommend  it  to  his 
pupils.  Inourpwnoiiinion,  it  is  admirably  adapted  to  the  wants  of  the  student;  and  with  congratulations  to 
tlie  author  and  publishers — for  the  latter  deserve  much  credit  tor  the  handsome  appearance  of  the  volume — on 
the  success  of  their  undertaking,  we  leave  the  present  edition  as  a  piquant  proportion  of  the  ample  store  of 
knowledge  which  it  is  the  good  Ibrtune  of  the  rising  youth  in  the  protessiou  to  be  so  cheaply  provided  with  in  the 
present  day." — Provincial  Med  Journal. 


NOW  AT  PRESS, 


MENTAL  MALADIES, 

CONSIDKRHDIN  RELATION  TO 

MEDICINE,  HYGIENE,  AND  MEDICAL  JURISPRUDENCE. 
By  E.  ESQUIROL, 

Principal  Physician  of  ihe  "Maison  Koysilp  des  Alien^s  de  Cliiirpnion,"  <fcc.  &c. 

TRANSLATED,    WITH    ADDITIONS, 
By  E.  K.  hunt,  M.  D., 

Ill  One  Volume,  Svo. 

Tliis  great  work  has  long  been  considered  as  the  highest  authority  on  the  important  points  of  which  it  treats. 
The  notes  and  additions  of  the  Translator,  Dr.  Hunt,  will  be  numerous  and  valuable,  bringing  the  scientific 
and  medical  pans  of  the  treatise  up  to  the  day  of  publication,  and  eml)odying  the  results  of  the  milder  and 
improved  American  practice  in  the  treatment  of  the  insane. 

NOW  READY, 

ASHV/ELL  ON  THE  JSEASES  OF  FEMALES. 

A  PRACTICAL  TREATISE 

ON  THE 

DISEASES   PECULIAR   TO   WOMEN, 

ILLUSTRATED   BY  CASES 
DERIVED  FROM  HOSPITAL  AND  PRIVATE  PRACTICE. 
By  SAMUEL  ASHWELL,  M.  D., 

Member  of  the  Royal  College  of  Physicians;  Obstetric  Physician  and  Lecturer  to  Guy's  Hospital,  &c. 
WITH  ADDITIONS, 

By  PAUL  BECK  GODDARD,  M.  D. 

In  One  Vol.  Svo. 

CONTENTS.— Part  I.— Functional  Diseases. 

Introductory  Remarks  on  the  Functional  Affections  of  the  Female  Sy.stem. — Chlorosis,  and  Illustrative  Cases. 
— Arnenorrhoea,  and  Iliuslrative  Cases.' — Emmenagogues.' — Dysmenorrhoea,  and  Illustrative  Cases.^-For- 
mulre  of  Remedies. — Profuse  Menstruation. — IVIeiiorrhagia,  and  Illustrative  Cases. — Leucorrhoea,  and 
Illustrative  Cases. — Inflammation  oi'  the  Cervix  Uteri,  and  Illustrative  Cases. — Formulfe  of  Remedies.— 
Aflections  attendant  on  the  decline  of  the  Catamenial  Function. — Hysteria. — Irritable  Uterus  or  Hysieral- 
gia,  and  Illustrative  Cases. 

Part  II. — Organic  Diseases. 

Of  the  Organic  Diseases  of  the  Internal  and  External  Female  Genitals. — General  Remarks  on  the  History 
and  ^fymptoms,  Diagnosis,  Pathology  and  Prognosis  of  the  Organic  Diseases  of  the  Uterine  System. — Of 
the  Tumours  of  the  Walls  of  the  Uterus,  characterized  by  Induration. — On  Premature  Labour  in  Preg- 
nancy complicated  with  Organic  Diseases,  and  Illustrative  Cases. — Organic  Diseases  of  the  Os  and  Cervix 
Uteri. — Congestion  of  the  Uterus. — Acute  Metritis. — Chronic  Metritis. — Cancer  of  the  Uterus,  and  Illus- 
trative Cases. — Simple  Ulceration  of  the  Cervix  and  Os  Uteri. — Corroding  Ulcer  of  the  Uterus. — Cauli- 
flower Excrescence  of  the  Uterus. — Occlusion  and  Rigidity  of  the  Cervix  Uteri,  and  Illustrative  Cases. 

Part  Hi. 

Organic  Diseases  of  the  Mucous  Membrane  of  the  Cavity  of  the  Uterus. — Polypusof  the  Uterus,  and  illu.strative 
Cases. — Di.splacemenlsof  the  Uterus. — Diseases  of  the  Ovaries. — Of  the  Diseases  of  the  External  Organs 
of  Generation  in  the  Female. 

Appendix. 

On  the  Morbid  consequences  of  undue  I^actation,  with  Illustrative  Cases. — Case  of  Pregnancy  complicated 
with  Abdominal  Tumours. — Induction  of  Premature  Labour,  &c.  &c. 


A  NEW  EDITION  OF 

CHURCHILL  ©N  FEMALES. 


THE    DISEASES    OF    FEMALES; 

INCLUniNfJ  THOSE  OF 

PREGNANCY  AND  CHILDBED, 

Br  FLEETWOOD  CHURCHILL,  M.D.,  ^ 

Aiilhoi-  of  "Theory  and  Practice  of  M'nlwifei-y,"  he.  he. 
THIRD  AMERICAN,  FRO.M  THE  SECOND  LONDON  EDITION. 

With  Illustrations.    Edited,  with  Notes, 

By  ROBERT  M.  HUSTON,  M.  D.,  &c.  &c. 
In  One  Volume,  Svo, 

"In  complying  with  the  demand  of  Ihe  profession  in  this  country  for  a  third  edition,  the  Editor  has  much  plea- 
sure in  tlie  opportunity  thus  alforded  of  presenting  the  vi^ork  in  its  more  perfect  form.  All  the  additional  refe- 
r*nc«B  and  iUuBiralions  contained  iu  the  English  copy,  are  retained  in  this." 

6 


A  nZAaiQlFZCETdrT  /^NJ}  CHEAP   VTOILE. 

SMITH  &  HORNER'S  ANATOMICAL  ATLAS. 

Just  Published,  Price  Five  Dollars  in  Parts. 


AN 

ANATOMICAL    ATLAS 
ILLUSTRATIVE  OF  THE  STRUCTURE  OF  THE  HUMAN  BODY. 

BY  HENRY  H.  SMITH,  M.  D., 

Fellow  of  the  College  of  Physicians,  S;c. 
UNDER  THE  SUPERVISION  OF 

WILLIAM  E.  HORNER,  M.  U., 

Professor  of  Anatomy  in  the  University  of  Pennsylvania. 

In  One  large  Volume,  Imperial  Octavo. 

This  work  is  but  just  completed,  having  been  delayed  over  the  time  intended  by  the  great  difficulty  in  giving 
to  the  illustrations  the  desired  finish  and  perfection.    It  consists  of  five  parts,  whose  contents  are  as  follows: 

Part     I.  The  Bones  and  Ligaments,  with  one  hundred  and  thirty  engravings. 

Part   II.  The  Muscular  and  Dermoid  Systems,  with  ninety-one  engravings. 

Part  III.  The  Organs  of  Digestion  and  Generation,  with  one  hundred  and  ninety-one  engravings. 

Part  IV.  The  Organs  of  Respiration  and  Circulation,  with  ninety-eight  engravings. 

Part   V.  The  Nervous  System  and  the  Senses,  with  one  liundred  and  twenty-six  engravings. 
Formuig  altogether  a  complete  System  of  Anatomical  Plates,  of  nearly 

SIX   HUNDRED   AND  FIFTY   FIGURES, 
executed  in  the  best  style  of  art,  and  making  one  large  imperial  octavo  volume.    Those  who  do  not  want  it  in 
parts  can  have  the  work  bound  in  extra  cloth  or  sheep  at  an  extra  cost. 

This  work  possesses  novelty  both  in  the  design  and  the  f-xecution.  It  is  the  first  attempt  to  apply  engraving 
on  -wood,  on  a  large  scale,  to  ihe  illustration  of  human  anatomy,  and  the  beauty  of  the  parts  issued  induces  the 
publishers  to  flatter  themselves  with  the  hope  of  the  perfect  success  of  their  undertaking.  The  plan  of  the 
work  is  at  once  novel  and  convenient.  Each  page  is  perfect  in  itself,  the  references  being  immediately  under 
the  figures,  so  that  the  eye  takes  in  the  whole  at  a  glance,  and  obviates  the  necessity  of  continual  reference 
backwards  and  forwards.  The  cuts  are  selected  from  the  best  and  most  accurate  sources ;  and,  where  neces- 
sary, original  drawings  have  been  made  from  the  admirable  Anatomical  Collection  of  the  University  of  Penn- 
sylvania. It  embraces  all  the  late  beautiful  discoveries  arising  from  the  use  of  the  microscope  in  the  investi- 
gation of  the  minute  structure  of  the  tissues. 

In  the  getting  up  of  this  very  complete  work,  the  publishers  have  spared  neither  pains  nor  expense,  and  they 
now  present  it  to  Ihe  profession,  with  the  full  confidence  that  it  will  be  deemed  all  that  is  wanted  in  a  scientific 
and  artistical  point  of  view,  while,  at  the  same  time,  its  very  low  price  places  it  within  the  reach  of  all. 

It  is  particularly  adapted  to  supply  the  place  of  skeletons  or  subjects,  as  the  profession  will  see  by  examining  the  list 
of  plates  now  anruxed. 


"These  figures  are  well  selected,  and  present  a  complete  and  accurate  representation  of  that  wonderful  fabric, 
the  human  body.  The  plan  of  this  Atlas,  which  renders  it  so  peculiarly  convenient  lor  the  student,  and  its 
superb  artistical  execution,  have  been  already  pointed  out.  We  must  congratulate  the  student  upon  the 
completion  of  this  atlas,  as  it  is  the  most  convenient  work  of  the  kind  that  has  yet  appeared;  and,  we  must 
add,  the  very  beautiful  manner  in  which  it  is  '  got  up'  is  so  creditable  to  the  country  as  to  be  flattering  to  our 
national  pride." — American  Medical  Journal. 

"This  IS  an  exquisite  volume,  and  a  beautiful  specimen  of  art.  We  have  numerous  Anatomical  Atlases, 
but  we  will  venture  to  say  that  none  equal  it  in  cheapness,  and  none  surpass  it  in  faithfulness  and  spirit.  We 
strongly  recommend  to  our  friends,  both  urban  and  suburban,  the  purchase  of  this  excellent  work,  for  which 
both  editor  and  publisher  deserve  tne  thanks  of  the  profession." — Medical  Exannner. 

"AVe  would  strongly  recommend  it,  not  only  to  the  student,  but  also  to  the  working  practitioner,  who, 
although  grown  rusty  in  the  toils  of  his  harness,  still  has  the  desire,  and  often  the  necessity,  of  relreshing  his 
knowledge  in  this  fundamental  part  of  the  science  of  medicine." — New  York  Journal  of  ISledicinc  and  Surg. 

_"  The  plan  of  this  Atlas  is  admirable,  and  its  execution  superior  to  any  thing  of  t)ie  kind  before  published  m 
this  country.  It  is  a  real  labour-saving  affair,  and  we  regard  its  publication  as  the  greatest  boon  that  could  be 
conferred  on  the  student  of  anatomy.  It  will  be  equally  valuable  to  Uie  practitioner,  by  affording  him  an  easy 
means  of  recalling  the  details  learned  in  the  dissecting  room,  and  which  are  soon  forgotten." — American  Medi- 
cal Journal. 

"It  is  a  beautiful  as  well  as  particularly  useful  design,  which  should  be  extensively  patronized  by  physicians, 
surgeons  and  medical  students." — Boston  Med.  and  Surg.  Journal. 

"  It  has  been  the  aim  of  the  author  of  the  Atlas  to  comprise  in  it  ttie  valuable  points  of  all  previous  works,  to 
embrace  the  latest  microscopical  observations  on  the  anatomy  of  the  tissues,  and  by  placing  it  at  a  moderate 
price  to  enable  all  to  acquire  it  who  may  need  its  assistance  in  the  dissecting  or  operating  room,  or  other  field 
of  practice." — Western  Journal  of  Med.  and  Surgery. 

''These  numbers  complete  the  series  of  this  beautiful  work,  which  fully  merits  the  praise  bestowed  upon  the 
earlier  numbers.  We  regard  all  the  engravings  as  possessing  an  accuracy  only  equalled  by  their  beauty, 
and  cordially  recommend  the  work  to  all  engaged  in  \he  study  of  anatomy." — i\Vio  York  Journal  of  Malicirie 
and  Surgery. 

"A  more  elegant  work  than  the  one  before  us  conld  not  easily  be  placed  by  a  physician  upon  the  table  of 
his  student." — Western  Journal  of  Medicine  and  Surgery. 

"We  were  much  pleased  with  Part  I,  but  the  Second  Part  gratifies  us  still  more,  both  as  regards  the  attract- 
ive nature  of  the  subject,  (The  Dermoid  and  Muscular  Systems.)  and  the  beautiful  artistical  execution  of  the 
illustrations.  We  have  here  delineated  the  most  accurate  microscopic  views  of  some  of  the  tissues,  as,  for 
instance,  the  cellular  and  adipose  tissues,  the  epidermis,  rete  mucosum  and  cutis  vera,  the  sebaceous  and 
perspiratory  organs  of  the  skin,  the  perspiratory  glands  and  hairs  of  the  skin,  and  the  hair  and  nails.  Then 
follows  the  general  anatomy  of  the  muscles,  and,  lastly,  their  separate  delineations.  AVe  would  recommend 
this  Anatomical  Atlas  to  our  readers  in  the  very  strongest  terras." — Nfio  York  Journal  of  Medicine  and  Suf 
fiery. 


LIST    OF 

THE  ILLUSTRATIONS 

EMBRACING 

SIX  HUNDEED  AND  THIETY-SIX  PIGUEES 

IN  SMITH    AND    HORNER'S    ATLAS. 


A  HlGHLY-TINISHED  ViEW  OF  THE  BoNES  OF  THE  HeAD, 

View  of  Cuvier's  Anatomical  Theatre, 


facing  the  title-page. 
.    .    .    .     vignette 


PART  I.— BONES  AND  LIGAMENTS. 

Fiff. 


Front  view  of  adult  skeleton. 

Back  view  of  adult  skeleton. 

FcEtal  skeleton. 

Cellular  structure  of  femur. 

Cellular  and  compound  structure  of  tibia. 

Fibres  of  compact  matter  of  bone. 

Conoenti'ic  lamellse  of  bone. 

Compact  matter  under  the  microscope. 

Haversian  canals  and  lacunx  of  bone. 

Vessels  of  compact  matter. 

Minute  structure  of  bones. 

Ossification  in  cartilage. 

Ossification  in  the  scapula. 

Puncta  ossificationis  in  femur. 

Side  view  of  the  spinal  column. 

Epipiij'ses  and  diaphysis  of  bone. 

External  periosteum. 

Punctum  ossificationis  in  the  head. 

A  cervical  vertebra. 

The  atlas.    21  The  dentata. 

Side  view  of  the  cervical  vertebra. 

Side  view  of  the  dorsal  vertebrse. 

A  dorsal  vertebra. 

Side  view  of  the  lumbar  vertebrse. 

Side  view  of  one  of  the  lumbar  vertebrse. 

Peipendicular  view  of  tlie  lumbar  vertebrse. 

Anterior  view  of  sacrum. 

Posterior  view  of  sacrum. 

The  bones  of  the  coccyx. 

Outside  view  of  the  innominatum. 

Inside  view  of  the  innominatum. 

Anterior  view  of  the  male  pelvis. 

Anterior  view  of  the  female  pelvis. 

Front  of  the  thorax.    36  The  first  rib. 

Genei-al  characters  of  a  rib. 

Front  view  of  the  sternum. 

Head  of  a  Peruvian  Indian. 

Head  of  a  Choctaw  Indian. 

Front  view  of  the  os  frontis. 

Under  surface  of  the  os  frontis. 

Intei'nal  surface  of  the  os  frontis. 

External  surface  of  the  parietal  bone.s 

Internal  surface  of  the  parietal  bone. 

External  surface  of  the  os  occipitis. 

Internal  surface  of  the  os  occipitis. 

External  surface  of  the  temporal  bone. 

Internal  surface  of  liie  temporal  bone. 

Internal  surface  of  the  sphenoid  bone. 

Anterior  surface  of  the  sphenoid  bone. 

Posterior  surface  of  the  ethmoid  bone. 

Front  view  of  the  bones  of  tlie  face. 

Outside  of  the  upper  maxilla. 

Inside  of  the  upper  maxilla. 

Posterior  surface  of  tlie  palate  bone. 

The  nasal  bones. 

The  OS  unguis.     59  Inferior  spongy  bone. 

Right  malar  bone.     61  The  vomer. 

Inferior  maxillary  bone. 

Sutures  of  the  vault  of  the  cranium. 


64  Sutures  of  the  posterior  of  the  cranium. 

65  Diploe  of  the  cranium. 

66  Inside  of  the  base  of  the  cranium. 

67  Outside  of  the  base  of  the  cranium. 

68  The  facial  angle,    69  The  fontanels. 

70  The  OS  hyoides, 

71  Posterior  of  the  scapula. 

72  Axillary  margin  of  the  scapula. 

73  The  clavicle.     74  The  humerus. 
75  The  ulna.    76  The  radius. 

77  The  bones  of  the  carpUs. 

78  The  bones  of  the  hand. 

79  Articulation  of  the  carpal  bones. 

80  Anterior  view  of  the  femur. 

81  Posterior  view  of  the  femur. 

82  The  tibia.     83  The  fibula. 

84  Anterior  view  of  the  patella. 

85  Posterior  view  of  the  patella. 

86  The  OS  ealcis.     87  The  astragalus. 

88  The  naviculare.     89  The  cuboid  bone. 

90  The  three  cuneiform  bones. 

91  Top  of  tlie  foot. 

92  The  sole  of  the  foot.    93  Cells  in  cartilage. 

94  Articular  cartilage  under  the  microscope. 

95  Costal  cartilage  under  the  microscope. 

96  Magnified  section  of  cartilage. 

97  Magnified  view  of  fibro-cartilage. 

98  White  fibrous  tissue. 

99  Yellow  fibrous  tissue. 

100  Ligaments  of  the  jaw. 

101  Internal  view  of  the  same. 

102  Vertical  section  of  the  same. 

103  Anterior  vertebral  ligaments. 

104  Posterior  vertebral  ligaments. 

105  Yellow  ligaments. 

106  Costo-vertebral  ligaments. 

107  Occipito-altoidien  ligaments. 

108  Posterior  view  of  the  same. 

109  Upper  part  of  the  same. 

110  Moderator  ligaments. 

111  Anterior  pelvic  ligaments. 

112  Posterior  pelvic  ligaments. 

113  Sterno-clavicular  ligaments. 

114  Scapulo-humeral  articulation. 

115  External  view  of  elbow  joint. 

116  Internal  view  of  elbow  joint. 

117  Ligaments  of  the  wrist. 

118  Diagram  of  the  carpal  synovial  membrane 

119  Ligtiments  of  the  hip  joint. 

120  Anterior  view  of  the  knee  joint 

121  Posterior  view  of  the  knee  joint. 

122  Section  of  the  rifjht  knee  joint. 

123  Section  of  the  left  knee  joint. 

124  Internal  side  of  tlie  ankle  joint. 

125  External  side  of  the  ankle  joint. 

126  Posterior  view  of  the  ankle  joint. 

127  Ligaments  of  the  sole  of  the  foot. 

128  Vertical  section  of  the  foot. 


PART  II.— DERMOID  AND  MUSCULAR  SYSTEMS. 


129  Muscles  on  the  front  of  the  body  ,/mW  length. 
181  Muscles  on  the  back  of  the  hody,  full  length. 
lao  The  cellular  tissue.    132  Fat  vesicles. 


133  Blood-vessels  of  fat 

134  Cell  membrane  of  fat  vesicles. 

135  Magnified  view  of  the  epidermis. 


Illustrations  to  Smith  and  Horner's  ,Btlas,  continued. 


Fig. 

136  Cellular  tissue  of  the  skin. 

137  Eete  mucosum,  &c.,  of  foot. 

138  Epidermis  and  rete  mucosum. 

139  Cutis  vera,  magnified. 

140  Cutaneous  papillae. 

141  Internal  face  of  cutis  vera. 

142  Integuments  of  foot  under  the  microscope. 

143  Cutaneous  glands.  144  Sudoriferous  organs. 

145  Sebaceous  glands  and  hairs. 

146  Perspiratory  gland  magnified. 

147  A  hair  under  the  microscope. 

148  A  hair  from  the  face  under  the  microscope. 

149  Follicle  of  a  hair.     150  Arteries  of  a  hair. 

151  Skin  of  the  beard  magnified. 

152  External  surface  oF  the  thumb  nail. 

153  Internal  surface  of  the  thumb  uail. 

154  Section  of  nail  of  fore  finger. 

155  Same  highly  magnified. 

156  Development  of  muscular  fibre. 

157  Another  view  of  the  same. 

158  Arrangement  of  fibres  of  muscle. 

159  Discs  of  muscular  fibre. 

160  Muscular  fibre  broken  transversely. 
151  Striped  elementary  fibres  magnified. 

162  Strise  of  fibres  from  the  heart  of  an  ox. 

163  Transverse  section  of  biceps  muscle. 

164  Fibres  of  the  pectoralis  major. 

165  Attachment  of  tendon  to  muscle. 

166  Nerve  terminating  in  muscle. 

167  Superficial  muscles  of  face  and  neck. 

168  Deep-seated  muscles  of  face  and  neck. 

169  Lateral  view  of  the  same. 

,170  Lateral  view  of  superficial  muscles  of  face. 

171  Lateral  view  of  deep-seated  muscles  of  face. 

172  Tensor  tarsi  or  muscle  of  Horner. 

173  Pterygoid  muscles.     174  Muscles  of  neck. 

175  Muscles  of  tongue. 

176  Fascia  profunda  colli. 

177  Superficial  muscles  of  thorax. 


Fig. 

180  Side  view  of  abdominal  muscles. 

181  External  parts  concerned  in  hernia. 

182  Internal  parts  concerned  in  hernia. 

183  Deep-seated  muscles  of  trunk. 

184  Inguinal  and  femoral  rings. 

185  Deep-seated  muscles  of  neck. 

186  Superficial  muscles  of  back. 

187  Posterior  parietes  of  chest  and  abdomen. 

188  Under  side  of  diaphragm. 

189  Second  layer  of  muscles  of  back. 

190  Muscles  of  vertebral  gutter. 

191  Fourtli  layer  of  muscles  of  back. 

192  Muscles  behind  cervical  vertebrae. 

193  Deltoid  muscle. 

194  Anterior  view  of  muscles  of  shoulder. 

195  Posterior  view  of  muscles  of  shoulder. 

196  Another  view  of  the  same. 

197  Fascia  brachialis. 

198  Fascia  of  the  fore-arm. 

199  Muscles  on  the  back  of  the  hand. 

200  Muscles  on  the  front  of  the  arm. 

201  Muscles  on  the  baek  of  the  arm. 

202  Pronators  of  the  fore-arm. 

203  Flexor  muscles  of  fore-arm. 

204  Muscles  in  palm  of  hand. 

205  Peep  flexors  of  the  fingers. 

206  Superficial  extensors. 

207  Deep-seated  extensors. 

208  Rotator  muscles  of  the  thigh. 
909  Muscles  on  the  back  of  the  hip. 

210  Deep  muscles  on  the  front  of  thigh. 

211  Superficial  muscles  on  the  front  of  thigh. 

212  Muscles  on  the  back  of  the  thigh. 

213  Muscles  on  front  of  leg. 

214  Muscles  on  back  of  leg. 

215  Deep-seated  muscles  on  back  of  leg. 

216  Muscles  on  the  sole  of  the  foot. 

217  Another  view  of  the  same. 

218  Deep  muscles  on  front  of  arm. 

219  Deep  muscles  on  back  of  arm. 


178  Deep-seated  muscles  of  thorax. 

179  Froutview  of  abdominal  muscles. 

PART  III.— ORGANS  OF  DIGESTION  AND  GENERATION. 

288  Back  view  of  the  pharynx  and  muscles. 


220  Digestive  organs  in  their  whole  length. 

221  Cavity  of  the  mouth. 

222  Labial  and  buccal  glands. 

223  Teeth  in  the  upper  and  lower  jaws. 

224  Upper  jaw,  with  sockets  for  teeth. 

225  Lower  jaw,  with  sockets  for  teetli. 

226  Under  side  of  the  teeth  in  the  upper  jaw. 

227  Upper  side  of  the  teeth  in  the  lower  jaw. 

228  to  235.  Eight  teeth,  from  the  upper  jaw. 
236  to  243.  Eight  teeth  I'rom  the  lower  jaw. 
244  to  251.  Side  view  of  eight  upper  jaw  teeth, 
252. to  259.  Side  view  of  eight  lower  jaw  teeth. 
260  to  265.  Sections  of  eight  teeth. 

266  to  267.  Enamel  and  structure  of  two  of  the 
teeth. 

268  Bicuspis  tooth  under  the  microscope. 

269  Position  of  enamel  fibres. 

270  Hexagonal  enamel  fibres. 

271  Enamel  fibres  very  highly  magnified, 

272  A  very  highly  magnified  view  of  fig.  268. 

273  Internal  portion  of  the  dental  tubes. 

274  External  portion  of  tlie  dental  tubes. 

275  Section  of  the  crown  of  a  tooth. 

276  Tubes  at  the  root  of  a  bicuspis. 

277  Upper  surface  of  the  tongue. 

278  Under  surface  of  the  tongue. 

279  Periglottis  turned  off  the  tongue. 

280  Muscles  of  the  tongue. 

281  Another  view  of  the  same. 

282  Section  of  the  tongue. 

283  Styloid  muscles,  &c. 

284  Section  of  a  gustatory  papilla. 

285  View  of  anotlier  papilla. 

286  Root  of  the  mouth  and  soft  palate. 

287  Front  view  of  the  pharynx  and  muscles. 


289  Under  side  of  the  soft  palate. 

290  A  lobule  of  the  parotid  gland. 

291  Salivary  glands. 

292  Internal  surface  of  the  pharynx. 

293  External  surface  of  the  pharynx. 

294  Vertical  section  of  the  pharynx. 

295  Muscular  coat  of  the  oesophagus. 

296  Longitudinal  section  of  the  cesophagus. 

297  Parietes  of  the  abdomen. 

298  Reflexions  of  the  peritoneum. 

299  Viscera  of  the  chest  and  abdomen. 

300  Another  view  of  the  same. 

301  The  intestines  in  situ. 
S02  Stomach  and  cesophagus. 

303  Front  view  of  tlie  stomach. 

304  Interior  of  the  stomach. 

305  The  stomach  and  duodenum. 

306  Interior  of  the  duodenum. 

307  Gastric  glands. 

308  Mucous  coat  of  the  stomach. 

309  An  intestinal  villus.     310  Its  vessels. 

311  Glands  of  the  stomach  magnified. 

312  Villus  and  lacteal. 

313  Muscular  coat  of  the  ileum. 

314  Jejunum  distended  and  dried. 

315  Follicles  of  Lieberkuhn 

316  Glands  of  Brunner.     317  Intestinal  glands, 
318  Valvulx  conniventes.     319  lleo-colic  valve. 

320  Viili  and  intestinal  follicles. 

321  Veins  of  the  ileum. 

322  Villi  filled  with  chyle.    323  Peyer's  glands 

324  Villi  of  the  jejunum  under  the  microscope. 

325  Tlie  erecifm.  326  The  mesocolon  and  colon, 
327  Muscular  coat  of  the  colon. 


Ulustrations  to  Smith  and  Horner's  Atlas  continued. 


Fig.     , 

3iJ8  Muscular  fibres  of  the  rectum. 
329  Curvatures  of  the  large  intestiue. 
350  Mucous  follicles  of  the  rectum. 

331  Rectal  pouches. 

332  Follicles  of  the  colon,  highly  magnified. 

333  Folds  and  follicles  of  the  stomach. 

334  Follicles,  &c.  of  the  jejunum. 

335  Villi  and  follicles  of  the  ileum. 

336  Muciparous  glauds  of  tlie  stomach. 

337  Ileum  inverted,  &c. 

338  Glands  of  Peyer  magnified. 

339  Peritoneum  of  the  liver  injected. 

340  Liver  in  situ. 

341  Under  surface  of  the  liver.  342  Hepatic  vein. 

343  Parenchyma  of  the  liver. 

344  Hepatic  blood-vessels.    345  Biliary  ducts. 

346  Angular  lobules  of  the  liver. 

347  Rounded  hepatic  lobules. 

348  Coats  of  the  gall  bladder. 

349  Gall  bladder  injected. 

350  Vena  portarum. 

351  External  face  of  the  spleen, 

352  Internal  face  of  the  spleen. 

353  Splenic  vein. 

354  Pancreas  &c.,  injected.  355  Urinary  organs. 

356  Right  kidney  and  capsule. 

357  Left  kidney  and  capsule, 

358  Kidney  under  the  microscope. 

359  The  ureter.     360  Section  of  right  kidney. 

361  Section  of  the  left  kidney. 

362  Pyramids  of  Malpighi, 

363  Lobes  of  the  kidney. 

364  Renal  arteries,  &c.,  injected. 

365  Section  of  the  kidney  highly  magnified. 

366  Copora  Malpighiana.     367  Same  magnified. 
368  Tubuli  uriniferi.     369  Corpora  Wolffiana. 

370  The  bladder  and  urethra,  full  length. 

371  Muscular  coat  of  the  bladder. 


Fig. 

373  Sphincter  apparatus  of  the  bladder. 

374  Prostate  and  vesiculee  seminales. 

375  Side  view  of  the  pelvic  viscera. 

376  The  glans  penis  injected. 

377  The  penis  distended  and  dried. 

378  Section  of  the  same. 

379  Vertical  section  of  the  male  pelvis.  &c 

380  Septum  pectiniforme. 

381  Arteries  of  the  penis. 

382  Vertical  section  of  the  urethra. 

383  Vesiculse  seminales  injected. 

384  Muscles  of  the  male  perineum. 

385  Interior  of  the  pelvis,  seen  from  above. 

386  Testis  in  the  fffitus. 

387  Diagram  of  the  descent  of  the  testis. 

388  Tunica  vaginalis  testis. 

389  Transverse  section  of  the  testis. 

390  Relative  position  of  the  prostate. 

391  Vas  deferens. 

392  Vertical  section  of  the  bladder. 

393  The  testicle  injected  with  mercury. 

394  Another  view. 

595  Minute  structure  of  the  testis. 

396  Female  generative  organs. 

397  Another  view  of  the  same. 

398  External  organs  in  the  foetus. 

399  Muscles  of  the  female  perineum. 

400  Side  view  of  the  female  pelvis,  &c. 

401  Relative  position  of  the  female  organs." 

402  Section  of  the  uterus,  &c, 

403  Fallopian  tubes,  ovaries,  &c. 

404  Front  view  of  the  mammary  gland. 

405  The  same  after  removal  of  the  skin. 

406  Side  view  of  the  breast. 

407  Origin  of  lactiferous  ducts. 

408  Lactiferous  tubes  during  lactation. 

409  Minute  termination  of  a  tube. 

410  Ducts  injected  ;  after  Sir  Astley  Cooper. 


372  Another  view  of  the  same. 

PART  IV.— ORGANS  OF  RESPIRATION  AND  CIRCULATION. 


411  Front  view  of  the  thyroid  cartilage. 

412  Side  view  of  the  thyroid  cartilage. 

413  Posterior  of  the  arytenoid  cartilage. 

414  Anterior  of  the  arytenoid  cartilage. 

415  Epiglottis  cartilage.    416  Cricoid  cartilage. 

417  Ligaments  of  the  larynx, 

418  Side  view  of  the  same. 

419  The  thyroid  gland. 

420  Internal  surface  of  the  larynx. 

421  Crico-thyroid  muscles. 

422  Crico-arytenoid  muscles. 

423  Articulations  of  the  larynx. 

424  Vertical  section  of  the  larynx. 

425  The  vocal  ligaments.     426  Thymus  gland. 

427  Front  view  of  the  lungs. 

428  Back  view  of  the  lungs. 

429  The  trachea  and  bronchia. 

430  Lungs,  heart,  kc. 

431  First  ai)\)earance  of  the  blood-vessels. 

432  Capillary  vessels  magnified. 

433  Another  view  of  the  same. 

434  Blood  globules. 

435  Another  view  of  the  same. 

436  The  mediastiua. 

437  Parericiiyma  of  the  lung. 

438  The  heart  and  pericardium. 

439  Anterior  view  of  the  heart. 

440  Posterior  view  of  the  heart. 

441  Anterior  view  of  its  muscular  structure. 

442  Posterior  view  of  the  same. 

443  Interior  of  the  right  ventricle. 

444  Interior  of  the  left  ventricle. 

445  Mitral  valve,  the  size  of  life. 

446  The  auriculo-ventricular  valves, 

447  Section  of  the  ventricles. 

448  The  arteries  from  the  arch  of  tlie  aorta. 

449  The  arteries  of  the  neck,  the  size  of  life. 


450  The  external  carotid  artery. 

451  A  front  view  of  arteries  of  head  and  neck. 

452  The  internal  maxillary  artery. 

453  Vertebral  and  carotid  arteries  with  the  aorta. 

454  Axillary  and  brachial  arteries. 

455  The  brachial  artery. 

456  Its  division  at  the  elbow, 

457  One  of  the  anomalies  of  the  brachial  artery. 

458  Radial  and  ulnar  arteries. 

459  Another  view  of  the  same. 

460  The  arcus  sublimis  and  profundus, 

461  The  aorta  in  its  entire  length. 

462  Arteries  of  the  stomach  and  liver. 

463  Superior  mesenteric  artery. 

464  Inferior  mesenteric  artery. 

465  Abdominal  aorta. 

466  Primitive  iliac  and  femoral  arteries. 

467  Perineal  arteries  of  the  male. 

468  Position  of  the  arteries  in  the  inguinal  canal. 

469  Internal  iliac  artery.    470  P'emoral  artery. 

471  Gluteal  and  ischiatic  arteries, 

472  Branches  of  the  ischiatic  artery. 

473  Popliteal  artery. 

474  Anterior  tibial  artery. 

475  Posterior  tibial  artery, 

476  Supeificial  aiteries  on  the  top  of  the  foot, 

477  Deep-seated  arteries  on  the  lop  of  the  foot. 

478  Posterior  tibial  artery  at  the  ankle. 

479  The  plantar  arteries. 

480  Arteries  and  veins  of  the  face  and  »eck. 

481  Gieat  vessels  from  the  heart. 

482  External  jugular  vein. 

483  Lateral  view  of  the  vertebral  sinuses. 
4S4  Posterior  view  of  the  vertebral  sinuses. 

485  Anterior  view  of  the  vertebral  sinuses, 

486  Superficial  veins  of  the  arm. 

487  The  same  at  the  elbow. 


Illustrations  to  Smith  and  Horner's  Atlas  continued. 


Fig. 

488  The  veins  of  the  hand. 

489  The  great  veins  of  the  trunk. 

490  Positions  of  the  arteries  and  veins  of  the  trunk. 

491  The  venw  cavse.    492  The  vena  portarum. 

493  Deep  veins  of  the  back  of  the  leg. 

494  Positions  of  the  veins  to  the  arteries  in  the 

arm.    493  Superficial  veins  of  the  thigh. 

496  Saphena  vein. 

497  Superficial  veins  of  the  leg. 

498  Lymphatics  of  the  upper  extremity. 


Fig. 

499  The  lymphatics  and  glands  of  the  axilla. 

500  The  femoral  and  aortic  lymphatics. 

501  The  lymphatics  of  the  small  intestines. 

502  The  thoracic  duct. 

503  The  lymphatics  of  the  groin. 

504  Superficial  lymphatics  of  the  Oiigh. 

505  Lymphatics  of  the  jejunum. 

506  Deep  lymphatics  of  the  thigh. 

507  Superficial  lymphatics  of  the  leg, 

508  Deep  lymphatics  of  the  leg. 


PART  v.— THE  NERVOUS  SYSTEM  AND  SENSES. 


509  Dura  mater  cerebri  and  spinalis.  57& 

510  Anterior  view  of  brain  and  spinal  marrow.  574 

511  Anterior  view  of  the  spinal  marrow,  &c.  575 

512  Lateral  view  of  the  spinal  marrow,  &c.  |t  576 

513  Posterior  view  of  the  spinal  marrow,  &c.  ^7T 

514  Decussation  of  Mitischelli.  578 

515  Origins  of  the  spinal  nerves.  579 

516  Anterior  view  of  spinal  marrow  and  nerves.    580 

517  Posterior  view  of  spinal  marrow  and  nerves.    581 

518  Anterior  spinal  commissure.  582 

519  Posterior  spinal  commissure.  583 

520  Transverse  section  of  the  spinal  marrow.  584 

521  Dura  mater  and  sinuses.  585 

522  Sinuses  laid  open.  586 

523  Sinuses  at  the  base  of  the  cranium.  587 

524  Pons  Varolii,  cerebellum,  &c.  588 

525  Superior  face  of  the  cerebellum.  589 

526  Inferior  face  of  the  cerebellum.  590 

527  Another  view  of  the  cerebellum.  591 

528  View  of  the  arbor  vitie,  &c.  593 

529  Posterior  view  of  the  medulla  oblongata.  594 

530  A  vertical  section  of  the  cerebellum.  595 

531  Another  section  of  the  cerebellum.  596 

532  Convolutions  of  the  cerebrum.  597 

533  The  cerebrum  entire.  598 

534  A  section  of  its  base.  599 

535  The  corpus  callosum  entire.  600 

536  Diverging  fibres  of  the  cerebrum,  &c.  601 

537  Vertical  section  of  the  head.  602 

538  Section  of  the  corpus  callosum.  603 

539  Longitudinal  section  of  the  brain.  604 

540  View  of  a  dissection  by  Gall.  605 

541  The  commissures  of  the  brain.  606 

542  Lateral  ventricles.  607 

543  Corpora  striata-fornix,  &c.  608 

544  Fifth  ventricle  and  lyra.  609 

545  Anotherjview  of  the  lateral  ventricles.  610 

546  Another' view  of  the  ventricles.  611 

547  Origins  of  the  4th  and  5th  pairs  of  nerves.  612 

548  The  circle  of  Willis.  613 

549  A  side  view  of  the  nose.  614 

550  The  nasal  cartilages.  615 

551  Bones  and  cartilages  of  the  nose.  616 

552  Oval  cartilages,  kc,  617 

553  Schneiderian  membrane.  618 

554  External  parietes  of  the  left  nostril.  619 

555  Arteries  of  the  nose.  6"20 

556  Pituitary  membrane  injected.  621 

557  Posterior  nares.     558  Front  view  of  the  eye.    622 

559  Side  view  of  the  eye.  623 

560  Posterior  view  of  tlie  eyelids,  &c.  624 

561  Glandulse  palpebrarum.  625 

562  Lachrymal  canals.  626 

563  Muscles  of  the  eyeball.  627 

564  Side  view  of  the  eyeball.  628 

565  Longitudinal  section  of  the  eyeball.  629 

566  Horizontal  section  of  the  eyeball.  630 

567  Anterior  view  of  a  transverse  section.  631 

568  Posterior  view  of  a  transverse  section.  632 

569  Choroid  coat  injected.  633 

570  Veins  of  the  choroid  coat.  634 

571  The  iris.    572  Thejretina  and  lens. 


External  view  of  the  same. 

Vessels  in  the  conjunctiva. 

Retina,  injected  and  magnified. 

L'is,  highly  magnified. 

Vitreous  humour  and  lens. 

Crystalline  adult  lens. 

Lens  of  the  fcEtus,  magnified. 

Side  view  of  the  lens. 

Membrana  pupillaris. 

Another  view  of  the  same. 

Posterior  view  of  the  same. 

A  view  of  the  left  ear. 

Its  sebaceous  follicles. 

Cartilages  of  the  ear. 

The  same  with  its  muscles. 

The  cranial  side  of  the  ear. 

Meatus  auditorius  externus,  &c. 

Labyrinth  and  bones  of  the  ear. 

Full  view  of  the  malleus.    592  The  incus. 

Another  view  of  the  malleus. 

A  front  view  of  the  stapes. 

Magnified  view  of  the  stapes. 

Magnified  view  of  the  incus. 

Cellular  structure  of  the  malleus. 

Magnified  view  of  the  labyrinth. 

Natural  size  of  the  labyrinth. 

Labyrinth  laid  open  and  magnified. 

Labyrinth,  natural  size. 

Labyrinth  of  a  fffitus. 

Another  view  of  the  same. 

Nerves  of  the  labyrinth. 

A  view  of  the  vestibule,  &c. 

Its  soft  parts,  &c. 

An  ampulla  and  nerve. 

Plan  of  the  cochlea. 

Lamina  spiralis,  &;c. 

The  auditory  nerve. 

Nerve  on  the  lamina  spiralis. 

Arrangement  of  the  coublea. 

Veins  of  the  cochlea,  higldy  magnified. 

Opening  of  the  Eustacliian  tube  in  the  throat. 

Portio  mollis  of  the  seventh  pair  of  nerves, 

Tiie  olfactory  nerves. 

The  optic  and  seven  other  pairs  of  nerves. 

Third,  fourth  and  sixth  pairs  of  nerves. 

Distribution  of  the  fifth  pair. 

The  facial  nerve. 

The  hypo-glossal  nerves. 

A  plan  of  the  eighth  pair  of  nerves. 

The  distribution  of  the  eighth  pair. 

The  great  sympathetic  nerve. 

The  brachial  plexus. 

Nerves  of  the  front  of  the  arm. 

Nerves  of  the  back  of  the  arm. 

Lumbar  and  istliiatic  nerves. 

Posterior  branches  to  the  hip,  &c. 

Anterior  crural  nerve. 

Anterior  tibial  nerve. 

Brandies  of  the  pojiliteal  nerve. 

Posterior  tibial  nerve  on  the  leg. 

Posterior  tibial  nerve  on  the  foot. 


NOW  READY. 

TAYLOR'S   MEDICAL    JURISPRUDENCE. 


MEDICAL  JUKISPKUDENCE, 

By  ALFRED  S.  TAYLOR, 

Lecturer  on  Medical  Jurisprudence  and  Chemistry  at  Guy's  Hoopilal,  &c. 

With  numerous  Notes  and  Additions,  and  references  to  American 
practice  and  law. 
By  R.  E.  GRIFFITH,  M.  D. 
In  One  Volume,  8vo. 
Contents. — poisoning — wounds — infanticide — drowning — hanging — strak- 

GULATION — SUFFOCATION LIGHTNING COLD STARVATION RAPE PREGNANCY 

DELIVERY BIRTH INHERITANCE LEGITIMACY — INSANITY,  &e.  &C. 

'■Tl'.e  promise  of  tlie  first  parts  was  so  full,  and  the  ability  displayed  was  so  unquestionable,  that  all  ■who  fell 
jealous  of  the  honour  of  our  national  medical  literature  hailed  with  delight  the  appearance  of  a  comprehensive 
and  original  work  of  English  growth,  on  one  of  the  most  important  and  difficult  departments  of  our  science. 
Every where,  indeed,  we  find  evidences  of  extensive  reading  and  laborious  research;  the  copious  literature, 
both  of  France  and  Germany,  on  the  subject  of  Medical  Jurisprudence,  is  laid  under  frequent  ctmtribution, 
and  we  have  the  pleasure  of  meeting  with  the  accumulated  stores  of  science  and  experieiice  on  this  branch 
of  knowledge,  it  may  be  said  of  the  whole  world,  condensed  and  made  accessible  in  this  adniirable  volume. 
It  is,  in  fact,  not  only  the  fullest  and  most  satisfactory  book  we  have  ever  consulted  on  the  subject  of  which  h 
treats,  but  it  is  also  one  of  the  most  masterly  books  we  have  ever  perused.  So  much  precise  individual  kno'v?- 
ledgo,  under  guidance  of  judgrr>ent  and  critical  powers  of  so  high  an  order,  as  meet  us  in  every  page  of  Mr, 
Taylor's  work,  we  have  rarely  encountered." — London  Med.  Gazelle. 

'■We  recommend  Mr.  Taylor's  work  as  the  ablest,  most  comprehensive,  aad,  above  all,  the  most  practically 
useful  book  which  exists  on  the  subject  of  legal  medicine.  Any  man  of  sound  judgment,  who  has  mastered 
the  contents  of  Taylor's  'Medical  Jurisprudence,'  may  go  into  a  court  of  law  witlj  the  most  perfect  coafidence 
of  being  able  to  acquit  himself  creditably." — Medico- Ckirurgical  Review. 

"The  work  of  Mr.  Taylor  may  be  regarded  as  a  full  systematic  treatise  on  the  subject  of  Medical  Jurispru- 
dence. It  certainly  presents  a  very  excellent  view,  which  may  be  named  both  full  aiul  condensed,  of  the 
present  slate  of  knowledge  on  Medical  Jurisprudence.  The  author  lias  illustrated  many  of  Che  doubtful  points 
of  the  science  by  good  and  interesting  cases.  He  has,  in  general,  shown  much  vudgment  in  the  examinatioa 
of  the  difficult  and  ambiguous  cases;  but  the  whole  treatise  is  so  ably  prepared  that  we  have  no  hesitation  ia 
recommending  it  as  a  very  useful  guide  to  the  student." — Edinhtirgh  Med.  and  Surg.  JonmeU. 

"The  most  elaborate  and  complete  work  that  has  yet  appeared.  It  contains  an  immense  qnaatity  of  cases, 
lately  tried,  which  entitles  it  to  be  considered  now  what  Beck  was  in  its  day." — Dublin  Meddeal  Journal. 

"Medical  Jurisprudence  ought  to  be  a  prominent  branch  of  the  studies  of  every  lawyer:  but  what  books 
shall  they  read?  We  have  seen  none  so  calculated  lo  serve  the  purpose  of  a  text-book  as  this  manual.  Mr. 
Taylor  possesses  the  happy  art  of  expressing  himself  on  a  scientific  topic  in  intelligible  laaiguage.  Its  size 
£ts  it  to  be  a  circuit  companion.." — Law  Times. 

ALSO,  NOW  READY, 


THE    PRINCIPLES    OF    SURGERY. 

By  JAMES  MILLER,  F.  R.  S.  E.,  F.  R.  C.  S.  E., 

Professor  of  Surgery  in  the  University  nf  Edinburgh,  &e. 

In  One  neat  8vo.  Volume, 
To  match  in  size  with  Fergusson^s  Operative  Surgery. 

''No  one  ean  peruse  this  work  without  the  conviction  that  he  has  been  addressed  by  an  accomplished  sur- 
geon, endowed  with  iio  mean  literary  skill  or  doubtful  good  sense,,  and  who  knows  how  to  grace  or  illumine 
his  subjects  with  th«  later  lights  of  our  rapidly  advancing  physiology.  The  book  deserves  a  strong  recoHj- 
mendation,  and  must  secure  itself  a  general  perusal.'" — Medical  Times. 


BARTLETT'S  PHILOSOPHY  OF  MEDICINE. 


AN  ESSAY  ON 
THE  PHILOSOPHY  OF  MEDICAL  SCIENCE. 

IN  TWO  PARTS. 

"  I  trust  that  I  have  got  hold  of  my  pitcher  by  the  right  handle-." — John  Joachim  JBecehef. 

By  ELISIIA  BARTLETT,  M.  D., 

Professor  of  the  Theory  awl  Practice  of  Medicincivihe  University  of  Maryland. 

In  One  neat  Octavo  Volume. 

"We  have  not  room  m  the  present  number  of  our  journal,  ibr  such  h  notice  of  this  philosophical  aiwi  elega-ni 
woric.  as  its  merits  justly  demand.  It  i.s  evidently  destined  to  create  quite  a  sensation  ia  the  medical  world ; 
and  we  shall  Ihere&jre  give  an  extended  analysis  of  its  coiucnls.  nceompanicd  by  some  comments  incur  Jan- 
uary number.  Ia  the  mean  time,  we  advise  all  our  readers  to  purchase  and  carefully  read  it.'"— iV.  Y.  Jo^imal  of 
Medicine. 


(p=°  Gentlemen  who  receive  this  Catalogue  would  much  oblige  the 
PuhTishers,  if,  after  reading  it,  they  would  hand  it,  or  the  following  eight 
pages,  to  tlieir  friends. 
12 


LEA    AND    BLANCHARD, 
PHILADELPHIA, 

ARE  PREPARING  FOR  PUBLICATION,  AND  WILL  SHORTLY  ISSUE, 

THE   NARRATIVE  OF  THE 


DURING    THE  YEARS 

1838,    1839,    1840,    1841,    and    1842. 

Br  CHARLES  WILKES,  U.  S.  N., 

COMMANDER  OF  THE  EXPEDITION,  ETC.,  ETC. 

In  Five  Octavo  Yolumes,  of  about  2500  Pages ;  with  over  SCO  Cuts, 

and  Maps. 

As  the  history  of  tie  only  Expedition  yet  commissioned  by  our  Government  to  explore  foreign  countries,  this 
work  must  present  features  of  unusual  interest  to  every  American.  Much  curiosity  has  been  excited  respecting 
this  enterprise,  from  the  length  of  time  during  which  it  was  in  preparation,  and  from  the  various  conflicting  re- 
ports which  were  circulated  during  its  protracted  absence. 

The  Squadron — six  vessels— sailed  from  Norfolk  in  August,  1838,  and  after  making  important  observations  on 
tiie  voyage,  via.  JVIadeira,  arrived  at  Rio,  when  their  investigations  were  successfully  prosecmed.  Sailing 
thence  for  Cape  Horn,  they  examined  the  commercial  capabilities  of  Rio  Negro.  Arriving  at  Cape  Horn,  two 
«fthe  vessels  were  dispatched  to  investigate  Palmer's  Land,  and  other  Antarctic  Regions;  whence,  after  encoun- 
tering great  danger,  they  returned  safely,  and  sailed  with  the  whole  Squadron  for  Valparaiso  and  Callao.  After 
making  important  observations  on  the  West  Coast  of  South  America,  regarding  the  commerce,  political  history, 
&c.,  of  that  portion  of  America,  they  sailed  for  Sydney,  cruising  among  the  numerous  groups  of  islands  of  the 
Pacific  Archipelago,  where  the  results  were  peculiarly  important,  as  connected  with  the  commerce  and  Whale 
Fishery  of  our  coimtry,  as  well  as  the  aid  they  were  able  to  bring  to  the  various  missionary  establishments  en- 
gaged in  the  introduction  of  Christianity  and  civilization.  After  remaining  some  time  at  Sydney,  pursuing  im- 
portant investigations,  they  sailed  for  the  Antarctic  Regions,  leaving  behind  them  tlie  corps  of  Naturalists  to 
explore  that  singular  country,  the  observations  on  which  will  be  found  of  great  interest.  The  Squadron  then 
proceeding  South,  made  the  brilliant  discovery  of  the  Axtarctic  Continent,  on  the  19th  January,  1840,  in  16(P 
east  longitude,  along  which  they  coasted,  in  a  westerly  direction,  to  95°  east,  a  distance  of  15C0  miles.  On  the 
return  of  the  vessels,  tliey  touched  at  New  Zealand,  when  the  Naturalists  were  again  taken  on  board.  They 
next  proceeded  to  the  Friendly  Islands  of  Cook,  the  Feejee  Group,  and  reached  the  Sandwich  Islands  late  in  the 
fall,  which  precluded  them  from  going  to  the  North- West  Coast  that  season.  The  Paumotu,  Samoan,  and  King's 
Mills  group  of  islands  were  visited,  and  a  particular  examination  made  of  the  Island  of  Hawaii,  its  interesting 
craters  and  vplcanic  eruptions.  In  the  spring,  the  Squadron  proceeded  to  the  Oregon  Territory,  now  exciting  so 
much  interest  in  a  political  point  of  view;  it  was  thoroughly  examined  in  regard  to  its  conunercial  and  agricul- 
tural prospects,  See.  Here  the  Peacock  was  lost  on  the  dangerous  bar  of  the  Columbia  river.  After  the  Oregon, 
Upper  California  was  examined.  The  Expedition  now  returned  to  the  Sandwich  Islands,  and  thence  sailed  for 
Manilla  and  Singapore,  touching  at  the  Philippine  Islands,  and  passing  through  the  Sooloo  Sea,  the  channels  of 
which  being  correctly  ascertained,  will  greatly  benefit  the  important  navigation  to  China. 

Touching  at  the  Cape  of  Good  Hope  and  Rio,  this  important  and  successful  E.xploring  Expedition  finally,  on 
die  10th  of  June,  1842,  arrived  at  New  York,  after  an  absence  of  three  years  and  ten  months. 

During  the  whole  Voyage,  every  opportunity  was  taken  to  procure  information,  investigate  unknown  or  little 
frequented  parts  of  those  seas  now  reached  by  our  commerce,  and  thoroughly  to  institute  scientific  investigations 
of  all  kinds.  To  illustrate  these,  a  vast  number  of  drawings  and  maps  have  been  executed;  but  the  chief  objects 
ia  view  were  of  a  practical  nature.  Numerous  regulations  have  been  made  with  the  rulers  of  various  islands, 
to  secure  the  safety  of  our  commerce,  now  daily  increasing  in  those  seas.  In  short,  every  thing  has  been  done 
which  lay  in  the  power  of  officers  or  men  to  make  the  Expedition  redound  to  the  interest  and  honour  of  the 
Gauatry;  aad  ia  the  volumes  to  be  issued  will  be  found  its  history  and  embodiment. 

13 


E  AS  T'S    RE  PORTS. 


LEA  AND  BLANCHARD,  PHILADELPHIA, 

HAVE  IN  PRESS,  AND  WILL  SHORTLY  PUBLISH, 

REPORTS    OF    CASES 

ADJUDGED  AND  DETERMINED 


COURT  OF  KING'S  BENCH; 

WITH 

TABLES  OF  THE  NAMES  OF  THE  CASES.  AND  PRINCIPAL  MATTERS. 
By  EDWARD  HYDE  EAST,  Esq., 

OF  THE  INNER  TEMPLE,  BARRISTER  AT  LAW, 

EDITED,    WITH    NOTES    AND    REFERENCES. 
By  G.  M.  WHARTON,  ESQ., 


OF  THE  PHILADELPHIA  BAR. 


In  this  new  and  improved  Edition,  the  sixteen  original  will  be  com- 
prised in  eight  large  Royal  Octavo  volumes,  printed  with  beautiful  Long 
Primer  type,  on  paper  manufactured  expressly  for  the  purpose,  and  every 
care  will  be  taken,  in  their  passage  through  the  press,  to  insure  perfect 
accuracy. 

The  price  of  the  work  handsomely  bound  in  Law  Sheep,  to  those  who 
subscribe  before  the  day  of  publication,  will  be  only  Twenty-Five  Dollars, 
being  a  great  reduction  from  Seventy-Two  Dollars,  the  pubhshing  price 
of  the  former  edition.  The  publishers  trust  that  this  moderate  charge  will 
insure  a  hberal  subscription. 

Twenty-seven  years  have  elapsed  since  the  publication  of  the  last  Ameri- 
can Edition  of  East's  Reports  by  Mr.  Day,  and  the  work  has  become  ex- 
ceedingly scarce.  This  is  the  more  to  be  regretted,  as  the  great  value  of 
these  Reports,  arising  from  the  variety  and  importance  of  the  subjects  con- 
sidered in  them,  and  the  fulness  of  the  decisions  on  the  subjects  of  Mer- 
cantile Law,  renders  them  absolutely  necessary  to  the  American  Lawyer. 
The  judgments  of  Lord  Kenyon  and  Lord  Ellenborough,  on  all  Practical 
and  commercial  points,  are  of  the  highest  authority,  and  the  volumes 
which  contain  them  should  form  part  of  every  well-selected  law  library. 

These  considerations  have  induced  the  publishers  to  prepare  a  new  edi- 
tion, in  which  nothing  should  be  omitted.  The  editor,  G.  M.  Wharton, 
Esq.,  proposes  to  add  a  brief  annotation  of  the  leading  cases  in  the  Reports, 
with  references  to  the  more  important  decisions  upon  similar  points  in  the 
principal  commercial  States  of  the  Union,  while  the  Notes  of  Mr.  Day  will 
be  retained,  and,  though  the  whole  work  will  be  compressed  into  eight 
volumes,  the  original  Cases,  as  reported,  will  be  preserved  entire.  At  the 
head  of  each  Report,  a  reference  will  be  had  to  the  paging  of  the  English 
Ediiion,  directly  under  the  name  of  the  case,  and  the  original  indexes  will 
be  incorporated  together  at  the  end  of  each  volume  of  this  Edition. 

Subscriptions  received  by  the  publishers.  Lea  &  Blanchard,  Philadel- 
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14 


LIBRARY  OF  STANDARD  LITERATURE. 

Lea  &  Blanchard  are  publisliing,  under  the  general  title  of  The  Library  of 
Standard  Literature,  a  number  of  valuable  works  on  History,  Biography,  &c.  &c., 
which  merit  a  permanent  place  in  every  library.  Among  them  are  contained  the 
following: 

NIEBUHR'S  HISTORY  OF  ROME. 

Complete  in  Two  large  8vo.  Volumes,  or  Five  Parts,  Paper,  at  $1  each. 

THE    HISTORY    OF    ROME, 

BY  B.  G.   NIEBUHR. 

TRANSLATED  BT 

JULIUS  CHARLES  HARE,  M.A.  |  WILLIAM  SMITH,  Ph.  D.  and 

CONNOP  THIRLWALL,  M.A.  |  LEONARD  SCHMITZ,  Ph.  D. 

WITH    A    MAP. 

The  last  three  parts  of  this  valuable  work  have  never  before  been  published  in  this  country, 
having  only  lately  been  printed  in  Germnny,  and  transliited  in  England.  They  complete  the 
history,  bringing  it  down  to  the  time  of  Constantine. 

"  Here  we  close  our  remarks  upon  tliis  memorable  work ;  a  work  which,  of  all  that  have  appeared  in  our  age, 
is  the  best  fitted  to  excite  men  of  learning;  to  intellectual  activity ;  from  which  the  most  accomplished  scholar  may- 
gather  fresh  storesof  knowledge,  to  which  the  most  experienced  politician  may  resort  for  theoretical  and  practical 
instruction,  and  which  no  person  can  read  as  it  ought  to  be  read,  without  feeling  the  better  and  more  generous  sen- 
timents of  his  common  human  nature  enlivened  and  strengthened.'" — Edinburgh  Review,  Jan.,  1S33. 

"The  world  has  now  in  Niebuhr  an  imperishable  model." — Edinburgh  Review,  Jan.,  1844. 

"  At  length  the  American  reader  can  have  easy  access  to  the  unrivaled  Histor)'  of  Rome,  by  Niebuhr.  a  work 
which  combines  deep  critical  research  with  full  political  disquisition  and  comparison." — Colonization  Herald. 

"  The  Historj-  of  Niebuhr  has  throvv^n  new  light  on  our  knowledge  of  Roman  affairs,  to  a  degree  of  which  those 
unacquainted  with  it  can  scarcely  form  an  idea." — Quarterly  Review. 

"It  is  since  I  saw  you  that  I  have  been  devouring  with  the  most  intense  admirationthethird  volume  of  Niebuhr. 
The  clearness  and  comprehensiveness  of  all  his  military  details  is  a  new  feature  in  that  wonderful  mind,  and 
how  inimitably  beautiful  is  that  brief  account  of  Terni  V—Dr.  Arnold  (Life,  vol.  2). 

This  edition  will  comprise  in  the  fourth  and  fifth  volumes,  tlie  Lectures  of  Professor  Niebuhr,  on  the  latter  part 
of  Roman  History,  so  long  lost  to  the  world.    Concerning  them  the  Eclectic  Review  says : 

"  It  is  an  unexpected  surprise  and  pleasure  to  the  admirers  of  Niebuhr — that  is  to  all  earnest  students  of  ancient 
historj' — to  recover,  as  if  from  the  grave,  the  lectures  before  us." 

And  the  London  Athenaeum : 

"  We  have  dwelt  at  sufficient  length  on  these  volumes  to  show  how  highly  we  appreciate  the  benefit  which 
the  editor  has  conferred  on  liistorical  literature  by  their  publication." 


HISTORY  OF  THE  REFORMATION 

U  IN     GERMANY. 

BY   PROFESSOR  LEOPOLD   RANKE. 

Parts  First  and  Second.    Price  -25  Cents  each. 

TRANSLATED  FROM  THE  SECOND  EDITION, 

BY    SARAH    AUSTEN. 

To  be  completed  in  about  Five  Parts,  each  Part  containing  One  Volume  of  the  London  Edition. 


RANKE'S  HISTORY  OF  THE  POPES, 

THEIR  CHURCH  AND  STATE, 

DURING  THE  SIXTEENTH  AND  SEVENTEENTH  CENTURIES. 

A  NEW  TRANSLATION, 

BY    WALTER    K.     KELLY. 

In  One  neat  Octavo  Volume,  extra  cloth;  or  Two  Parts,  Paper,  at  One  Dollar  each, 

15 


LIBRARY  OF  STANDARD  LITERATURE  CONTINUED. 

RANKE'S  HISTORY  OF  THE  OTTOMAN  AND  SPANISH  EMPIRES. 

TRANSLATED  FROM  THE  GERMAN 

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In  One  Fart,  Paper,  at  Seventy-five  Cents. 
This  book  completes  the  uniform  series  of  Professor  RankS's  Historical  Works.    When  bound 
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and  the  purchase  and  sale.     Together  with  a  General  History  of  the  Horse;  a  disser- 
tation ou  the  American  Trotting  Horse,  how  trained  and  jockeyed, 
an  account  of  his  remarkable  performances,  and 
an  Essay  on  the  Ass  and  the  Mule, 
BY  J.  S.  SKINNER, 
Assistant  Post-Master  General  and  Editor  of  the  Turf  Register. 
In  One  VoluiTie,  oi.tavo. 

YOUATT  AND  GLATER'S  OATTLE  ANB  SHEEP-BQGTOR/ 


EVERY  MAN  HIS 


NOW   READY, 

OWN  CATTLE 


AND  SHEEP-DOCTOR: 


CONTAINING 


THE  CAUSES,  SYMPTOMS,  AND  TREATMENT  OF  AIL  THE  DISEASES  INCIDENT  TO 

QXEXH,  SHBEF,  AI^B  Sl^IS^S. 

Br  FRANCIS  CLATER. 

EDITED,  REVISED,  AND  ALMOST  REWRITTEN, 

By  WILLIAM  YOUATT,  Author  of  "The  Horse,"  &c. 

Together  with  numo'ous  Additions,  by  the  American  Editor,  J.  S.  Skinner. 

AMONG  WHICH  ARE 

AN  ESSAY  ON  THE  USE  OP  OXE\,  WITH  MODES  OF  BREAKING,  FEEDING,  GRAZING,  ETC. 

AND  A  TREATISE  ON  THE  GROWTH.  IMPROVEMENT  AND  BREEDING  OF  SHEEP, 

AND  THE  SOILS  ADAPTED  TO  THEIR  RAISING. 

With  numerous  Cuts  and  Illustrations.     In  one  volume,  12mo. 

Price  Fifty  Cents,  in  Cloth. 

JUST   PUBLISHED, 

M  ARSTONj 

OR,  THE  MEMOIRS  OF  A  STATESMAN, 

In  two  parts,  at  -25  Cents  each. 


DICKENS' 
THE  CHIMES, 


NEW    WORK. 
A  GOBLIN  ST 


OF  SOME  BELLS  THAT  RUNG  AN  OLD  YEAR  OUT   AND  A  NEW-YEAR  IN. 
A  CHEAP  EDITION,  IN  PAPER  COVERS, 
AND  A  FINE  EDITION  WITH  PLATES. 
(^  See  the  List  for  a  new  edition  of  Campbell's  Poetical  Works,  by  Wash.  Irving  and  Lord 
Jeffreys.  19 


WATSON'S  PRACTICE   OF  MEDICINE, 


L.  &  B.  HAVE  LATELY  PUBLISHED 

LECTURES 

ON  THE  PRINCIPLES  AND  PRACTICE  OE  PHYSIC. 

DELIVERED  AT  KING'S  COLLEGE,  LONDON. 
Br  THOMAS  WATSON,  M.  D., 

Fellow  of  the  Royal  College  of  Physicians,  Physician  to  the  Middlesex  Hospital,  ^c.  ^c. 

In  One  large  Octavo  Volume,  of  over  7-ii?ie  hundred  unusually  large 
pages,  strongly  bound  in  leather,  containing  Ninety  Lectures.  Offered  to 
the  public  at  a  very  low  price. 

This  volume,  although  so  short  a  time  before  the  medical  public  of  this  country,  has  met  with  almost  unprece- 
dented approbation  from  all  classes  of  the  profession,  teachers,  practitioners  and  students,  in  every  section  of  the 
countrj-;  and  has  been  favourably  noticed  by  all  the  medical  journals. 

The  publishers  submit  the  following  notice  of  its  approval  from  the  Professor  of  the  University  of  Pennsylva- 
nia, and  from  some  of  the  journals,  foreign  and  domestic,  which  have  borne  testimony  to  its  excellence. 

Phila.,  Sept.  21th,  1844. 
Watson's  Practice  of  Physic,  in  my  opinion,  is  among  the  most  compre- 
hensive works  on  the  subject  extant,  replete  with  curious  and  important 
matter,  and  written  with  great  perspicuity  and  felicity  of  manner.  As  cal- 
culated to  do  much  good,  I  cordially  recommend  it  to  that  portion  of  the 
profession  in  this  country  who  may  be  influenced  by  my  judgment. 

N.  Chapman,  M.D., 

Professor  of  the  Practice  and  Tlieory  of  Medicine  in  the  University  of  Pennsylvania. 

"  We  know  of  no  other  work  better  calculated  for  application  of  therapeutics  to  diseases,  v/e  are  free  to 

being  placed  in  the  hands  of  the  student,  and  for  a  text  say  has  not  appeared  for  very  many  years.    The  lec- 

book,  and  as  such  we  are  sure  it  will  be  very  extea-  turer  proceeds  through  the  whole  classification  of  human 

sively  adopted.    On  every  important  point,  the  author  ills,  a  capite  ad  calcem,  showing  at  every  step  an  exten- 

seems  to  have  posted  up  his  knowledge  to  the  day." —  sive  knowledge  of  his  subject,  with  the  ability  of  com- 

Ameri<;an  Medical  Journal.  municating  his  precise  ideas,  in  a  style  remarkable  for 

"In  the  Lectures  of  Dr.  Watson,  now  republished  its  clearness  and  simplicity." — N.   Y.  Journal  of  Medi- 

here  in  a  large  and  closely  printed  volume,  in  small  ct?i«  and  Surgery. 

type,  of  nearly  a  thousand  pages,  we  have  a  body  of  "The  style  is  correct  and  pleasing,  and  the  matter 

doctrine  and  practice  of  medicine  well  calculated,  by  worth  the  attention  of  aM  practitioners,  young  and  old." 

its  intrinsic  soundness  and  correctness  of  style,  to  in-  — Western  Laticet. 

struct  the  student  and  younger  practitioner,  and  improve  "We  are  free  to  slate  that  a  careful  examination  of 

members  of  the  profession  of  every  age." — Bulletin  of  this  volume  has  satisfied  us  that  it  merits  all  the  commen- 

Medical  Science.  dalion  bestowed  on  it  in  this  coitntry  and  at  home.    It  is 

"  We  know  not.  indeed,  of  any  work  of  the  same  a  work  adapted  to  the  wants  of  young  practitioners, 

size  that  contains  a  greater  amount  of  useful  and  in-  combining,  as  it  does,  sound  principles  and  substantial 

teresting  matter.    We  are  satisfied,  indeed,  that  no  phy-  practice.   It  is  not  too  much  to  say,  that  it  is  a  represent- 

sician,  well  read  and  observing  as  he  may  be,  can  rise  ativeof  tlie  actual  slate  of  medicine  as  taught  and  prac- 

from  its  perusal  williout  having  added  largely  to  liis  tised  by  the  most  eminent  physicians  of  the  present  day, 

stock  of  valuable  information." — Medical  Examiner.  and  as  such  we  would  advise  every  one  about  embark- 

"  We  regard  these  lectures  as  the  best  exposition  of  ing  in  the  practice  of  physic  to  provide  himself  with  a 
their  subjects  of  any  we  remember  to  have  read.     The  copy  of  it." — Western  Jour)ial  of  Med.  and  Surifery. 
author  is  assuredly  master  of  his  art.    His  has  been  a  "  The  medical  literature  of  this  country  has  been  en- 
life  of  observation  and  study,  and  in  this  work  he  has  riched  by  a  work  of  standard  excellence,  which  we  can 
given  us  tlie  matured  results  of  these  mental  efforts." —  proudly  hold  up  to  our  brethren  of  other  countries  as  a  • 
New  Orleans  Medical  Journal.  representative  of  the  natural  stale  of  British  medicine, 

"Openthis  huge,  well-furnished  volume  where  we  as  professed  and  practised  by  our  most  enlightened  phy- 

may,  the  eye  immediately  rests  on  something  that  car-  sicians.    And,  for  our  own  parts,  we  are  not  only  wil- 

ries  value  on  its  front.    We  are  impressed  at  once  with  ling  that  our  characters  as  scientific  physicians  and 

the  strength  and  depth  of  the  lecturer's  views.    Ilegains  skilful  practitioners  may  be  deduced  from  the  doctrines 

on  our  admiration  in  proportion  to  the  extent  of  our  ac-  contained  in  this  book,  but  we  hesitate  not  to  declare 

quaintance  with  his  profound   researches.    Whoever  our  belief,  that  for  sound,  trustworthy  principles,  and 

DMvns  this  book,  will  have  an  acknowledged  treasure  if  substantial,  good  practice,  it  cannot  be  paralleled  by  any 

ihecombincd  wisdomof  the  highestauthorities  is  appre-  similar  production  in  any  other  country.  *  *  *  *    AVo 

elated." — Boston  Meil.  and  Surg.  Journal.  would  advise  no  one  to  set  himself  down  in  practice,  un- 

"One  of  die  most  practically  useful  books  that  ever  provided  with  a  copy." — British  and  Foreign  Medical 

was  presented  to  the  .student— mdced,  a  more  admirable  lieview, 
gummo-ry  of  general  and  epeciai  pathology,  and  of  ilie 


Lea  &  Blanchard  publish  and  have  for  sale  the  following  valuable  Medical 
Works  by  Professor  Robley  Dunglison. 


WITH     UPWARDS    OE    THREE    HUNDRED    ILLUSTRATIONS, 

By  robley  dunglison,  M.  D., 

PROFESSOR  OF  THE  INSTITUTES  OF  MEDICINE,  &C.    IN  JEFFERSON  MEDICAL  COLLEGE,  PHILADA.; 

ATTENDING  PHYSICIAN  AND  LECTURER  ON  CLINICAL  MEDICINE  AT  THE  PHILADA.  MEDICAL  HOSPITAL; 

SECRETARY  TO  THE  AMERICAN  PHILOSOPHICAL  SOCIETY,  &C.  &C. 

FIFTH  ESITION,  GREATLY  MQBIFIED  AND  IMPROVED. 

TN  TWO   VOZiUIi^llS,   or    130^   IaJLB.&^   OCTAVO    FikCrES. 

In.  presenting  this  new  and  much  improved  edition  of  Professor  Dunglison's  standard  work  on  Physiologj',  the 
Publishers  beg  to  state,  tliat  "although  only  a  short  time  has  elapsed  since  the  publication  of  the  fourth  edition 
of  this  work,  the  labours  of  Physiologists  have  been  so  numerous,  diversified,  and  important,  as  to  demand  ma- 
terial modifications  and  additions  in  the  present  edition,  and  that  no  little  time  and  industry-  have  been  bestowed 
by  the  author  to  introduce  these,  and  to  digest  the  var  ous  materials  contained  in  the  exprofesso  treatises,  as  well 
as  the  various  Journals  of  this  country  and  of  Europe. 

■■To  this  edition  nearly  ninety  wood-cuts  have  been  added  to  elucidate  either  topics  that  had  been  already  treat- 
ed of  in  the  previous  editions,  or  such  as  are  new  in  this ;  most  of  the  old  cuts  have  been  retouched,  and  many 
replaced  by  oihers  that  are  superior.  Altogetlter,  the  author  has  endeavoured  to  make  the  work  a  just  and  im- 
partial record  of  Physiolog'cal  science,  and  to  render  it  worthy  a  continuance  of  that  favour  which  has  been  so 
liberally  exiended  to  it."  The  size  of  the  volumes  has  been  materially  increased,  by  the  addition  of  over  eighty 
pages,  and  the  illustrations  are  far  superior  to  those  of  any  former  edition. 


(3R  A  TREATISE  ON 

SPECIAL  PATHOLOGY  AND  THERAPEUTICS. 
BY  ROBLEY  DUNGLISON,  M.  D., 

CONTAINING 

THE  DISEASES  OF  THE  ALIMENTARY  CANAL,  THE  DISEASES  OF  THE 
CIRCULATORY  APPAKATUtr!,  DISEASES  OF  THE  GLANDULAR  ORGANS, 

DISEASES  OF  THE  ORGANS  OF  THE  SENSES,  DISEASES  OF  THE 

KESPIRATORY  ORGANS,  DISEASES  OF  THE  GLANDIFORM  GANGfJONS, 

DISEASES  OF  THE  NERVOUS  SYSTEM,  DISEASES  OF  THE  ORGANS  OF 

REPRODUCTION,  DISEASES  INVOLVING  VARIOUS  ORGANS,  &c.  &c. 

In  Two  Volumes,  Octavo. 

Tliis  work  has  been  introduced  as  a  text-book  in  many  of  the  Medical  colleges,  and  the  general  favour  with 
which  it  has  lieen  received,  is  a  guarantee  of  its  value  to  the  practitioner  and  student. 

"In  the  volumes  before  us.  Dr.  Dunglison  has  proved  that  his  acquaintance  with  the  present  facts  and  doc- 
trines, wheresoever  originating,  is  most  extensive  and  intimate,  and  the  judgment,  skill,  and  impartiality  with 
which  the  materials  of  the  work  have  been  collected,  weighed,  arranged,  and  exposed,  are  strikingly  manitested 
in  every  chapter.  Great  care  is  ever^-where  taken  to  indicate  the  source  of  intbrmation,  and  under  the  head  of 
treatment,  formute  of  the  most  appropriate  remedies  are  everywhere  introduced.  In  conclusion,  we  congratu- 
late the  students  and  junior  practitioners  of  America,  on  possessing  in  the  present  volumes,  a  work  of  standard 
merit,  to  which  they  may  confidently  relisr  in  their  doubts  and  difficulties." — British  and  Foreign  Medical  Review 
for  July,  1842. 

"  Since  the  foregoing  observations  were  written,  we  have  received  a  second  edition  of  Dtmglison's  work,  a 
sufficient  indication  ot  the  high  charactef  it  has  already  attained  in  America,  and  justly  attained." — British  and 
Foreign  Medical  Rei-iewfor  October,  1S44. 

"  We  hail  the  appearance  of  this  work,  which  has  just  been  issued  from  the  prolific  press  of  Messrs.  Lea  & 
Blanchard,  of  Philadelphia,  with  no  ordinary  degree  of  pleasure.  Comprised  in  two  large  and  closely  printed 
volumes,  it  exhibits  a  more  full,  accurate,  and  comprehensive  d'gest  of  the  existing  state  of  medicine  than  any 
other  treatise  with  wliich  we  are  acqua'nted  in  the  English  language.  It  discusses  many  topics — some  of  them 
of  ffreat  practical  importance,  which  are  entirely  omitted  in  the  writings  of  Eberle,  Dewees,  Hosack,  Graves, 
Stokes,  Mcintosh,  and  Gregory;  and  it  cannot  fail,  therefore,  to  be  of  great  value,  not  only  to  the  student,  but  to 
the  practitioner,  as  it  affords  him  ready  access  to  information  of  vv-hich  he  stands  in  daily  need  in  the  exercise  of 
his  profession.  It  has  been  the  desire  of  the  author,  well  known  as  one  of  the  most  abundant  writers  of  the  age, 
to  render  his  work  strictly  practical ;  and  to  this  end  he  has  lieen  induced,  whenever  opportunity  oflisred,  to 
incorporate  the  results  of  his  own  experience  with  tliat  of  his  scientific  brethren  in  America  and  Europe.  To 
the  former,  ample  justice  seems  to  have  been  done  throughout.  We  believe  this  constitutes  the  seventli  work 
which  Professor  Dunglison  has  published  within  the  last  fen  years ;  and,  when  we  reflect  upon  the  large  amount 
of  labour  and  reflection  which  must  have  been  necessary  in  iheir  preparation,  it  is  amazing  how  he  could  have 
accomplished  so  much  in  so  short  a  time," — LouisKilU  Journal. 


HEW    REMEDIES, 

PHARMACEUTICALLY    AND    THERAPEUTICALLY    CONSIDERED. 

By  robley  dunglison,  M.D., 
In  One  Volume,  Octavo— over  600  pages,  the  Fourth  Edition. 


21 


PROFESSOR  DUNGLISON'S  WORKS. 


A  NEW  EDITION  OF 

THE  STAHDARL  MEDICAL   DIGJTIOirAE,?. 
A    DICTIONARY    OF    MEDICAL    SCIENCE: 

CONTAINING 
A    CONCISE   ACCOUNT   OF   THE   VARIOUS   SUBJECTS   AND   TERMS,  WITH 
THE    FRENCH   AND    OTHER   SYNONYMES,   NOTICES    OF    CLIMATE    AND 
OF  CELEBRATED   MINERAL  WATERS,  FORMULA    FOR  VARIOUS  OFFICl- 
NAL  AND  EMPIRICAL  PREPARATIONS,  ETC. 

Fourtli  Sditioii,  Extensively  Modified  and  Improved. 

By  ROBLEY  DUNGLISON,  M.  D., 

In  One  Volume,  Royal  Octavo. 

"Tlie  present  undertaking  was  suggested  by  the  frequent  complaints  made  by  the  author's  pupils,  that  they 
■were  unable  to  meet  with  information  on  numerous  topics  of  professional  inquiry — especially  of  recent  intro- 
duction— in  the  medical  dictionaries  accessible  to  them. 

"  It  may,  indeed,  be  correctly  affirmed,  that  we  have  no  dictionary  of  medical  subjects  and  terms  which  can 
be  looked  upon  as  adapted  to  the  state  of  the  science.  In  proof  of  this  the  author  need  but  to  remark,  that  the 
present  edition  will  he  found  to  contain  at  least  two  thousand  subjects  and  terms  not  embraced  in  the  last  edition, 
and  to  have  experienced  immerous  modifications. 

"The  author's  object  has  not  been  to  make  the  work  a  mere  lexicon  or  dictionary  of  terms,  but  to  afford,  under 
each,  a  condensed  view  of  its  various  medical  relations,  and  thus  to  render  the  work  an  epitome  of  the  existing 
condition  of  medical  science. 

'•  To  execute  such  a  work  requires  great  erudition,  unwearied  industry,  and  extensive  research;  and  we  know 
no  one  who  could  bring  to  the  task  higher  qualifications  of  this  description  than  Professor  Dunglison." — Ameri- 
can MedicalJournal. 


GENERAL  THEMPEUTICS  AND  MATERIA  MEDICA, 

ADAPTED    FOR    A    MEDICAL    TEXT-BOOK. 

Br  ROBLEY  DUNGLISON,  M.D., 

In  Two  Volumes,  Octavo. 

"The  subject  of  Materia  Medica  has  been  handled  by  our  author  with  more  than  usual  judgment.  The  greater 
part  of  treatises  on  that  subject  are,  in  effect,  expositions  of  the  natural  and  chemical  history  of  the  substances 
used  in  medicine,  with  very  brief  notices  at  all  of  the  indications  they  are  capable  of  fulfilling,  and  the  general 
principles  of  Therapeutics.  Dr.  Dunglison,  very  wisely,  in  our  opinion,  has  reversed  all  this,  and  given  his 
principal  attention  to  the  articles  of  the  Materia  Medica  as,  medicines.  .  ...  .  In  conclusion,  we  strongly  recom- 
mend these  volumes  to  our  readers.  No  medical  student  on  either  side  of  the  Atlantic  should  be  without  them." 
— Forbes^  British  and  Foreign,  Medical  Revievj. 

LATELY  PUBLISHED, 

DUHG-LISOH  OH  HUMAH  HIE-ALTH. 


HUMAN    HEALTH; 

OR,  THE  INFLUENCE  OF  ATMOSPHERE  AND  LOCALITY,  CHANGE  OF  AIR 

AND  CLIMATE,  SEASONS,  FOOD,  CLOTHING,  BATHING  AND 

MINERAL  SPRINGS,  EXERCISE.  SLEEP,  CORPOREAL 

AND  INTELLECTUAL  PURSUITS,  &c.  «&c.  ON 

HEALTHY  MAN: 

CONSTITUTING  ^ 

ELEMENTS    OF    HYGIENE. 
By  ROBLEY  DUNGLISON,  M.  D., 

A  NEW  EDITION  WITH  MANY  MODIFICATIONS  AND  ADDITIONS. 

In  One  Volume,  8vo. 
"We  have  just  received  the  new  edition  of  this  learned  work  on  the  'Elements  of  Hygiene.'    Dr.  Dunglison 
is  one  of  the  most  industrious  and  voluminous  authors  of  the  day.     Jlow  he  finds  linie  lo  amass  and  arrange  the 
immense  amount  of  matter  contained  in  his  various  works,  is  almost  above  the  comprehension  of  men  possessing 
but  ordinary  talents  and  industry.    Sucli  labour  deserves  immortality." — St.  Lnuis  Med.  and  Surg.  Journal. 

A  NEW  EDITION  OF 

THE   MEDICAL   STUDENT; 
OR,  AIDS  TO  THE  STUDY  OF  MEDICINE. 

A  REVISED  AND  MODIFIED  EDITION. 

BY  ROBLP]Y  DUNGLISON,  M.D., 

In  One  neat  12mo.  Volume. 

"In  effect,  the  author'.s  aim  is  to  teach  the  t);ro  what  he  ought  to,  and  how  he  may  study  to  the  best  advantage 
both  before  and  after  he  has  attained  the  dignity^  of  a  inedical  diploma;  and  while  he  gives  liim  much  good  advice 
in  an  agreeable  manner  and  enforced  by  happyil lustrations,  he  endeavours  to  simplify  his  labours  by  presenting 
him  with  'a  glossary  of  tlie  prefixes,  suffixes  and  r.'ulicals  of  many  of  the  terms  legitimately  comjjounded,' of 
medical  technology,  a  vocabulary  of  terms  used  in  prescribing  and  other  useful  information," — American  Medical 
Journal. 

2Z 


THE  CYCLOP/EOIA  OF  PRACTICAL  MEDICINE, 

TO     BE    READY    IN     MARCH. 

Forming  Four  magnificent  super-royal  Octavo  Volumes  of  about  3200  unusually 
large  double-columned  pages,  printed  on  beautiful  white  paper,  with  a  new  and 
clear  type,  done  up  in  strong  sheep  binding,  or  neat  extra  cloth;  or,  in  Twenty- 
four  Parts,  at  Fifty  Cents  each. 

LEA  &  BLANCHARD  ARE  NOW  ISSUING 

THE  CYCLOPAEDIA  OF  PRACTICAL  MEDICINE: 

COMPRISING 

TREATISES  ON  THE 

NATURE  AND  TREATMENT  OE  DISEASES, 

MATERIA    MEDICA    AND    THERAPEUTICS, 

DISEASES  OF  WOMEN  AND  CHILDREN, 

MEDICAL  JURISPRUDENCE,  &c.  &c. 

EDITED  BY 

JOHN  FORBES,  M.  D.,  F.  R.  S., 
ALEXANDER  TWEEDIE,  M.  D.,  F.  R.  S., 

AND 

JOHN  CONOLLY,  M.  D. 

REVISED,   WITH    ADDITIONS, 

Br  ROBLEY  DUNGLISON,  M.  D. 

This  work  is  printed  on  good  paper  with  a  new  and  clear  type,  and  forms 

FOUR  VERY  LARGE  SUPER-ROYAL  OCTAVO  VOLUMES, 

with  over  three  thousand  unusually  large  pages,  in  double  columns. 


This  work  has  now  been  in  the  course  of  publication  for  about  ten  months, 
and  is  nearly  completed,  twenty-two  numbers  having  been  issued,  and  the  whole 
will  be  completed  early  in  March. 

The  parts  already  published  contain  the  following  valuable  articles  by  distin- 
guished authors: 

CONTENTS  OF  PART  I.  CONTENTS  OF  PART  III. 


Abdomen,  Exploration  of  the,  Dr.  Forbes. 

Abortion,  Dr.  h'-e. 

Abscess,  Internal.  Dr.  Tweedie. 

Abstinence,  Dr.  Marshall  Hal!. 

Achor.  Dr.  Todd. 

Acne.  Dr.  Todd. 

Acrodynia,  Dr.  Dunglison. 

Acupuncture.  Dr.  Elliotson. 

Agre,  Dr.  Roget. 

Air,  Change  of.  Sir  James  Clarke. 

Alopecia,  Dr.  Todd. 

Alteratives,  Dr.  Conolly. 

Amauro.sis,  Dr.  Jacob. 

Amenorrhcea.  Dr.  Locock. 

Ancpmia.  Dr.  IVIarshall  1  iaii. 

Anasarca,  Dr.  Darwall. 

Angina  Pectoris.  Dr.  Forbes. 

Anodynes.  Dr.  "Whiting. 

Anthelmintics.  Dr.  A.  T.  Thomson. 

Anthracion.  Dr.  Dunglison. 

Antiphlogistic  Regimen.  Dr.  Barlo'w. 

Antispasmodics,  Dr.  A.  T.  Thomson. 

Aorta,  Aneurism  of.  Dr.  Hope. 

CONTENTS  OF  PART  11. 

Apoplexy,  Cerebral,  Dr.  Clntlerbuck. 

'•  l^ulmonary,  Dr.  Towiisend. 

Arteritis.  Dr.  I  lope. 
Ascites,  Dr.  Darwall. 
Artisans,  Diseases  of.  Dr.  Darwall. 
Asphyxia,  Dr.  Roget. 

"  of  the  iVew  Bom,  Dr.  Dunglison. 

Asthma,  Dr.  Forlies. 
Astringents,  Dr.  A.  T.  Thomson. 
Atrophy,  Dr.  Townsend. 
Auscultation,  Dr.  Forbes. 
Barbiers,  Dr.  Scott. 
Baihing,  Dr.  Forbes. 


Bathing  (continued),  Dr.  Forbes. 

Beriberi,  Dr.  Scott. 

Blood,  Determination  of,  Dr.  Barlow. 

Morbid  States  of.  Dr.  Marshall  Hall. 
Blood-letting,  Dr.  Marshall  Hall. 
Brain,  Inflammation  of  the. 

Meningitis.  Dr.  Quain. 

Cerebntis.  Dr.  Adair  Crawford. 
Bronchial  Glands,  Diseases  of  the.  Dr.  Dunglison. 
Bronchitis,  Acute  and  Chronic,  Dr.  Williams. 

"        Summer,  Dr.  Dunglison. 
Bronchocele,  Dr.  And.  Crawford. 
Bullae.  Dr.  Todd. 
Cachexia,  Dr.  Dunglison. 
Calculi,  Dr.  T.  Thomson. 
Calculous  Diseases,  Dr.  Cumin. 
Catalepsy.  Dr.  Joy. 
Catarrh,  Dr.  Williams. 
Cathartics.  Dr.  A.  T.  Thomson. 
Chest.  Exploration  of  the.  Dr.  Forbes. 
Chicken  I'o.x,  Dr.  Gregory. 
Chlorosis,  Dr.  Marshall  Hall. 
Cholera,  Common  and  Epidemic,  Dr.  Brown. 

CONTENTS  OF  PART  IV. 

Cholera,  Epidemic,  (continued.)  Dr.  Brown. 

"        Infantum,  Dr.  Dunglison, 
Chorea.  Dr.  And.  Crawlbrd. 
Cirrhosis  of  the  Iiung.  Dr.  Dunglison. 
Climate.  Dr.  Clark. 
Cold.  Dr.  Whiting. 
Colic,  Drs.  AVhiling  and  Tweedie. 
Colica  Piclonum,  Dr.  Whiting. 
Colon,  Torpor  of  the.  Dr.  Dunglison. 
Coma,  Dr.  Adair  Crawford. 
Combustion.  Spontaneous.  Dr.  Apjoha. 
Congestion  of  Blood,  Dr.  Barlow. 
Constipatioiij  Drs.  Hastings  and  Slreeren. 

23 


Contents  nf  Cyclopcedia  of  Practical  Medicine. 


Cpntasrion,  Dr.  Brown. 
Convalescence.  Dr.  Tweedie. 
Convulsions,  Dr.  Adair  Crawford. 

"  Infantile,  Dr.  Locock. 

"  Puerperal,  Dr.Locock. 

Coryza.  Dr.  Williams. 
Counter  Irritation,  Dr.  Williams. 
Croup,  Dr.  Cheyne. 

CONTENTS  OF  PART  V. 

Cxo'ap.[<^ontimted,)  Dr.  Cheyne. 
C\-anosis.  Dr.  Crampton. 
Cystitis,  Dr.  Cumin. 
Dead,  Persons  found,  Dr.  Beatty. 
Delirium,  Dr.  Prilchard. 

■■        Tremens,  Drs.  Carter  and  Dunglison. 
Dengue,  Dr.  Dunglison, 
Dentition.  Disorders  of.  Dr.  Joy. 
Derivation.  Dr.  Stokes. 
Diabetes,  Dr.  Bardsley. 
Diagnosis,  Dr.  Marshall  Hall. 
Diaphoretics,  Dr.  A.  T.  Thomson. 
DiarrhcEa,  Drs.  Crampton  and  Forbes. 

"         Adipous,  Dr.  Dunglison. 
Dietetics,  Dr.  Paris. 

CONTENTS  OF  PART  VI. 

Dietetics,  (continw6rf,)Dr.  Paris. 
Disease,  Dr.  Conolly. 
Disinfectants,  Dr.  Dunglison. 
Disinfection,  Dr.  Brown. 
Diuretics,  Dr.  A.  T.  Thomson. 
Dropsy,  Dr.  Darwall. 
Dysenterj',  Dr.  Brown. 
Dysmenorrhcea.  Dr.  Locock. 
D>-sphagia,  Dr.  Stokes. 
D>-spncEa,  Dr.  AVilliams. 
Ihsuria,  Dr.  Cumin. 
Ecth)ina,  Dr.  Todd. 
Eczema,  Dr.  .Toy. 
Education,  Physical.  Dr.  Barlow. 
Electricity,  Dr.  Apjohn. 
Elephantiasis,  Dr.  ,Ioy. 
Emetics,  Dr.  A.  T.  Thomson. 
Emmenagogues,  Dr.  A.  T.  Thomson. 

CONTENTS  OF  PART  VII. 

Emphysema,  Dr.  R.  Townsend. 

"  of  the  Lungs.  Dr.  R.  Townsend. 

Empyema,  Dr.  R.  Townsend. 
Endemic  diseases.  Dr.  Hancock. 
Enteritis.  Drs.  Stokes  and  Dunglison. 
Ephelis,  Dr,  Todd. 
Epidemics,  Dr,  Hancock. 
Epilepsy,  Dr.  Cheyne. 
Epistaxis,  Dr.  Kerr. 
Ereihismus  Mercurialis,  Dr.  Burder. 
Erysipelas,  Dr.  Tweedie. 
Erythema,  Dr.  Joy. 
Eutrophic,  Dr.  Dunglison. 
Exanthemata,  Dr.  Tweedie. 
Expectorants,  Dr.  A.  T.  Thomson. 
PJxpectoration,  Dr.  Williams. 
Fayus,  Dr.  A.  T.  Thomson, 
Feigned  diseases,  Drs.  Scott,  Forbes  and  Marshall. 

CONTENTS  OF  PART  VIII. 

Feigned  diseases,  (continued,)  Drs.  Scott,  Forbes  and 

Marshall. 
Fever,  general  doctrine  of,  Dr.  Tweedie. 

"        Continued,  and  its  modifications,  Dr.  Tweedie. 

"        Typhus,  Dr.  Tweedie. 

"        Epidemic  Gastric,  Dr.  Cheyne. 

"        Intermittent,  Dr.  Brown. 

"        Remittent,  Dr.  Brown. 

"        Malignant  Remitent,  Dr.  Dunglison. 

"        Infantile.  Dr.  .Toy. 

"       Hectic,  Dr.  Brown. 

"        Puerperal,  Dr.  Lee. 

"        Yellow,  Dr.  GiUkresL 

CONTENTS  OF  PART  IX. 

Fever,  Yellow,  (eoniimier),)  Dr.  Gillkrest. 
Fungus  H.-nmatodes,  Dr.  Kerr. 
Galvanism,  Drs.  Apjohn  and  Dunglison. 
Gastritis,  Dr.  Stokes. 
Gastrodynia,  Dr.  Harlow. 
Gastro-Enterilis.  Dr.  Stokes. 
CJlanders,  Dr.  Dunglison. 
Glossitis,  Dr.  Kerr. 

24 


Glottis,  Spasm  of  the,  Dr.  Joy. 
Gout,  Dr.  Barlow. 
Hcematemesis,  Dr.  Goldie. 
Haemoptysis,  Dr.  Lavir. 
Headache,  Dr.  Burder. 
Heart,  Diseases  of  the.  Dr.  Hope. 

"       Dilatation  of  the,  Dr.  Hope. 

"       Displacement  of  the,  Dr.  Townsend. 

"       Fatty  and  greasy  degeneration  of  the.  Dr.  Hope. 

"       Hypertrophy  of  the,  Dr.  Hope. 

CONTENTS  OF  PART  X. 

Heart,  Hypertrophy  o( \he,(continved.)  Dr.  Hope. 

"       Malformations  of  the,  Dr.  "Williams. 

"      Polypus  of  the.  Dr.  Dunglison. 
•   "      Rupttire  of  the,  Dr.  Townsend, 

"      Diseases  of  the  Valves  of  the.  Dr.  Hope. 
Haemorrhage,  Dr.  AVatson. 
Hasmorvhoids,  Dr.  Burne. 
Hereditary  transmission  of  disease,  Dr.  Brown. 
Herpes,  Dr,  A,  T,  Thomson. 
Hiccup,  Dr,  Ash. 
Hooping  Cough,  Dr,  Johnson. 
Hydatids,  Dr.  Kerr. 
Hydrocephalus,  Dr.  Joy. 
Hydropericardium.  Dr.  Darwall. 
Hydrophobia,  Dr.  Bardsley. 

CONTENTS  OF  PART  XI. 

Hydrophobia,  (continved,)  Dr.  Bardsley. 
Hydrothorax,  Dr.  Darwall. 
Hypercesthesia,  Dr.  Dunglison. 
Hypertrophy,  Dr.  Townsend. 
Hypochondriasis,  Dr.  Pritchard. 
Hysteria,  Dr.  Conolly, 
Ichthyosis,  Dr.  Thomson. 
Identity,  Dr.  Montgomery. 
Impetigo,  Dr.  A.  T.  Thomson. 
Impotence,  Dr.  Beatly. 
Incubus,  Dr.  Williams. 
Indigestion,  Dr.  Todd, 

CONTENTS  OF  PART  XH. 

Indigestion,  {continued.)  Dr.  Todd. 

Induration,  Dr.  Carswell.  ^ 

Infanticide,  Dr.  Arrowsmith. 

Infect'on,  Dr.  Brown. 

Inflammation,  Drs.  Adair  Crawford  and  Tweedie. 

CONTENTS  OF  PART  XIH. 

Influenza,  Dr,  Hancock. 
Insanity,  Dr.  Pritchard. 
Intussusception.  Dr.  Dunglison. 
Irritation,  Dr.  Williams. 
Jaundice,  Dr.  Burder. 

"         of  the  Infant,  Dr.  Dunglison. 
Kidneys,  diseases  of.  Dr.  Carter, 
liactation.  Dr.  Locock. 
Laryngitis,  Dr,  Cheyne, 

'•  Chronic,  Dr,  Dunglison. 

I^atent  diseases.  Dr.  Christisoh. 
Lepra,  Dr.  1  (oughton. 
Lcucorrhcea,  Dr.  Locock. 
I,ichen.  Dr.  Iloughton. 
Liver.  Diseases  of  the.  Dr.  Stokes, 

CONTENTS  OF  PART  XIV. 

Liver,  Diseases  of  the,  {continued.)  Dr.  Venables. 

"       Inflammation  of  the.  Dr.  Stokes. 
Malaria  and  Mia.fflia.  Dr.  Brown. 
Medicine,  History  of.  Dr.  Bostock. 

"  American,  before  the  Revolution,  Dr.  J.  B. 

Beck. 
"  Slate  of  in  the  19th  century.  Dr.  Alison. 

"  Practical,  Principles  of,  Dr.  Conolly. 


CONTENTS  OF  PART  XV. 

Medicine,  Practical,  Principles  of.  Dr.  Conolly. 

Mekcna,  Dr,  Goldie, 

Melanosis,  Dr.  Carswell, 

Menorrhagia,  Dr.  T-ooock. 

Menstruation,  Patliology  of,  Dr.  Locock. 

Miliaria,  Dr,  Tweedie, 

Milk  Sickness,  Dr.  Dunglison. 

Mind,  Soundness  and  Unsoundness  of,  Drs.  Pritchard 

and  Dunglison. 
Molluflcum,  Dr.  Diaiglison. 
Mortification,  Dr.  Carswell. 
Narcotics,  Dr.  A.  T.  Thomson. 


Contents  of  Cyclop sedia  of  Practical  Medicine. 


Nauseants,  Dr.  Dunglison. 
Nephralgia  and  Nephritis,  Dr.  Carter. 
Neuralgia,  Dr.  EUiotsoii. 
Noli-Me-Tangere  or  Lupus,  Dr.  Houghion. 
Nyctalopia,  Dr.  Grant. 

CONTEiVTS  OF  TART  XVI. 

Nyctalopia,  (coutinufd.)  Dr.  GrauL 

Qbesiiy,  Dr.  ^^•lllu.!las. 

(Edema.  Dr.  Daruali. 

Ophthalmia.  Drs  .IucoIjs  and  Dunglisoru 

Olalgia  and  Otitis,  Dr.  Burne. 

Ovaria,  Diseases  ol'llie,  Dr.  I..ee. 

Palpitation,  Drs.  Hope  and  Dunp'iison. 

Pancreas,  diseases  ol'tlie,  Dr.  Carter. 

Paralysis.  Dr.  Todd. 

Parotitis,  Dr.  Kerr. 

Parturients.  Dr.  Dunglison. 

Pellagra,  Dr.  Kerr. 

Pempliigus,  Dr.  Corrigan. 

Perforation  of  the  liollow  Viscera.  Dr.  CarswcU. 

Pericarditis,  Dr.  Hope. 

Peritonitis,  Drs.  Me  Adam  and  Stokes. 

CONTENTS  OF  PART  XVII. 

Peritonitis,  (cnntinued,)  Dr.  Stokes. 
PhlegTOasia  Dolens,  Dr,  Lee. 
Pityriasis,  Dr.  Cumin. 
Pls^ue,  Dr.  Brown. 
Pletliora,  Dr.  Barlow. 
Pleurisy.  Dr.  Law. 
Plica  Polonica,  Dr.  Corrigan. 
Pneumonia.  Dr.  Williams. 
Pneumothorax,  Dr.  i  iougiiton. 
Porrigo,  Dr.  A.  T.  Thoirison. 

CONTENTS  OF  PART  XVIIL 

Porrigo,  {conliinierl.)  Dr.  A.  T.  Thomson. 

Pregnancy  and  Delivery,  signs  of,  Dr.  Monigomery. 

Prognosis,  Dr.  Ash. 

Prurigo,  Dr.  A.  T.  Thomson. 

Pseiido-IVIorbid  Appearances,  Dr.  Todd. 

Psoriasis,  Dr.  Cumin. 

Ptyalism,  Dr.  Dunglison. 

Puerperal  Diseases,  Dr.  Marshall  Hall. 

Pulse,  Dr.  Boslock. 

Purpura,' Dr.  Goldie. 

Pus,  Dr.  Tweedie. 

Pyrosis,  Dr.  Kerr. 

Rape,  Dr.  Beatly. 

CONTENTS  OF  PART  XIX. 
■  Refrigerants,  Dr.  A.  T.  Thomson. 


Rheumatism,  Drs.  Barlow  and  Dunglison. 

Rickets,  Dr.  Cumin. 

Roseola,  Dr.  Tweedie. 

Rubeola,  Dr.  Montgomery. 

Rupia,  Dr.  Corrigan. 

Scabies,  Dr.  Houghion. 

Scarlatina.  Dr.  Tweedie. 

Scirrhus,  Dr.  Carswell. 

Scorbutus.  Dr.  Kerr. 

Scrofula,  Dr.  Cumin. 

CONTENTS  OF  PART  XX. 

Scrofula,  (contimied,)  Dr.  Cumin. 

Sedatives.  Drs.  A.  T.  Thomson  and  Dunglison. 

Sex.  Doiibtlul,  Dr.  Beatly. 

Small  Pox,  Dr.  Gregory. 

Softening  of  Organs,  Dr.  Carswell. 

Somnambulism  and  An  mal  Magnetism,  Dr.  Pritchard. 

Spcrmatorrhosa,  Dr.  Dunglison. 

Spinal  Marrow,  Diseases  of  the.  Dr.  Todd. 

Spleen,  Diseases  of  the,  Drs.  Bigsby  and  Dunglison. 

Statistics,  Medical,  Drs.  Hawkins  and  DungUsorL 

Stethoscope.  Dr.  Williams. 

Stimulants.  Dr.  A.  T.  Thomson. 

Stoinacli,  Organic  Diseases  of,  Dr.  Houghton. 

CONTENTS  OF  PART  XXI. 

Stomach,  Organic  Diseases  of,  (continued,)  Dr.  Hough- 
ton and  Dunglison. 
Stomatitis.  Dr.  Dunglison. 
Strophulus,  Dr.  Dunglison. 

Succession  of  Inheritance,  Legitimacy,  Dr.  Montgomery. 
Suppuration,  Dr.  Todd. 
Survivorship,  Dr.  Beatty. 
Sycosis,  Dr.  Cumin. 
Symtomatology,  Dr.  Marshall  Hall. 
Syncope,  Dr.  Ash. 
Tabes  Jlcsenterica,  Dr.  Joy. 
Temperament,  Dr.  Pritchard. 
Tetanies.  Dr.  Dunglison. 
Tetanus.  Dr.  Symonds. 
Throat,  Diseases  of  the.  Dr.  Tweedie. 
Tissue  Adventitious, 
Tonics,  Dr.  A.  T.  Thomson. 

CONTENTS  OF  PART  XXII. 

Tonics,  (contimied.)  Dr.  A.  T.  Thomson.  ■ 

Toodiache,  Dr.  Dimglison. 

Toxicology,  Di-s.  Apjohn  and  Dunglison. 

Transformations,  Dr.  Duesbury. 

Transfusion,  Dr.  Kay. 

Tubercle,  Dr.  Carswell. 

Tubercular  Phthisis,  Dr.  Clark. 


'■  We  rejoice  that  this  work  is  to  be  placed  within  the  reach  of  the  profession  in  this  country,  it  being  unques- 
tionably one  of  very  great  value  to  the  practitioner.  This  estimate  of  it  has  not  been  formed  from  a  hasty  exami- 
nation, but  after  an  intimate  acquaintance  derived  from  frequent  consultation  of  it  during  the  past  nine  or  ten 
years.  The  editors  are  practitioners  of  established  repiuation,  and  tlie  list  of  contributors  embraces  many  of  the 
most  eminent  professors  and  teachers  of  London,  Edinburgh,  Dublin  and  Glasgow.  It  is,  indeed,  the  great  merit 
of  this  work  that  the  principal  articles  have  been  furnished  by  practitioners  who  have  not  only  devoted  especial 
attention  to  the  diseases  about  which  they  have  written,  but  have  also  enjoyed  opportunities  for  an  extensive 
practical  acquaintance  with  them, — and  wliose  reputation  carries  the  assurance  of  their  competency  justly  to 
appreciate  the  opinions  of  others,  while  it  stamps  their  own  doctrines  with  high  and  just  authority." — American 
Medical  Journal. 

•'  Do  young  physicians  generally  know  what  a  treasure  is  offered  to  them  in  Dr.  Dunglison's  revised  edition? 
Without  wishing  to  be  thotiglit  importunate,  we  cannot  very  well  refrain  from  urging  upon  them  tlie  claims  of 
this  highly  meritorious  undertaking." — Boston  Medical  and  Surgical  Journal. 

•'  It  has  been  to  us,  both  as  learner  and  teacher,  a  work  for  ready  and  frequent  reference,  one  in  which  modern 
English  Medicine  is  exhibited  in  the  most  advantageous  light,  and  with  adaptations  to  various  tastes  and  expecta- 
tions. The  Publishers  can  be  sately  relied  on  as  both  able  and  willing  to  carr>'  this  undertaking  through  with  all 
possible  expedition." — Medical  Examiner. 

"  Such  a  work  as  this  has  long  been  wanting  in  this  country.  British  medicine  ought  to  have  set  itself  forth  in 
this  \\"dy  inuch  sooner.  ^Ve  have  often  wondered  that  the  medical  profession  and  the  enterprising  publishers  of 
Great  Britain  did  not.  long  ere  this,  enter  upon  such  an  undertaking  as  a  Cyclopa;dia  of  Practical  Medicine." — 
London  Medical  Gazette. 

'■The  Cyclopa-'dia  of  Practical  Medicine,  a  work  which  does  honour  to  our  country,  and  to  which  one  is  proud 
to  see  the  names  of  so  many  provincial  physicians  attached." — Dr.  Hastings''  Address  to  Provincial  Medical  and 
Surgical  A^svcintion.. 

•'  Of  the  medical  publications  of  the  past  year,  one  may  be  more  particularly  noticed,  as  partaking,  from  its  ex- 
tent anil  the  number  of  contributors,  somewhat  of  die  nature  of  a  ii.alional  undertaking,  namely,  the  •Cycio]iadia 
ol  i'ractical  .Medicine.'  It  accomplishes  what  has  been  noticed  as  most  <lesirable.  by  presenting, on  several  impor- 
tajit  topics  of  medical  inquiry,  full,  comprehensive,  and  well-digested  expositions,  showingthe  present  state  of  our 
knowledge  on  each.  In  this  country,  a  work  of  this  kind  was'mucli  wanted :  and  that  now  supplied  cannot  but 
be  deeined  an  important  acquisition.  The  diflicultics  of  the  undertaking  were  not  slight,  and  it  required  great 
energies  to  surmount  them.  These  energies,  however,  were  possessed  by  the  able  and  distinguished  editors,  who, 
withdiligence  and  labour  such  as  few  can  know  or  appreciate,  have  succeeded  in  concentraling  in  a  work  of 
moderate  size,  a  body  of  practical  knowledge  of  great  extent  airU  usefulness."— Dr.  Barlow's  Addnss  to  tlie  MeU. 
and  Sur.  Association. 

25 


Cyclopsedia  of  Practical  Medicine  continued. 

"This  Cyclopaedia  is  pronounced  on  all  hands  to  be  one  of  the  most  valuable  medical  publications  of  the  day. 
It  is  meant  to  be  a  library  of  Practical  Medicine.  As  a  work  of  reference  it  is  invaluable.  Among  the  contribu- 
tors to  its  pages  it  numbers  many  of  the  most  experienced  and  learned  physicians  of  the  age,  and  as  a  whole  it 
forms  a  compendium  of  medical  science  and  practice  from  which  practitioners  and  students  may  draw  the  richest 
instruction." — Western  Journ.  of  Med.  and  St(rgery. 

'•In  our  last  number  we  noticed  the  publication  of  this  splendid  work  by  I-ea  and  Blanchard.  We  have  since 
received  three  additional  parts,  an  examination  of  wliich  lias  confirmed  us  in  our  first  impression,  that  as  a  work 
of  reference  lor  the  practitioner — as  a  cyclopa;dia  ofpractical  medicine — it  is  admirably  adapted  tothe  wants  of  the 
American  profession.  In  fact,  it  might  advantageously  find  a  place  in  the  library  of  any  gentleman,  who  has 
leisure  and  taste  for  looking  somewhat  into  the  nature,  causes,  and  cure  of  diseases." — Western  Joxirnalof  Med. 
and  Surgery. 

"The  favourable  opinion  which  we  expressed  on  former  occasions  from  the  specimens  then  before  us,  is  in  no 
degree  lessened  by  a  further  acquaintance  with  its  scope  and  execution.'' — Medical  Examiner. 

■•In  conversation  with  practising  physicians,  we  liave  been  gratified  to  find  that  this  work  comes  fully  up  to 
the  high  expectations  formed  of  it  irom  the  complimentary  notices  of  the  .Tournals.  and  that  as  a  work  of  reference 
it  is  regarded  as  superior  to  any  thing  hitherto  published  on  Practical  Medicine." — Western  Journal  of  Med.  and 
Surgery. 


*^*  In  reply  to  the  numerous  inquiries  made  to  them,  respect- 
ing Tvveedie's  Library  of  Practical  Medicine,  the  Publishers  beg 
leave  to  state  that  its  place  is  supplied,  in  a  great  measure,  by  the 
CyclopEedia  of  Practical  Medicine,  a  work  much  more  extended 
in  its  plan  and  execution.  The  works  are  entirely  distinct  and 
by  different  authors.  The  "Library"  consists  of  essays  on  dis- 
eases, systematically  arranged.  The  "Cyclopsedia"  embraces 
these  subjects  treated  in  a  more  extended  manner,  together  with 
numerous  interesting  essays  on  all  important  points  of  Medical 
Jurisprudence,  Materia  Medica  and  Therapeutics,  Obstetrics, 
History  of  Medicine,  &c.,  &c.  by  the  first  physicians  of  England, 
the  whole  arranged  alphabetically  for  easier  reference. 

JUST  PUBLISHED, 

CHAPMAN  ON  FEVERS,  ^0. 

LECTURES  ON  THE  MORE  IMPORTANT 

ERUPTIVE   FEVERS,   HAEMORRHAGES  AND 

DROPSIES,  AND  ON  GOUT  AND  RHEUMATISM, 

DELIVERED  IN  THE  UNITERSITY  OP  PENNSYLVANIA. 

By  N.  chapman,  M.  D., 

Profes.sor  of  the  Theory  and  Practice  of  Medicine,  &c.  &c. 

In  one  neat  octavo  volume. 
This  volume  contains  Lectures  on  the  following  subjects: 

EXANTHEMATOUS  FRVEKS. 
Variola,  or  Small  Pox;  Inoculated  Small  Pox;  Varicella,  or  Chicken  Pox;  Variolre  VacciniaG,  or  Viiccinia,  or 
Cow-pock;  Varioloid  Disease;  Rubeola,  Morbilli.  or  Measles;  Scarlatina  vel  Fehris  Rubra — Scarict  Fever. 

H^AlOKKH.-iiJKs. 
Hfcmoptysis,  Spilting:of  Blood;  H,Tmor?liagla  Narium  or  Hrcniorrhapie  from  tlio  Nose;  Flti'matemcsis,  or  Vomit- 
ing of  Blood;  lla'maturia.-or  Voiding  of  bloody  Urine;  Hajmorrhagia  Uterina,  or  Uterine  lJa.'niorrhage;  Ha;mor- 
rhois  or  H>jcmorrhoids;  Cutaneous  Hamorrhage;  Purpura  >la;niorrhagica. 

DKOP.SIK."^. 
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chronic:  Anasarca;  with  a  Disquisition  on  the  Management  ot  the  whole. 
GOUT.  KHKU  viAI'l.sM    &c    <.V,c. 


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THORACIC   AND   aIdOMINAL   VISCERA. 

DELIVERED  IN  THE  UN  I  VEIiSI'lY   OE  I'ENNSYLVANJA. 

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the  General  Lunatic  Asylum,  near  Nottingham.  5.  Reports  of  the  Medical  Officers  of  the  Lunatic  Asylum  for 
the  County  of  Lancaster.  6.  Fifty-ninth,  Sixty-fourth  and  Sixty -Eighth  Reports  of  the  Visiting  Justices  of  the 
County  Lunatic  Asylum  at  Hanwell.  XIV.  Zeis  on  the  Plastic  Surgery  of  Celsus:  on  Organic  Adhesions: 
and  on  inverted  Toe-Nail.  XV.  Wattman  on  Means  of  Preventing  the  Rapid  Occurrence  of  Fata)  Symp- 
toms in  the  Accidental  Introduction  of  Air  into  the  Veins.  XVI.  Hennemann  on  a  New  Series  of  Subcuta- 
neous Operations.  XVII.  Hiifeland's  Enchiridion  Medicum.  XVIII.  Summary  of  the  Transactions  of  the 
College  of  Physicians  of  Philadelphia.  March  to  October,  1S44.  XIX.  Chapman  on  the  more  important 
Eruptive  Fe.vers,  Haemorrhages  and  Dropsies,  and  on  Gout  and  Rheumatism. 

SUMMARY  OF  THE  IMPROVEMENTS  AND  DISCOVERIES  IN  THE  MEDICAL  SCIENCES. 
Anatomy  and  Phtsiology. — 1.  Scherer  on  the  Coloration  of  the  Blood.  2.  Jobert  de  Lamballe  on  the  Struc- 
ture of  the  Uterus.  3.  Mulder  on  the  products  of  the  oxidation  of  Protein  in  the  Animal  Organism.  4.  Moreau 
on  the  causes  which  determine  the  Sex  in  Generation.  5.  Magendie  on  the  Influence  of  Heat  and  of  Stoves 
on  Animal  Life.  6.  Bernard  and  Barrtswil  on  Alimentary  Substances.  7.  Schvian  on  the  importance  of 
Bile  in  the  Living  Animal  Organism.  8.  Blagnlere  on  Gunshot  Wound  of  the  Anterior  Cerebral  Lobes. 
9.  Boudet  on  the  Chemical  Composition  of  the  Pulmonary  Parenchyma  and  of  Tubercles. 

Materia  Medica  and  Pharmacy. — 10.  Seidlitz  on  Cotton  as  a  Dressing  to  Blisters.  11.  Devay  on  the  mode 
of  preparing  the  Valerianate  of  Zinc.  12.  Boucliardal  on  Croton  Oil  Plaster.  13.  Blillot  on  the  Lithontriptic 
action  of  the  Gastric  Juice.  14.  Gumprecht  on  Cortex  Frangulae.  15.  Scheidemandel  on  the  mode  of  preparing 
some  Narcotic  Extracts  in  small  quantities.  16.  Burton  on  a  new  method  of  making  Medicated  Tinctures. 
17.  Hoffman  on  Caroub  of  Judea  in  Asthmatic  Affections. 

Medical  Pathology  and  Thbrapeutics  and  Practical  Medicine.— 18.  Lossetlt  on  Small-pox  in  persons 
who  had  been  Vaccinated.  19.  Bertini  and  Bellingiere  on  Nitrate  of  Silver  in  Chronic  Diarrhoea.  20.  Bellin- 
giere  on  Balsam  of  Copaiba  in  Chronic  Broirchitis.  21.  Druiit  on  the  uses  of  Pure  Tannin.  22.  FourcauU  on 
the  causes  of  Albuminuria.  23.  Meyer^s  Researches  on  Albuminuria.  24.  Rees  on  the  Pathology  and  Treat- 
ment of  the  Morbus  Brightii,  and  various  forms  of  Ansemia.  25.  Gregory  on  Deaths  from  Srnall-pox  after 
Vaccination,  in  London.  26.  Devay  on  Valerianate  of  Zinc  in  Nervous  Affections.  27.  Ferini  on  a  singular 
case  of  Encephalitis.  28.  Salvagnoli  on  Analysis  of  the  Blood  of  Persons  Exposed  to  Malaria.  29.  (Esterlen 
on  the  Passage  of  Metallic  Mercury  into  the  Blood  and  Solid  Tissues.  30.  Lamothe  on  Epilepsy  caused  by  a 
Foreign  Body  in  the  Ear,  and  cured  by  its  removal.  31.  Symptoms  of  Acute  Pleurisy,  caused  by  Intestinal 
Worms.  32.  J.  and  J.  H.  Smith  on  Sulphate  of  Iron  combined  with  an  Alkaline  Carbonate,  an  Antidote  for 
Prussic  Acid.  33.  Mac  Doiuiel  on  the  Diagnosis  of  Empyema.  34.  Mondiere  on  a  T^nia  evacuated  through 
an  opening  in  the  Abdominal  Parietes.    35.  Trousseau  on  the  Signs  of  Auscultation  in  Young  Children. 

Surgical  Pathology  and  Thekapeutics  and  Operative  Surgery. — 36.  Syme  on  treatment  of  Obstinate 
Stricture  of  the  Urethra.  37.  Reybard  on  Suture  of  the  Intestine.  38.  Bodinier  on  the  Nature  and  Source  of  the 
Liquid  which  flows  from  the  Ear  producing  ffidema  of  the  Scalp.  39.  Danville  on  Gunshot  Wound,  where  the 
charge  passed  from  the  Navel  to  the  Back  without  faial  consequences.  40.  Sayidham  on  mode  of  Reducing 
Partial  Displacement  of  the  Semi-lunar  Cartilages  of  the  Knee-joint.  41.  Porter  on  Operation  for  the  Radical 
Cure  of  Hydrocele.  42.  Two  cases  oi  Luxation  of  the  Iliac  Bone  upon  the  Sacrum.  43.  Singular  cause  of 
Error  in  Diagnosis  of  Affections  of  the  Knee.  44.  Daniell  on  Warty  Excrescences  near  the  Verge  of  the  Anus. 
45.  Daniell  on  Enormous  Steatoma  removed  from  the  Shoulder.  46.  Jtaffreson  on  Operations  for  Removal  of 
Ovarian»Tumours.  47.  Bird  on  Removal  of  a  Diseased  Ovary.  48.  Wiesel  on  Ununited  Fracture  Successfully 
Treated  by  Acupuncture.  49.  Monin  on  Luxation  of  the  Forearm  forwards  without  fracture  of  the  Olecranon. 
50.  Segalas  on  Influence  of  Traumatic  I<esion3  of  the  Spinal  Cord  on  Diseases  of  the  Urinary  Passages.  51. 
Wildebrand  on  the  Treatment  of  Syphilis  by  Tartar-emetic.  52.  Barbiere's  case  of  Recovery  from  Wound  with 
Hernia  of  the  Lung.  53.  Si/me  on  Popliteal  Aneurism  in  a  Child.  54.  Rognetta  on  Epidemic  Erysipelas.  55. 
Inman  on  Mortality  attending  the  operation  of  Tying  the  Large  Arteries.  56.  Vanzetti  on  Fibrous  Tumour  of 
the  Parotid.  57.  7t</ai  on  New  Operation  for  Varicocele.  58.  /nwan  on  Mortality  attending  the  Operation  lor 
Hernia.  59.  Laugier  on  Immovable  Bandages  of  Starched  Paper  for  the  Treatment  of  Fractures  of  tlie  Limbs. 
60.  Cox  on  Gunshot  Wound  of  the  Chest— evacuation  of  the  ball  per  anum.  61.  Wilde  on  Discharges  Irom  the 
Ears.    62.  Sy7ne  on  Bursal  Swelling  of  the  Wrist  and  Palm  of  the  Hann. 

Ophthalmology. — 63.  Morant  on  Epidemic  Ophthalmia.  64.  ^erirarrf's  Method  of  Curing  Lachrymal  Fistulas 
and  Chronic  Lacbrymations  reputed  incurable.  65.  Dalrymfile  on  Cy si  attached  to  the  Anterior  Surface  of  the  Iris. 
Midwifery.— 06.  Prael  on  Caesarian  operation  performed  with  success  both  for  the  mother  and  child ;  rupture  of 
the  uterus  and  of  the  abdominal  parietes  thirteen  months  subsequently,  during  a  second  pregnancy  ;  delivery  of 
the  foetus  through  this  spontaneous  opening;  complele  recovery  of  the  mother,  67.  FiV/k'tV  c;ise  of  Gravid  Uterus 
passing  into  the  Sac  of  an  old  Inguinal  Hernia.— Cassarinn  Section.  68.  Aubinnis  on  Polypus  of  the  Uterus 
adherent  to  the  Placenta  Successfully  Removed.  69.  Gineste.l  on  the  Juice  of  the  Urtiea  Urens  in  Uterine 
Hemorrhage.  70.  Darftey  on  Prolapsed  Uterus— Pregnancy.  71.  Lfc  on  Dropsy  of  the  Amnion  72.  Lee  on  the 
Causes  and  Treatment  of  Uterine  Hemorrliaie,  in  the  latter  months  of  pregnancy.  73.  Lee  on  Retained  Pla- 
centa. 74.  Lis/ranc  on  Diagnosis  of  Inverted  Uterus  and  Polypus.  75.  ]\Iurphy\i  Statistics  of  Obstetr'c  Practice. 
Medical  .Iurisprudence  and  Toxicology.— 76.  O^ice?- on  Arsenic  in  the  Earth  of  Cemeteries.  77.  Ramsay 
on  Aconitum  Napellus.  78.  Jacofc  on  Poisoning  by  Euphorbia  Latliyris.  79.  R«pt\irc  of  the  Omentum.  HI.  Lig- 
Jranc's  opinion  on  some  Disputed  Points  in  Obstetrical  Medical  Jurisprudence.  81.  Hereditary  Insanity,  how 
far,  in  cases  of  alleged  unsoundness  of  mind,  it  may  be  pleaded.  82.  Sitnpson  on  Relative  AN'oigfit  and 
Size  of  the  Male  and  Female  at  Birth.  S3.  Copper  Tanks  at  St.  Helena.  84.  Trial  for  Murder.  SS.^Case  of 
Suicide.     86.  Recent  English  Law  Cases.     87.  Obituary  of  Dr.  ^6i^croJ?!6(e. 

American  I.ntelligence.- Original  Communications. — Horner  on  the  Preservation  of  the  Human  Body  for 
Anatomical  Purposes.  Proceedings  of  the  Association  of  Medical  Superintendents  of  American  Institutions  for 
the  Insane.     Perkins''s  Cases  of  Congestive  Fever. 

Domestic  Summary. — Fourgeattd  on  Mortality  among  Children  in  St.  Louis.  Le  Contt  on  Extraordinary 
Effects  of  a  Stroke  of  Lightning.  Bowles  on  Removal  of  a  Diseased  Ovarium.  Herrick  on  Rupture  of  the 
Spleen.  Marthcns  on  Fracture  during  Pregnancy.  Buck  and  Watsofi  on  Opium  a  Hazardous  Remedy  in  Stran- 
gulated Hernia.  Yellow  Fever  at  Woodville,  Miss.  Davis  on  Colon  Strangulated  by  the  Meso-colon.  Clark 
x>n  Discharge  of  a  Lumbricus  from  the  Male  Urethra.  M^Dowell^s  cases  of  Extirpation  of  Diseased  Ovaria 
JJew  Works.    Death  of  Dr.  Forry,  31 


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32 


SvIrjS. 


